Tai Timu, Tai Pari, the ebb and flow of the tides: working with the Waimatā from the Mountains to the Sea - Anne Salmond; Gary Brierley; Dan Hikuroa; Billie Lythberg (New Zealand Journal of Marine and Freshwater Research, 2022)
This paper emerges from a Marsden project, Let the River Speak, focused on the Waimatā River in Gisborne, bringing insights from mātauranga and wānanga together with a wide range of disciplines to produce innovative and engaged understandings of ki uta ki tai‐the life of rivers from the mountains to the sea. In Te Ao Māori, waterways are relational knots/nodes/strands in a meshwork of whakapapa that arises from exchanges between earth and sky, land and sea. This approach acknowledges the relations between the atmosphere, surface water and groundwater, vegetation cover, land use, water quality and quantity, the sea, plants, animals, micro‐organisms and people; and rivers as beings in their own right, with their own rights. Let the River Speak is codeveloped with the river by a team including iwi researchers, scholars from earth system science, geomorphology, microbiology and infectious diseases, forest ecology, anthropology, creative practice, and business studies. It is holistic, working across different knowledge systems to understand the full complexity of waterways in relationship with people and other life forms over time. At the same time, it is hopeful, providing a relational framework for actions to restore river and estuarine communities to a state of ora (health, well‐being, flourishing).

The advantages and limitations of biophysical modelling as a tool for informing limit setting in New Zealand's barrier‐enclosed estuaries - Karin R. Bryan; Benjamin T. Stewart; Alex M. Port; Hannah F. E. Jones; Conrad A. Pilditch (New Zealand Journal of Marine and Freshwater Research, 2022)
Estuaries are the receiving environment for catchment‐derived contaminants, the fate of which depends on the interplay between the estuarine geomorphology and hydrodynamics. In large estuaries, biophysical processes are spatially and temporally‐diverse, which makes understanding and managing the impact of human activities challenging. Here we use two common modelling approaches to explore the advantages and limitations of biophysical modelling as a tool for limit setting in a large barrier‐enclosed estuary in New Zealand. The model shows the large spatial variation in water quality associated with low upper harbour flushing. Variations can also be attributed to spatial variation in processes (such as denitrification). Although the non‐linear interactions between processes within these models can limit the value of using specific detail of outputs for decision making, the general patterns and sensitivities can be used to define areas, explore connectivity, and provide some information when monitoring data is lacking. Even in a deterministic modelling environment, it can very difficult to attribute water quality variations output at one location to the loading that caused these variations. While biophysical modelling will likely remain a core tool for informing management, any future development of limit setting methods for estuaries should recognise the inherent constraints we describe here.

A socio‐ecological appraisal of perceived risks associated with mangrove (Mānawa) management in Aotearoa New Zealand - Richard Le Heron; Carolyn J. Lundquist; June Logie; Paula Blackett; Erena Le Heron; Shaun Awatere; Jade Hyslop (New Zealand Journal of Marine and Freshwater Research, 2022)
Why have mangroves and their ecosystems been so hotly contested over the last quarter century in Aotearoa New Zealand's northern waters? Central to ‘mangrove mania’ are multiple, competing and often antagonistic perceptions of the perceived risks posed by mangrove presence, their removal and efforts to restore them. Not surprisingly this has led to a chaotic mangrove knowledge space, with significant gaps in knowledge required to understand risks associated with mangrove management. In a socio‐ecological investigation of risk questions relating to the mangrove debate, we reveal how localised contestations of mangroves have been ‘arbitrated’ – in different directions. This state of affairs has resulted from several critical threads: from many sources, pressures and intentions, but all involving the often ill‐specified lens of public opinion, science practice, environmental management procedures, Māori knowledge, community views, land and inshore development, and consenting processes. We systematically examine the trajectory of these critical threads and their interactions, underlying the mangrove debate and the resulting variability in how risks are portrayed. Our evidence suggests that perceived risk of mangrove expansion, and of mangrove removal impacts, is contested and linked to different desired and imagined futures.

What constitutes a wetland in the New Zealand Coastal Marine Area? – a scientific perspective - Philippe Gerbeaux; Terry M. Hume (New Zealand Journal of Marine and Freshwater Research, 2022)
There is often confusion and sometimes controversy over whether a specific habitat or ecosystem is considered a wetland. In 2021, the New Zealand High Court issued a judgement that the wetland rules in the Resource Management (National Environmental Standards for Freshwater) Regulations 2020 (NES‐F) do apply to wetlands in the Coastal Marine Area (CMA), more particularly which ones apply to ‘natural wetlands’. From a scientific standpoint, the term ‘coastal wetland’ can be applied to all wetland types located in New Zealand coastal hydrosystems, including non‐tidal wetlands influenced, at least in part, by coastal processes. This means coastal wetlands can be found within and outside (although adjacent to) the CMA. In order to map the boundaries of wetlands currently identified within the CMA, their seaward and landward limits can be determined as: ‘areas of marine water, the depth of which, at low tide, does not exceed six metres’, and the ‘CMA definition’, respectively.

Estuaries as coastal reactors: importance of shallow seafloor habitats for primary productivity and nutrient transformation, and impacts of sea level rise - Emily J. Douglas; Richard H. Bulmer; Iain T. MacDonald; Andrew M. Lohrer (New Zealand Journal of Marine and Freshwater Research, 2022)
Estuaries are hotspots of primary productivity and nutrient transformation that contribute to food webs and ecosystem functioning locally and in adjacent ecosystems. The depth‐dependence of nutrient transformation and primary productivity rates in the water column and the seafloor were investigated, and the lateral transport of solutes and materials across the estuary mouth were quantified. Using an estuary dominated by shallow soft‐sediment habitats as a case study, the effects of sea level rise (SLR) on productivity and nutrient transformation processes were projected. The estuary was a net importer of dissolved nutrients from the coast, and a net exporter of suspended sediments and chlorophyll a , supporting the notion that estuaries are important nutrient transformation reactors. A significant depth (and light) effect on productivity indicates that increasing stressors associated with climate change that reduce light at the seafloor (SLR and increased turbidity) will negatively impact estuarine productivity. Intertidal and shallow subtidal benthic habitats were responsible for most of the productivity of the estuary and this is likely to be consistent for other shallow estuaries globally. SLR and anthropogenic intervention that prevents landward migration (i.e. seawalls and armouring), will result in the loss of these habitats and their significant contributions to adjacent coastal ecosystems.

Satellite remote sensing of coastal water quality in New Zealand - Mark P. Gall; Matthew H. Pinkerton; Tilmann Steinmetz; Simon Wood (New Zealand Journal of Marine and Freshwater Research, 2022)
Water quality in estuarine and coastal waters of Aotearoa New Zealand is of concern yet currently under‐monitored, reflecting challenges of sampling at regular intervals across large areas. Satellite products are currently underutilised (globally) by management agencies but could be part of a holistic approach. NIWA‐SCENZ (Seas, Coasts and Estuaries New Zealand) is a website providing access to MODIS‐Aqua products at moderate spatial resolution (500 m) across relatively clear coastal waters (Case 1) to turbid coastal waters (Case 2). It also provides advanced analytical tools on an extracted area of interest for trend assessment (Shiny‐SCENZ). For Case 1 areas product accuracy will be comparable to data from other websites using the same algorithms. For Case 2 and transition (blended) areas, although tuned to New Zealand conditions, accuracy of products requires validation. Data availability is mainly impacted by cloud cover, but also adjacency to land and bottom reflection. On average

Ecosystem function responses to nutrient enrichment mediated by mud content in soft sediment habitats - Samuel Thomas; Conrad A. Pilditch; Simon F. Thrush; Candida Savage (New Zealand Journal of Marine and Freshwater Research, 2022)
Estuaries are threatened with increasing sedimentation and nutrients, however research is limited on the interaction of these stressors on ecosystem functions. A field experiment adding nitrogen (N) fertiliser at high (600 g N m −2 ) and medium (150 g N m −2 ) concentrations and control plots was established in two sandy and two muddy sites (mud content 0–15%) to investigate context dependency of nitrogen enrichment on nutrient cycling and primary production. There was a significant interaction of mud x treatment on ammonium (NH 4 + ) fluxes. High N‐addition plots had 133x greater dark NH 4 + efflux than controls in muddy sediments, compared to 17x greater dark NH 4 + efflux in sandy sediments. Net primary production increased with mud content, while photosynthetic efficiency of the microphytobenthos (GPP chl ‐a ) decreased above 4% mud. Mud content also affected the bivalve, Austrovenus stutchburyi (>30 mm), macrofaunal abundance and functional groups, and their influence on nutrient cycling. Thus minor increases in mud can alter the ecosystem response to nutrient enrichment directly through changes in sediment properties and indirectly by affecting the bivalves and macrofauna that influence these processes. This study highlights how multiple stressors interact to predispose estuaries to tipping points.

Untangling the Gordian knot: estuary survival under sea‐level rise and catchment pollution requires a new policy and governance approach - Stephen C. Urlich; Jazmynn L. Hodder‐Swain (New Zealand Journal of Marine and Freshwater Research, 2022)
Many estuaries are squeezed between sea‐level rise, coastal hardening and adverse cumulative effects from unsustainable catchment activities. In Aotearoa New Zealand, there is little planning to provide future accommodation space for estuaries. A complex knot of policies and plans, and accompanying poor implementation also affect ecological sustainability. We examine these issues for Brooklands Lagoon/Te Riu o Te Aika Kawa, a tidal lagoon northeast of Christchurch/Ōtautahi. It is within the takiwā of Ngāi Tahu iwi and Ngāi Tūāhuriri hapū, and the jurisdictions of Christchurch City Council and Environment Canterbury. The estuary is influenced by three rivers, and surrounding land use is managed under three different statutory resource management plans, along with several non‐regulatory strategies and organisational management plans. However, these plans are poorly integrated and estuarine ecological health is compromised. The incoming tide of resource management and local government reform will add complexity, but also an opportunity to accommodate and enhance the estuary as a blue carbon sink, and to restore cultural and ecological values. This requires specific recognition of estuaries in the proposed managed retreat and spatial planning laws, and within the replacement resource management statute. Legal recognition of Indigenous customary rights could also produce novel governance models to improve management.

Cluster analysis reveals latent structure in stakeholder interests relevant to the management of Blueskin Bay estuary, Otago, Aotearoa New Zealand - Simone D. Langhans; Alice Neilson; Marc Schallenberg (New Zealand Journal of Marine and Freshwater Research, 2022)
Community participation is increasingly embedded into environmental policy with the aim of accelerating transformative change towards sustainable management. A common approach to engaging with communities is through key stakeholders, who are still often selected ad hoc based on their activities. We tested an analytical approach for identifying distinct groups of community preferences as part of a case study to develop a community‐led management plan for Blueskin Bay estuary and its catchment. We interviewed 36 community members to elicit their preferences for predefined management objectives following a standardised protocol. Using an agglomerative hierarchical analysis, we determined value‐preference clusters for high‐level management objectives and more specific objectives. At both levels combined, preference clusters were attributed to some of the commercial interests, such as cockle harvesting, forestry or tourism, which we also identified ad hoc based on their activities in the Blueskin Bay area. However, in addition, cluster analyses revealed five additional preference types: Urban Development Advocates, Cultural Environmentalists, Economic Environmentalists, Integrative Thinkers and those with Diverse Interests. We conclude that cluster analysis more objectively and specifically maps community preferences and, consequently, increases the robustness of collaborative environmental management processes, such as the one underway for Blueskin Bay estuary.

Taura kuku: prioritising Māori knowledge and resources to create biodegradable mussel spat settlement lines for shellfish restoration in Ōhiwa harbour - Kura Paul‐Burke (Ngāti Awa, Ngāti Whakahemo); Rokahurihia Ngarimu‐Cameron (Te Whānau ā Apanui, Te Whakatōhea); Joe Burke (American); Richard Bulmer (Aotearoa European); Kerry Cameron (Ngāti Kahungungu, Ngāti Porou); Tuwhakairiora O'Brien (Ngāti Awa); Charlie Bluett (Ngāti Awa); Megan Ranapia (Ngāti Awa, Tainui) (New Zealand Journal of Marine and Freshwater Research, 2022)
Mātauranga Māori (Māori knowledge) is grounded in place‐based, multi‐generational knowledge and the connection of that knowledge with the environments from which it is derived. It takes for granted that all elements of the natural world are related, and it is upon those relationships that survival depends. A Māori worldview advocates for the responsibility of each generation to pass onto their descendants at least as good a supply of resources as they, themselves, had inherited. For Māori, the wellness of the environment is a direct reflection on the wellness of the people. This article provides an overview of a practical mātauranga Māori‐led marine restoration project in Ōhiwa harbour. The transdisciplinary project worked with a traditional Māori master weaver and kaumātua (tribal elders) to develop biodegradable taura kuku (green‐lipped mussel spat settlement lines, hereafter taura kuku) made from traditional Māori plant biowaste and other natural materials. The taura kuku proved a successful tool for the recruitment and settlement of wild mussel spat assisting shellfish restoration and increasing marine biodiversity in the culturally and ecologically important mahinga kai (traditional food basket) of Ōhiwa harbour.

Transcending boundaries: transitioning toward integrated estuary management in Aotearoa New Zealand - Dana E. Clark; Joanne Clapcott; Eleanor Gee; Andrew Lohrer; Kura Paul‐Burke; Clive Howard‐Williams (New Zealand Journal of Marine and Freshwater Research, 2022)

Participatory processes and the evolution of environmental agendas in estuary restoration: the Maketū case - Patrick Barrett; Priya Kurian; Raven Cretney; Paula Blackett; Erena Le Heron; Richard Le Heron (New Zealand Journal of Marine and Freshwater Research, 2022)
The article analyses participatory processes in estuary restoration in Maketū on the East Coast of the North Island to examine how evolving relational dynamics amongst key stakeholders and Māori led to the achievement of a collective environmental imaginary. The case, marked by a history of conflict over the diversion of the Kaituna River and resulting estuary degradation, led to a focussed period of community engagement between 2006 and 2009 which established a collective intention to restore the ecological health of the estuary. Ongoing community engagement has been a feature of restoration project design and implementation. In examining this case, we draw on the concept of imaginaries, referring to shared visions of desirable futures, to explore how ‘imaginaries of process’ and ‘imaginaries of outcome’ played out among a heterogeneous set of stakeholders and Indigenous actors. We undertake a discourse analysis of relevant documents and of interviews and focus groups with 25 participants to demonstrate how inclusive participatory processes were used as a technique to resolve estuary degradation, address historical grievance between Māori, the community and local authorities, and reset the governance and management relationships between these actors.

Historical data provides context for recent monitoring and demonstrates 100 years of declining estuarine health - Hannah F. E. Jones; Stephen Hunt; Janine Kamke; Michael Townsend (New Zealand Journal of Marine and Freshwater Research, 2022)
Estuaries are complicated systems to manage effectively, requiring the monitoring of robust environmental indicators to assess health and detect changes. Routine estuarine monitoring programmes in New Zealand have only existed for 30 years at most, but estuaries have been significantly affected by anthropogenic pressures for at least 100 years. We reconstructed long term changes in indicators of estuarine health using historical information from sediment cores and aerial photographs, and combined this information with recent monitoring data. This study is focused on four estuaries in the Waikato region of New Zealand, but the findings are likely applicable elsewhere. Sediment accumulation rates increased by orders of magnitude c. 100 years ago, but mangrove forests only started to rapidly expand c. 50 years ago, which coincided with the intensification of agriculture and urban development, and resultant declines in freshwater quality. Over the past 20 years, state of the environment monitoring shows declines in benthic health at most monitoring sites, as well as continuing sediment accumulation and mangrove expansion in some places. This adds to the weight of evidence that environmental management has not been sufficient to safeguard estuarine health and demonstrates the magnitude of change in these systems over the past 100 years.

Sea to the mountains: quantifying freshwater eel and trout diet reliance on marine subsidies from upstream migrating fish - Simon D. Stewart; Robin Holmes; Yvonne Vadeboncoeur; Sarah J. Bury; Sarah Crump (New Zealand Journal of Marine and Freshwater Research, 2022)
Despite the Southern Hemisphere's high proportion of endemic diadromous fish, the trophic role of upstream migrating forage fish in freshwater ecosystems remains unquantified. We combined food web δ 13 C and δ 15 N analyses with fish biomass estimates to quantify estuarine resource contribution (from the ecologically significant Waituna lagoon) to the diet and growth of the apex predators, longfin eels ( Anguilla dieffenbachii ) and brown trout ( Salmo trutta ) in Waituna Creek, Southland, Aotearoa (New Zealand) during 2019 and 2021. Our results demonstrated that exceptionally high biomasses of large predatory fishes (610–830 kg km −1 ) were maintained in a degraded agricultural catchment through connectivity to a near‐pristine estuarine lagoon. Īnanga ( Galaxias maculatus ) migrating upstream from the lagoon supported 60%–80% of longfin eel and 40%–90% of brown trout biomass over the two years sampled. Mass‐balance modelling suggested that large predatory fish in the Waituna Creek consume about two tonnes of migrating whitebait annually. These findings highlight the wider role of estuarine/marine subsidies in structuring New Zealand freshwater food webs and challenge the orthodoxy of ‘restoring streams from the headwaters down’. Estuarine ecosystems may be more important than headwater areas for sustaining large predatory fish, such as longfin eels, when they are food limited.

Understanding the consequences of sea level rise: the ecological implications of losing intertidal habitat - Vera Rullens; Stephanie Mangan; Fabrice Stephenson; Dana E. Clark; Richard H. Bulmer; Anna Berthelsen; Josie Crawshaw; Rebecca V. Gladstone‐Gallagher; Sam Thomas; Joanne I. Ellis; Conrad A. Pilditch (New Zealand Journal of Marine and Freshwater Research, 2022)
Sea level rise (SLR) has been described as one of the greatest potential causes of ecosystem disruption, putting many coastal areas at risk of irreversible changes. However, the loss of intertidal areas from SLR and the associated ecological and social repercussions receive little attention. Within estuaries, extensive intertidal areas harbour a variety of habitats and communities and represent hotspots of ecosystem functions. Any changes to their distribution or extent are likely to have far reaching implications. Here we summarise the ecological consequences of a reduction in intertidal area from increasing SLR, and the implications for people, management and planning. To facilitate this discussion, changes in the occurrence and abundance of two ecologically and culturally important intertidal shellfish species ( Austrovenus stutchburyi and Macomona liliana ) were modelled under different SLR scenarios for Tauranga Harbour, Aotearoa New Zealand. We highlight how the squeezing of intertidal areas will likely alter the distribution and extent of key habitats and communities, and discuss the implications for coastal food webs, ecosystem functioning and service provision. Pre‐emptive planning and adaptive management are needed that incorporate ecological losses in risk assessments and focuses on pro‐active solutions to increase resilience to the effects of SLR.

Arachidonic acid matters - Houguo Xu; Xiaoxue Meng; Yuliang Wei; Qiang Ma; Mengqing Liang; Giovanni M. Turchini (Reviews in Aquaculture, 2022)
Throughout the evolution of fish nutrition science, the importance of dietary arachidonic acid (ARA, 20:4n‐6) has been somewhat overlooked, likely due to the polarizing research focus on docosahexaenoic (DHA, 22:6n‐3) and eicosapentaenoic (EPA, 20:5n‐3) acids. Nevertheless, especially during the past two decades, increasing attention has been paid to the requirements and functions of ARA in fish nutrition, and a number of relevant studies have now been conducted on a series of fish species, including both marine and freshwater species. Those studies revealed important and diverse functions of ARA in various physiological processes, such as growth, reproduction, stress resistance, pigmentation, immunity, lipid deposition and bone development. The results of the present review, in addition to providing a state‐of‐the‐art summary of current knowledge, also revealed the complexity of ARA functions in terms of dosages, species, development stage, sex and feeding period, as well as in terms of interaction between ARA and other nutritional or non‐nutritional factors.

The dawn of closed‐cycle spiny lobster aquaculture - David S. Francis (Reviews in Aquaculture, 2022)

Recent advances and future directions in practical diet formulation and adoption in tropical Palinurid lobster aquaculture - Leo Nankervis; Clive Jones (Reviews in Aquaculture, 2022)
The spiny lobsters Panulirus ornatus and Panulirus homarus are important developing tropical aquaculture species, with high demand and limited supply. The established industry in Vietnam relies on wild‐caught mixed seafood bycatch as feed, a practice linked to water quality degradation and potentially disease proliferation in lobster aquaculture, necessitating formulated feed development. The emerging Indonesian and Australian industries lack the crustacean and mollusc component of the seafood bycatch used in Vietnam, increasing the need for manufactured feeds. The development of such feeds is reliant on knowledge of nutrient requirements, ingredient quality, physical feed requirements, and the link between feeding behaviour and feeding methods. This review will elaborate on the development of these knowledge areas to date and outline the two main reference diet recipes that are available as the basis for future research. Research to date has focused on developing a feed recipe that will be consumed and supports adequate growth rather than steering commercial least‐cost formulation practices. Future research is clearly needed to inform formulation, but equally an understanding of the disparate emerging lobster farming industries and their drivers for the adoption of formulated feeds is required to ensure that such research is applied. This will require engagement throughout the supply chain to ensure that research is implementable and to address farmer perception toward formulated feeds. Technical aspects of feed manufacture and scale‐up of feed developments will be critical to the adoption of research results, while validation through semi‐commercial benchmarks and demonstration farm models are expected to increase commercial uptake of developed feeds.

Spanish abstracts (Reviews in Aquaculture, 2022)

Transcriptomics in advancing portunid aquaculture: A systematic review - Khor Waiho; Mhd Ikhwanuddin; Nor Afiqah‐Aleng; Alexander Chong Shu‐Chien; Youji Wang; Hongyu Ma; Hanafiah Fazhan (Reviews in Aquaculture, 2022)
The rapid advancement of next‐generation sequencing technologies has promoted the use of transcriptomics in non‐model organisms, including species in the aquaculture sector. Compared to that of other crustacean species, portunid crab aquaculture is impeded by the insufficient knowledge of their biological and physiological processes. This systematic review summarised the advances in transcriptomics in cultured portunid crabs using a systematic literature review methodology. The filtered transcriptome dataset comprised 66 articles from four genera: Scylla , Portunus , Callinectes and Charybdis . At the species level, Scylla paramamosain and Portunus trituberculatus were the two most studied species, highlighting their importance in the aquaculture sector. The affordable cost of RNA sequencing (RNA‐Seq) led to an increase in transcriptome‐related research in portunid crabs and made available a huge repertoire of differentially expressed genes (DEGs) and single nucleotide polymorphisms (SNPs). We further discussed the transcriptomic advances based on six main functional categories, that is, ‘growth and moulting’, ‘gonadal development and reproduction’, ‘nutrition metabolism’, ‘disease and immunity’, ‘toxicology and stress’ and ‘general transcriptomic profiling’. In general, transcriptomic studies of portunid crabs, specifically the DEGs and pathways allow an in‐depth understanding of the biological and physiological processes involved at different growth stages or under various conditions based on the difference in gene transcriptional activity. SNPs obtained from the transcriptome data are useful in many genetic improvement‐related downstream applications, including the construction of genetic linkage maps and as population genetic markers. Future directions, such as hybrid approaches of long‐read and common RNA‐Seq, and the incorporation of other omics were also discussed.

Barriers in European spiny lobster ( Palinurus elephas ) aquaculture: What we know so far? - Adam L. K. Yeap; Cecília de Souza Valente; Finnian Hartnett; Ellie‐Ann Conneely; Majbritt Bolton‐Warberg; Simon J. Davies; Mark P. Johnson; Alex H. L. Wan (Reviews in Aquaculture, 2022)
Palinurids, also known as spiny lobsters, are high‐value seafood, which is economically important for many European and Asian seafood trades. However, the reduction of wild European spiny lobster populations produces a need for developing alternative renewable strategies to meet current and future demands. Aquaculture of spiny lobsters has the potential to become of major economic importance in the coming years with growing markets in Asia, Europe, and America, with Palinurus elephas being a promising candidate species for use in the commercial culture and stock enhancement of natural fisheries. This is due to its shorter larval periods and rapid growth to the critical puerulus stage compared with other spiny lobster species. While we have a basic understanding of the lifecycle and biology of P. elephas , much of this is based on work undertaken on similar species globally. There are many gaps in our knowledge that need to be addressed to make its aquaculture viable with appropriate feeds being an immediate issue as well as many other husbandry‐related factors. Previous studies act as a platform providing a baseline for further research and highlighting constraints. Developments in the use of P. elephas are promising due to realistically bridgeable knowledge gaps, the likelihood of producing sustainable food and the high commercial value of spiny lobsters. This review identifies our present state of knowledge and outlines the scope for further research and necessary technological developments to make it a viable contribution towards crustacean aquaculture in Europe.

Portuguese‐Brazilian abstracts (Reviews in Aquaculture, 2022)

Rapeseed proteins as fishmeal alternatives: A review - Frederik Kaiser; Harvey Harbach; Carsten Schulz (Reviews in Aquaculture, 2022)
The aquaculture sector has been the key factor in meeting the growing demand for high‐quality food by contributing significantly to the global fish production. The portion of fishmeal in aqua feeds has been decreased significantly in recent years, however, increased production in aquaculture still led to demands of fishmeal that cannot be covered by sustainably caught small pelagic fish. Hence, alternatives for fishmeal in aqua feeds are an inevitable necessity. Different plant proteins have been evaluated in the past and rapeseed proteins are considered valuable protein sources for fishmeal‐free aqua feeds. Rapeseed is highly available on a global scale and provides one of the most balanced amino acid composition among plant‐based protein sources. Additionally, rapeseed cultivation is characterised by low production costs, ecological and economic benefits in cereal‐dominated agriculture and provision of two highly nutritive products. Subsequently, rapeseed proteins have been intensely investigated over the past decades and knowledge of the application of these proteins in diets for different species of fish has improved dramatically. However, there is no adequate complete review for the application of rapeseed proteins in aqua feeds. This review outlines and discusses the relevant factors influencing the inclusion of rapeseed proteins as fishmeal alternatives in fish diets and highlights provisional thresholds for anti‐nutritive substances as well as future research needs.

White spot syndrome virus host range and impact on transmission - Desrina; Slamet B. Prayitno; Marc C. J. Verdegem; Johan A. J. Verreth; Just M. Vlak (Reviews in Aquaculture, 2022)
White spot syndrome virus (WSSV), the etiological agent of white spot disease (WSD), is a significant pathogen affecting shrimp farming industry worldwide. White spot syndrome virus is a generalist virus mainly infecting decapod crustaceans. The aims of this review were to: (1) Re‐evaluate and update the status of reported WSSV host and vector species based on the methods used when detecting replication and transmission to shrimp and 2) make a critical evaluation of existing literature on the presence of WSSV in aquatic organisms and the potential role these organisms might play in the transmission of WSSV in pond systems and the wild. An evaluation of literature about WSSV reported host and vector species showed an increase from 33 families to 50 families including 11 families of non‐crustacean hosts, proved the virus continues to spread beyond farmed shrimp and the shrimp pond environment. White spot syndrome virus transmission in the aquatic environment is complex as depicted in our model. Containment of WSSV in ponds and the natural environment is challenging, mainly because of its generalist nature and a lack of understanding about (1) WSSV transmission in the aquatic setting, (2) the route of WSSV transmission among species exist in the aquatic environment and (3) information on the transmission dynamics between WSSV in farmed crustaceans and non‐farmed animals. Information presented in this review provides the research direction on methods to control WSSV.

Decapod iridescent virus 1: An emerging viral pathogen in aquaculture - Xuzheng Liao; Jianguo He; Chaozheng Li (Reviews in Aquaculture, 2022)
Decapod iridescent virus 1 (DIV1) is an emerging viral pathogen that seriously threatens crustacean farming and has caused enormous economic losses in recent years. This virus was originally isolated and identified from diseased crayfish Cherax quadricarinatus and shrimp Litopenaeus vannamei in Fujian and Zhejiang, China, in 2014 by two research groups. In 2019, the Executive Committee of the International Committee on Taxonomy of Viruses approved DIV1 as a member of the new genus Decapodiridovirus in the family Iridoviridae. DIV1 is icosahedral in shape and contains a single linear double‐stranded DNA genome of approximately 165 kb. DIV1 can infect many host species, including freshwater and seawater crustaceans, but infected hosts do not show unique pre‐clinical signs, which increases the difficulties in the diagnosis and treatment of this disease. Increasing progress has been made towards understanding many aspects of this virus, including its classification, genomic features, transmission mode, host range, pathogenicity, clinical symptoms, histopathology, detection method and host immunity in response to infection. In this review, we provide an overview of recent progress towards understanding the epidemiology and pathobiology of disease caused by DIV1 and highlight the future research prospects in control and prevention strategies.

Arabic abstracts (Reviews in Aquaculture, 2022)

Structural insights into proteins from white spot syndrome virus: Perspectives on structure‐based anti‐viral strategies - Aritreyee Datta; Shaikh Nausad Hossain; Chinmayee Mohapatra; Dileep Vasudevan (Reviews in Aquaculture, 2022)
White spot syndrome virus (WSSV) causes severe disease in crustaceans, specifically shrimp, leading to substantial economic losses to the aquaculture industry. Existing treatment methods fail to sufficiently curb the occurrence and spread of the disease, necessitating the development of effective control and treatment strategies. Structural studies have primarily focused on envelope proteins and a few non‐structural proteins involved in host entry, viral replication, viral assembly and host immune evasion, thus presenting themselves as potential drug targets. Here, we provide a comprehensive review of the insights gained from such structural elucidations to contribute to developing novel therapeutic strategies. In addition, we touch upon the current and future perspectives towards structure‐based drug or vaccine development against WSSV.

Chinese abstracts (Reviews in Aquaculture, 2022)

Usage pattern of chemicals, biologicals and veterinary medicinal products in Indian aquaculture - Prasanna K. Patil; Sudhansu S. Mishra; Pravata K. Pradhan; Sanjib K. Manna; Jawahar T. Abraham; Haresh G. Solanki; Neetu Shahi; Priyabrata Swain; Satya N. Sahoo; Satheesha Avunje; Krupesha S. R. Sharma; Rajamanickam Geetha; et al. (Reviews in Aquaculture, 2022)
The use of chemicals, biologicals and veterinary medicinal products (VMPs) helps in healthy and sustainable fish production. Information on the use of these products is essential for assessing farming practices, potential human health and environmental risks. A questionnaire‐based nationwide survey covering aquaculture farms ( n = 2936) producing carps, tilapia, pangasius and rainbow trout in freshwater and shrimp in brackishwater estimated the use of 52 different types of inputs which included disinfectants (597 g t −1 ), probiotics (2.28 kg t −1 ), environmental modifiers (22.82 kg t −1 ), nutritional supplements (1.96 kg t −1 ), natural anti‐infective agents (293 g t −1 ), herbicide and piscicides (844 g t −1 ), antibiotics (2 mg PCU −1 ), antifungal (4 mg PCU −1 ), and antiparasitic (14 mg PCU −1 ) agents. The bulk of these inputs was used for soil and water quality improvement and had low environmental and human safety concerns. The multivariate analysis revealed significant variation in the frequency and quantity of compounds use among farm groups. Redundancy analysis revealed a significant association between the number of products used and stocking density. The survey also showed a considerable influence of education and farming experience on the usage pattern of aquaculture inputs. Results of the study indicated greater reliance of farmers on the use of disinfectants for biosecurity, nutritional supplements for enhanced growth and environmental modifiers for maintaining soil and water quality in culture systems. Though there was no use of restricted antibiotics and antiparasitic agents, the development and implementation of standard regulatory guidelines are essential for safe and effective use of inputs for sustainable aquaculture.

The ornamental fighting fish is the next model organism for genetic studies - Gen Hua Yue; Le Wang; Fei Sun; Zituo Yang; Yubang Shen; Zining Meng; Yuzer Alfiko (Reviews in Aquaculture, 2022)
The fighting fish Betta splendens is a freshwater species from Thailand and other Southeast Asian countries. This fish has been domesticated for 1000 years and bred for fighting, various colours, body size and fin types for 600 years. It is one of the most important fish species cultured for the world ornamental fish market. This fish is easy to culture, highly fecund and displays great morphological diversity. Its biology has been studied for over 100 years. Recently, its compact genome and transcriptomes have been sequenced. Genome editing with CRISPR/cas9 has been applied to knock out genes in this fish. Its diverse phenotypes, including colours, colour patterns, fin types, and aggressive behaviour, are complementary to those of other model animals. Therefore, this fish could be the next important model organism for studying phenotypic variation and aggressive behaviour. In this paper, we synthesized knowledge about its aquaculture, biology, genetics, genomic tools, phenotypes and novel insights on phenotypic variation, sex determination and aggression. We hope that the information described in this paper will facilitate genetic studies on phenotypic variations in aquaculture and aggressive behaviour in other species, including humans.

Diversification of farmed fish species: A means to increase aquaculture production in Nigeria - Angela Oboh (Reviews in Aquaculture, 2022)
Aquaculture produces about half the fish consumed globally and is the fastest‐growing food sector. In Africa, fish is one of the major sources of animal protein, and although the need for increased production of farmed fish to make up for the decline in capture fisheries is acknowledged, efforts put into aquaculture in the continent have not yielded commensurate results. The success recorded in aquaculture in Nigeria is based on the production of the African catfish. However, a high level of production and resilience within the aquaculture sector has been shown to be positively correlated with the culture of several species or species items. Thus, enhanced diversification of species and farming systems may boost aquaculture in Nigeria, as diversification of farming systems would allow optimum utilization of the abundant natural resources in the country. Many indigenous fish species that can be domesticated for culture have been identified. A great deal of scientific research and collaboration between major stakeholders, including the government, private industries, research institutions, and researchers, is required, so the production of these species can thrive like the already farmed catfish in Nigeria. As the successful domestication of any fish species takes a lot of time, effort, and resources, the species that have already proven to some extent to thrive in Nigeria, should be explored first. It is recommended that the best strategy for diversification of aquaculture for Nigeria is to increase the use of some already farmed species and the employment of a variety of production systems.

Genome‐wide identification of catfish antimicrobial peptides: A new perspective to enhance fish disease resistance - Jinhai Wang; Baofeng Su; Rex A. Dunham (Reviews in Aquaculture, 2022)
Antimicrobial peptides (AMPs), also known as host defence peptides, are evolutionarily ancient defensive weapons that can combat infections caused by pathogens. Fish‐derived AMPs have shown microbicidal properties, host immunomodulatory responses, and are induced by a variety of factors, especially pathogenic infection and abiotic stress, which may activate downstream signalling pathways to initiate the expression of antimicrobial peptide genes. Large‐scale genome sequencing has been applied in many aquatic animals, providing databases for the systematic identification of putative AMPs in these species. Recently, the whole genome and the proteome of channel catfish ( Ictalurus punctatus ) were released; by taking advantage of the antimicrobial peptide database and combining the proteome of catfish, we established a bioinformatic analysis pipeline to identify catfish AMP repertoire. This review introduces an effective method for the identification and development of putative AMPs based on protein datasets, and summarizes the structural properties, immunomodulation and molecular responses in vivo of catfish AMPs. In addition, the evaluation of the antibacterial activity of synthetic or isolated AMPs in vitro , and the applications of AMPs in fish via genetic engineering and clustered regularly interspaced short palindromic repeats associated proteins system (CRISPR/Cas9) were presented, which supports antimicrobial research and aquaculture therapy. The summary and comparison of these AMPs will enhance our understanding and their cross‐species applications. Combined with current genetic engineering and genome editing techniques, it is possible to promote the development of immune processes to protect valuable aquatic animals from infectious diseases.

Balancing protein and energy in Nile tilapia feeds: A meta‐analysis - Gauthier D. P. Konnert; Walter J. J. Gerrits; Sander W. S. Gussekloo; Johan W. Schrama (Reviews in Aquaculture, 2022)
Farmed fish are increasingly grown in intensive and semi‐intensive systems where most nutrients are provided by formulated feeds. These are formulated to minimise costs and optimise growth, notably the rate of muscle protein synthesis ( i.e ., fillet). Protein synthesis depends on the availability of amino acids ( i.e ., protein) and energy. Thus, fish feeds are often formulated to provide a balanced ratio of protein to energy (P:E). Above and below the optimal dietary P:E, absorbed protein and energy are expected to be under‐utilised for body protein synthesis, respectively. Estimates of the optimal dietary P:E vary largely for Nile tilapia ( Oreochromis niloticus (L., 1758)). Published values range from 13 to 26 g of dietary protein per MJ of energy. Here, we challenge the idea that growth, protein utilisation efficiency and body composition can all be simultaneously optimised, when Nile tilapia are fed an optimal dietary P:E. Through linear and non‐linear regression meta‐analyses, we quantitatively describe the effects of protein and energy intake on nutrient partitioning, feed efficiency and growth. We find linear relationships between the dietary P:E and protein retention efficiency. The lack of an inflection contradicts the existence of an optimal P:E. Our regressions of protein and energy intake versus protein gain, indicate that protein gain is often simultaneously limited by both protein and energy intake, and may be limited by other factors than protein and energy intake, such as a maximal protein deposition capacity (PD max ). We conclude that there is no physiological basis for an optimal P:E in Nile tilapia feeds.

Molecular farming: Expanding the field of edible vaccines for sustainable fish aquaculture - Alžbeta Mičúchová; Veronika Piačková; Ivo Frébort; Tomáš Korytář (Reviews in Aquaculture, 2022)
Vaccines represent one of the most promising strategies for mitigating economic losses imposed by infectious diseases to global aquaculture. While the majority of commercial vaccines employ injection as the main route of delivery, a substantial body of research explores other avenues for the stimulation of protective immunity. Oral vaccines, representing the most favourable and convenient solution for the aquaculture industry, have been at the forefront of scientific interest for the last couple of decades. The orchestrated effort resulted in identifying the main roadblocks on the path to an ideal edible vaccine and provided several ingenious solutions improving the activation of immunity, ensuring the stability of administered antigens and their uptake upon the passage through the stomach. In the presented review, we describe advances in the available knowledge of the processes prerequisite for developing protective mucosal vaccines and focus readers' attention on the untapped potential of plant‐based production systems in this effort. We propose that these approaches not only meet production demands but also fulfil all requirements of an oral vaccine, addressing all the obstacles, previously solved via separate strategies, in one platform. Thus, combined with the available knowledge of molecular adjuvants and produced for a fraction of the cost, plant‐based production, so‐called molecular farming, is an ideal candidate for vaccine development, paving the road to sustainable aquaculture.

Issue Information (Reviews in Aquaculture, 2022)

Moving towards improved surveillance and earlier diagnosis of aquatic pathogens: From traditional methods to emerging technologies - Scott MacAulay; Amy R. Ellison; Peter Kille; Joanne Cable (Reviews in Aquaculture, 2022)
Early and accurate diagnosis is key to mitigating the impact of infectious diseases, along with efficient surveillance. This however is particularly challenging in aquatic environments due to hidden biodiversity and physical constraints. Traditional diagnostics, such as visual diagnosis and histopathology, are still widely used, but increasingly technological advances such as portable next generation sequencing (NGS) and artificial intelligence (AI) are being tested for early diagnosis. The most straightforward methodologies, based on visual diagnosis, rely on specialist knowledge and experience but provide a foundation for surveillance. Future computational remote sensing methods, such as AI image diagnosis and drone surveillance, will ultimately reduce labour costs whilst not compromising on sensitivity, but they require capital and infrastructural investment. Molecular techniques have advanced rapidly in the last 30 years, from standard PCR through loop‐mediated isothermal amplification (LAMP) to NGS approaches, providing a range of technologies that support the currently popular eDNA diagnosis. There is now vast potential for transformative change driven by developments in human diagnostics. Here we compare current surveillance and diagnostic technologies with those that could be used or developed for use in the aquatic environment, against three gold standard ideals of high sensitivity, specificity, rapid diagnosis, and cost‐effectiveness.

Farm‐scale models in fish aquaculture – An overview of methods and applications - Killian Chary; Daniele Brigolin; Myriam D. Callier (Reviews in Aquaculture, 2022)
Models are important tools to address sustainability challenges associated with developing aquaculture at farm, regional and global scales. Farm‐scale models (FSMs), which are integrated mathematical models developed to simulate farm operations, can quantify energy, mass or economic input flows and predict a variety of outputs such as fish biomass, waste and by‐products. The variety of farming systems, equations available to build the models, and objectives of applications and intended users has resulted in the publication of wide range of FSMs. We performed a narrative review of 36 fish FSMs published from 1985–2021 to address several questions: Can the main characteristics of these models be defined? How do the farming system studied and the objectives of the study influence model development? What are the main modelling techniques available to simulate the main processes of a fish farm, and what are their advantages and disadvantages? How can FSMs help address sustainability challenges of aquaculture? This review discusses advances, limitations and future lines of research related to FSMs to help select existing models, or develop new ones, that are suitable for their intended use and users. The article is structured according to the main steps of the modelling process: (i) definition of scope and objectives; (ii) process formulation and model selection at individual, cohort and farm levels; (iii) implementation and evaluation; and (iv) applications (e.g. precision fish farming, IMTA modelling, supporting spatial management, life cycle assessment). At each step, recommendations are provided and research needs are stated.

Prokaryotic diversity in marine and freshwater recirculating aquaculture systems - Stefanos Moschos; Konstantinos Ar. Kormas; Hera Karayanni (Reviews in Aquaculture, 2022)
Intensive aquaculture food production has been continually increasing over the past decades. Recirculating aquaculture is an innovative technology which relies on water reuse and removal of toxic metabolites by utilizing specific prokaryotic groups such as nitrifiers, settled in special biofilters. Focused on recent next generation sequencing‐based studies on the microbiome of recirculating aquaculture systems, this review highlights dominant genera and families, and investigates their possible metabolic function in key niches within recirculating aquaculture systems (rearing water, biofilters and fish mucosal microbiome), while aiming to identify core prokaryotic groups across studies. A total of 136 genera belonging to 77 families and 13 phyla have been characterized as dominant or functionally important in relevant studies, mainly isolated from nitrification biofilters, system water and intestinal samples of the farmed species. Proteobacteria is undoubtedly the most abundant phylum, followed by Bacteroidetes, Firmicutes and Actinobacteria, while Rhodobacteriaceae and Flavobacteriaceae are the common dominant families. Nitrosomonadaceae and Nitrospira members are enriched in biofilter samples and serve as the most common ammonium and nitrite oxidizers, respectively. Composition of dominant genera appears system specific due to unique characteristics of individual RAS designs, although faint community patterns emerge when examining RAS by their salinity level. Considering the number of ribosomal RNA operon copies, 75% of genera are likely slow growers, dominating biofilter and water communities, whereas the few fast‐growing opportunists are mainly associated with the intestine of farmed species. Finally, this review stresses the lack of information regarding archaeal and microeukaryotic communities in recirculating aquaculture systems and prokaryotic–protist interactions.

Current progress in the authentication of fishery and aquatic products using multi‐element and stable isotope analyses combined with chemometrics - Cui Han; Li Li; Xuan Dong; Qinfeng Gao; Shuanglin Dong (Reviews in Aquaculture, 2022)
Fraud occurs frequently in the fishery and aquatic product markets. Therefore, the authentication of fishery and aquatic products has become a crucial issue. Recently, elemental and stable isotope analyses have become popular for aquatic food authentication. In this review, relevant literature was collected to highlight the current progress in the authentication of fishery and aquatic products using multi‐element and stable isotope analyses combined with chemometrics. Both technologies provide valuable insight regarding geographic origin, culture method, and species identification of fishery and aquatic products. Their classification rate varied from 60% to 100% in most studies. The formation of both elemental and stable isotope profiles of fishery and aquatic products is complex and affected by many factors, including diet, biological differences, and culture environment. The classification rate of these methods may be increased by combining multiple technologies, selecting the correct elements and stable isotopes for specific purposes, selecting and verifying proper discrimination methods, and increasing sample sizes. This review provides valuable information to build reliable and stable tracing methods for fishery and aquatic products.

Fruit processing by‐products in the aquafeed industry: A feasible strategy for aquaculture sustainability - Mahmoud A. O. Dawood; Ola A. E. Habotta; Mabrouk Elsabagh; Mohamad Nor Azra; Hien Van Doan; Zulhisyam Abdul Kari; Hani Sewilam (Reviews in Aquaculture, 2022)
The aquaculture sector is steadily growing due to the increasing demand for healthy and cheap animal protein sources. Consequently, the high demand for nutritionally balanced aquafeed increases, but requires sustainable and feasible feed ingredients. However, the high cost of fish and soybean meals opens the door to looking for suitable non‐traditional feed ingredients. The processing of fruits results in high amounts of waste and by‐products, which are risky for the environment but rich in nutritional value. Recycling fruit waste in aquafeed is successfully applied and results in high growth performance, productivity and well‐being of aquatic animals. Fruit by‐products are also potential functional feed additives devoted to their high content of polyphenols, flavonoids, vitamins, minerals, polysaccharides and peptides. As functional components, fruit by‐products enhance the antioxidative and immune responses of aquatic animals and increase their tolerance for biotic and abiotic stressors. In light of reducing antimicrobial chemicals in aquaculture to mitigate antimicrobial resistance, dietary feed additives extracted from fruit by‐products can be used as eco‐friendly substances. The investigations involved in evaluating the incorporation of fruit by‐products and their derivatives in aquafeeds are explored in this review. An overview of the possibility of using non‐traditional plant products in aquaculture as a feasible and sustainable concept is addressed in this review. Academic knowledge with enough information for more development and research to maximise the utilisation of fruit by‐products in the aquafeed industry is also enriched.

Future feed resources in sustainable salmonid production: A review - Sissel Albrektsen; Raine Kortet; Peter Vilhelm Skov; Elisabeth Ytteborg; Susanne Gitlesen; Dorinde Kleinegris; Liv‐Torunn Mydland; Jon Øvrum Hansen; Erik‐Jan Lock; Turid Mørkøre; Philip James; Xinxin Wang; et al. (Reviews in Aquaculture, 2022)
Aquaculture is one of the most resource‐efficient and sustainable ways to produce animal protein. The Food and Agriculture Organization predicts that cultivated aquatic species will provide around 53% of the world's seafood supply by 2030. Further growth of intensive farmed aquatic species may be limited by a shortage of feed resources. The aquaculture sector therefore needs to intensify its search for alternative ingredients based on renewable natural resources. A significant increase in production will require an accelerated transition in technology and production systems, better use of natural available resources, development of high‐quality alternative feed resources and exploitation of available space. The present review discusses the urgent need to identify appropriate alternative ingredients for a sustainable future salmonid production. We describe and evaluate the most promising marine ingredients, including low‐trophic species (mesopelagic fish, zooplankton, polychaetes, macroalgae and crustaceans), novel microbial ingredients (bacteria, yeast and microalgae), insects (black soldier fly, yellow meal worm and crickets), animal by‐products (poultry meal, meat and bone meal, blood meal and hydrolysed feather meal) and by‐products from other commercial productions (trimmings and blood). Furthermore, we discuss the available volumes and need for new processing technologies and refining methods to ensure commercial production of nutritionally healthy ingredients. The essential production steps and considerations for future development of sustainable and safe seafood production are also discussed.

Long‐term variability in deposited fine sediment and macroinvertebrate communities across different land‐use intensities in a regional set of New Zealand rivers - Noah G. Davis; Roger Hodson; Christoph D. Matthaei (New Zealand Journal of Marine and Freshwater Research, 2022)
Macroinvertebrate communities in running waters are commonly used as bioindicators of fine sediment pollution, but few studies evaluate impacts across multiple years. We used a 5‐year dataset from 46 rivers in Southland, New Zealand to investigate the consistency of the relationship between deposited fine sediment and stream macroinvertebrates across three categories of agricultural land‐use intensity (low, medium, and high). We also compared the performance of four widely used invertebrate stream health metrics and their recently developed sediment‐specific counterparts. Linear and non‐linear regressions were fitted and effect sizes were interpreted to identify biologically meaningful relationships ( r 2 ≥ 0.1). Sites within medium‐intensity catchments showed the greatest number of such relationships (29 of 40 cases), compared to low‐ (8) or high‐intensity catchments (23). Invertebrate metrics responded more frequently, and mostly negatively, to increasing sediment in medium‐ and high‐intensity catchments. Overall, sediment‐specific metrics performed better than their widely used counterparts. Our findings show that land‐use intensity influences the multi‐year dynamics of deposited fine sediment and the corresponding stream invertebrate responses. These temporal dynamics can be substantial and should be considered in future stream biomonitoring efforts.

Stable carbon isotope fractionation of fatty acid in sea cucumber ( Apostichopus japonicus ): insights from an experimental study - Xufeng Zhang; Yu Liu (New Zealand Journal of Marine and Freshwater Research, 2022)
Isotope fractionation of fatty acids can reflect the metabolic pathway of fatty acids in organisms, but few studies have been conducted. In this study, stable carbon isotope fractionation of fatty acids in sea cucumber ( Apostichopus japonicus ) was conducted by feeding experiments of comparing the fatty acid profile and δ 13 C of fatty acids in body wall to diet. The results showed that the fractionation of δ 13 C of fatty acids in A. japonicus was −1.588–7.403‰. The fractionation of δ 13 C of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs) was 1.098–7.403‰, −1.588–2.778‰, and −1.559–5.614‰, respectively. The degree of fractionation of δ 13 C of SFAs was greater than that of unsaturated fatty acids (UFAs). We simulated the possible metabolic process of fatty acids in A. japonicus based on fatty acid profile and δ 13 C of fatty acids, indicating that the combination of these two methods could be potentially used in the study of fatty acid metabolism in marine benthic animal of A. japonicus . Our finding provides a new technique for the metabolic pathways of biomolecules in organisms.

Biodiversity of marine helminth parasites in New Zealand: what don't we know? - Jerusha Bennett; Bronwen Presswell; Robert Poulin (New Zealand Journal of Marine and Freshwater Research, 2022)
A full account of the world's species is important for understanding how natural systems are structured, how they function and how they will respond to natural and anthropogenic pressures in the future. Despite the well‐known importance of parasites in natural systems, they are too often underrepresented from studies on biodiversity and ecological functioning. In this review, we provide a quantitative synthesis of the current state of knowledge of helminth biodiversity within New Zealand's marine environment. We report that records of parasitic helminths within New Zealand marine animals are few and uneven across host taxa. A large proportion of parasite species are taxonomically unresolved, with some differences across parasite taxa. Few parasites have their whole life cycles resolved, and the majority are only reported from one host species at one life stage. Most endemic host species are yet to be investigated for helminths and there is likely an abundance of endemic parasite diversity yet to be discovered. Host species of greater conservation concern are being investigated for helminths less frequently than species of low conservation concern. We conclude that little is known about parasitic helminths in New Zealand's marine environment and make recommendations on how to improve this situation.

Habitat use of the amphidromous catfish Genidens barbus : first insights at its southern distribution limit - Esteban Avigliano; Jorge Pisonero; Ana Méndez; Andrea Tombari; Alejandra V. Volpedo (New Zealand Journal of Marine and Freshwater Research, 2022)
White sea catfish Genidens barbus is an endangered amphidromous species distributed between northeastern Brazil and northern Argentine Patagonia, whose migratory behaviour at the southern end of its range is unknown. Here, the migratory patterns of this species were studied including marine and freshwater (Patagonian stock) environments via otolith core‐to‐edge Sr/Ca and Ba/Ca profiles. Based on the Sr/Ca ratio, all specimens were classified as amphidromous with annual cycles of movement between waters of relatively low to high salinity occurring during spring. The core Sr/Ca ratio matched with the reference values for freshwater in all specimens. No evidence of resident freshwater or marine individuals was found. No evident antagonistic relationship was found between both Sr/Ca and Ba/Ca ratios. A Ba/Ca peak was observed followed by a drop coinciding with the core edge, highlighting the need to evaluate the potential transfer from the yolk, and to understand what factors are linked to the growth marks within the first year of life.

The sediment fluorescence–trophic level relationship: using water‐extractable organic matter to assess past lake water quality in New Zealand - Andrew R. Pearson; Bethany R. S. Fox; Marcus J. Vandergoes; Adam Hartland (New Zealand Journal of Marine and Freshwater Research, 2022)
Lake sediments are the physical remnants of past allochthonous and autochthonous carbon and mineral inputs and therefore have the potential to illuminate both past terrestrial carbon cycling and within‐lake biological productivity. However, there are currently no robust, rapid, and inexpensive methods to chemically characterise the organic matter (OM) components in lake sediments, which limits their utility for reconstructing past soil carbon export trends or trophic status. This study explores the use of 3D excitation–emission matrix (EEM) fluorescence spectroscopy of water extractable dissolved organic matter (WEDOM) from lake sediments as a method for reconstructing past soil dissolved organic matter (DOM) export and past lake water quality. Using contemporary lake sediments from 11 New Zealand lakes, we demonstrate that both overall WEDOM fluorescence and protein‐like fluorescence intensity are strong functions of trophic status across lakes. We also demonstrate that protein‐like fluorescence is a function of sedimentary total nitrogen concentrations in palaeo‐sediments from a pristine, high‐altitude lake (Adelaide Tarn). This approach has applications in the evaluation of the trophic status of infrequently monitored lakes and in palaeolimnology.

Population responses of the pulmonate gastropod, Amphibola crenata , reflect estuarine trace metal contamination - Nuwan A. L. De Silva; Islay D. Marsden; Rhian Taylor; Sally Gaw; Chris N. Glover (New Zealand Journal of Marine and Freshwater Research, 2022)
This study assessed the potential of the mud snail Amphibola crenata as a bioindicator of estuarine health. Multiple sites with varying contaminant inputs were identified within a small, shallow estuary (Avon‐Heathcote/Ihutai in the South Island of New Zealand). Population structures of field‐collected A. crenata were related to measurements of sediment trace metal profiles. Whole‐body soft tissue metal concentrations were significantly positively correlated with sediment trace metals for all elements analysed (arsenic, cadmium, copper, nickel, lead and zinc). In terms of population biomarkers, medium‐sized mud snails (7.9–17.9 mm shell length) dominated the population size structure at the most contaminated sites. That sites which were more highly enriched in trace metals were distinguishable by application of a simple population structure assessment, suggests that A. crenata has potential value for evaluating estuarine health. However, further investigation of other biotic and abiotic factors that may influence population structure are required.

Comparing the performance of supervised classification methods on a multispecies fishery of post‐larval galaxiids - Bridget A. Armstrong; Elena Moltchanova; Michael J. H. Hickford; David R. Schiel (New Zealand Journal of Marine and Freshwater Research, 2022)
Galaxiid post‐larvae constitute five of the six species in New Zealand's iconic whitebait fishery. Distinguishing the five species needs to occur at a younger age than is convenient for easy identification. Traditional identification uses subjective characteristics such as colouration of fresh specimens and fin position, but supervised classification methods could be more accurate and less labour‐intensive. We compared the accuracy of six methods (multinomial logistic regression, linear discriminant analysis, quadratic discriminant analysis, naive Bayes, decision tree, and random forest) using total length, wet weight, body depth, and date, latitude and longitude of capture as predictive variables. Four of the galaxiid species were represented in 17,546 observations, but the other species was too rare to analyse. The best method, determined using 10‐fold cross‐validation classification accuracy (95.2% overall), was random forest across all species. The most difficult species to classify correctly (giant kōkopu) was the rarest species included in data with 66.1% accuracy at best. In addition to examining overall accuracy, we show how use of a cost function can improve classification performance with respect to rare species. This research could improve the efficiency of monitoring the composition of the whitebait fishery, and thus management of this occasionally overfished group of fish.

Phylogeographic structure and historical demography of tarakihi ( Nemadactylus macropterus ) and king tarakihi ( Nemadactylus n.sp.) in New Zealand - Yvan Papa; Alexander G. Halliwell; Mark A. Morrison; Maren Wellenreuther; Peter A. Ritchie (New Zealand Journal of Marine and Freshwater Research, 2022)
Tarakihi ( Nemadactylus macropterus ) is a demersal fish that supports valuable commercial, recreational, and customary fisheries in New Zealand. However, little is known about its stock structure. The population genetic structure, genetic diversity, and demographic history of N. macropterus were investigated using the hypervariable region one of the mitochondrial control region. 370 samples from 14 locations around New Zealand were collected. While weak genetic breaks were detected between Hawke's Bay and East Northland and between the west and east coasts of South Island, no clear genetic structure was detected for the overall New Zealand area (Ф ST = 0.002, P = 0.18), indicative of a panmictic genetic structure. N. macropterus display a high level of genetic diversity and appear to have a historically large and stable population with a long evolutionary history. Bayesian skyline analysis indicates that the historic population has gone through two expansions, likely caused by repeated glacial cycles during the second half of the Pleistocene. The addition of 15 king tarakihi samples ( Nemadactylus n.sp.) collected from the Three Kings Islands showed a clear genetic differentiation between the two morphotypes. These findings can inform the future management of N. macropterus and N . n.sp. to ensure a sustainable harvest.

Fish parasites can reflect environmental quality in fish farms - Gabriela Tomas Jerônimo; Matheus Gomes da Cruz; Elisabeth de Aguiar Bertaglia; William Eduardo Furtado; Maurício Laterça Martins (Reviews in Aquaculture, 2022)
In the aquatic environment, fish are subject to different pollutants and environmental variations that favour stress on animals, making them vulnerable to pathogens. Fish parasites are excellent biological indicators of environmental quality, as their parasitic population may increase or decrease in response to changes in water parameters and/or the presence of pollutants. Ectoparasites are considered excellent indicators of environmental quality because they have a monoxenic life cycle with high reproductive rates that have been responsible for the immediate response to changes in aquatic biota. In turn, parasites with a heteroxenous life cycle are also responsive to environmental variation because, with the mortality of intermediate hosts, their population can be easily changed. However, studies with endoparasites and their relation with the environment are more numerous, as they are accumulators of pollutants, especially trace elements, either via fish or through stages of development outside the host that also contribute to the accumulation of metals. Moreover, Digenea, Acanthocephala, Nematoda and Cestoda parasites can compete for trace elements that are bioavailable in the environment, as fish with a greater abundance of parasites have a lower concentration of toxic metals in their tissues. Furthermore, they have a high affinity for trace elements that are toxic to human and fish health (arsenic, mercury, lead and cadmium). This review is a comprehensive overview of the use of fish parasites as environmental sentinels and describes their potential as bioindicators of effect and accumulation, and evaluates their application in fish farms environments.

Harnessing the potentialities of probiotics, prebiotics, synbiotics, paraprobiotics, and postbiotics for shrimp farming - Joanna Xuan Hui Goh; Loh Teng‐Hern Tan; Jodi Woan‐Fei Law; Hooi‐Leng Ser; Kooi‐Yeong Khaw; Vengadesh Letchumanan; Learn‐Han Lee; Bey‐Hing Goh (Reviews in Aquaculture, 2022)
The shrimp farming industry is receiving increasing attention globally. However, extending the frontiers of the industry has been a challenge as high stocking density often increases susceptibility to diseases and compromises shrimp quality. There has been a huge adoption of bacterial‐derived additives in recent decades, particularly in Asia. Accumulating evidence demonstrates the modulatory effect of these functional additives on the animal gut microbiota composition, thus making them potential alternatives to antibiotics in controlling infectious diseases, such as acute hepatopancreatic necrosis disease (AHPND). These functional additives could be introduced in various forms, such as probiotics, synbiotics, paraprobiotics, and postbiotics. This article aims to critically review previous studies that investigated the effects of these bacterial derivatives, particularly on shrimp species. The surge of research in recent years indirectly attested to the immense potentialities of these functional additives. Generally, the introduction of bacterial derivatives not only helped in disease control but also demonstrated encouraging outcomes, including better survival rate, immune enhancement, and growth promotion effects. It is interesting to note that the effectiveness of probiotics extended beyond the viability of the bacteria, thus leading to concepts such as paraprobiotics and postbiotics. Although this is a relatively new research area with limited information, this review aims to consolidate available data and provide a comprehensive overview of the state of the art of this research arena. The challenges in each research domain were also discussed towards the end of this review to provide insights into potential future research niches.

Genetic improvement of giant freshwater prawn Macrobrachium rosenbergii : A review of global status - Bindu R. Pillai; Raul W. Ponzoni; Kanta Das Mahapatra; Debabrata Panda (Reviews in Aquaculture, 2022)
Giant freshwater prawn (GFP), Macrobrachium rosenbergii , is a tropical species widely cultured in several countries across the world. It has high market demand accompanied by attractive prices. The global farmed production of this species in 2018 was 237,124 tonnes (t) valued over 1.93 billion USD. Due to its importance in freshwater aquaculture, several countries have started genetic improvement programmes for this species with varying degree of success. The selective breeding programmes for M . rosenbergii were started rather late (in the mid‐nineties) compared with other aquaculture species such as salmon (1975), tilapia (1986) and rohu carp (1992). At present, genetic improvement programmes with this species are continuing in Vietnam, China, India, Thailand and Indonesia. In the majority of the breeding programmes, the major selection trait is growth rate. The heritability of growth rate (harvest body weight; HBW) ranged from 0.056 to 0.407. In most of the programmes, response to selection was moderate to high ranging from 4.4% to 11% per generation. Selection for faster growth has also brought correlated response of higher edible meat without detrimental effects on flesh quality attributes. There was low response per generation (1.1% per generation) in survival rate. The present paper reviews the selective breeding programmes for GFP being carried out in different countries with a focus on experiences gained and the problems faced in disseminating the improved strain. The challenges faced during the conduct and practical implementation of breeding programmes are discussed, and we outline research areas that could lead to improved productivity in this species.

Worldwide overview of reproduction, juvenile collection, spat production and cultivation of pen shells - Jorge Chávez‐Villalba; Felipe de Jesús Reynaga‐Franco; Francisco Hoyos‐Chairez (Reviews in Aquaculture, 2022)
Pen shells hold some potential for cultivation, but information on aquaculture activities is fragmentary, and no sustained or commercial production of any such species is currently in place. We reviewed information available worldwide on reproductive cycles, wild juvenile collection, spat production in hatcheries and cultivation systems for 45 pen shell species. We found information on the topics of interest for 15 species, Atrina maura and Atrina pectinata being the most studied. Reproductive cycles have been described for ten species, but size at first maturity has been reported only for A . maura and Pinna rugosa . Onion mesh bags and mosquito nets are the materials used for wild juvenile collection of most species. Nevertheless, seed collection has decreased for some species because of overexploitation, diseases or trawling that has severely impacted populations, so spat production in hatcheries is a fundamental aspect. Yet, hatcheries face challenges due to the high mortality of umbo larvae and during metamorphosis, and larvae produced by broodstock with overmature gonads. Market size individuals can be produced using culture methods currently available, but hatchery protocols and culture devices must be tailored specifically for pen shells. Reduced availability of wild spat and limited spat production in hatcheries are major constraints for developing and sustaining cultures. Studies on reproduction and spat production are necessary, as well as the implementation of protection measures and development of restoration plans for pen shell populations. Apparently, there is insufficient information available to foster the development of aquaculture, with tensions between preserving species and aquaculture programmes.

Bacteria in biofloc technology aquaculture systems: roles and mediating factors - Godwin Abakari; Xia Wu; Xi He; Lipeng Fan; Guozhi Luo (Reviews in Aquaculture, 2022)
The abundance of nitrogen compounds, phosphorous compounds and organic matter in biofloc technology (BFT) aquaculture systems creates an ideal medium for increasing microbial communities and load. The abundance of microbial DNA found in BFT aquaculture systems is hypothesised to be among the greatest in current aquaculture systems. Several factors mediate the bacterial diversity, relative abundance and dynamics in BFT systems. This review focusses on the bacteria in BFT aquaculture systems, their role as food for animals present in the culture and their various relationships with major nutrients. The analytical techniques available for determining bacterial integrity and function are reviewed along with the factors that affect microbial community structure, water quality and production performance. Future investigations to characterise bacteria in BFT aquaculture systems and their roles and mediating factors are suggested.

Systematic review of the odorous volatile compounds that contribute to flavour profiles of aquatic animals - Ben C. Jones; Melissa M. Rocker; Russell S. J. Keast; Damien L. Callahan; Hannah J. Redmond; Richard P. Smullen; David S. Francis (Reviews in Aquaculture, 2022)
The flavour of aquatic animal products is distinct from terrestrial foods, facilitating a competitive marketing advantage. However, the flavour of aquatic animals can also be highly variable. Importantly, differences are reported in the flavour of animals from aquaculture and wild‐capture systems. These differences can erode consumer acceptance of aquaculture products and reduce financial returns to producers. Mild ‘fish‐like’, ‘marine’, ‘crustacean‐like’, ‘seafood’ and ‘sweet’ odours are desirable. However, overt ‘fish‐like’, ‘fatty’ and ‘earthy’ odours are quality deficits and cause products to become unpalatable. Odorous volatile compounds are responsible for eliciting these characteristic odours. In this literature review, the odorous volatile compounds of 96 aquatic animal samples are reported, revealing 291 different compounds. Generalist compounds that are integral to the odour of aquatic animals are presented in addition to 86 compounds that elicit key characteristic odours. The influence of these compounds on aquatic animal flavour is explored and the specific factors likely to affect their manipulation in aquaculture products are discussed. The culture environment and diet are critical factors affecting volatile profiles of aquatic animals and are the variables that can be controlled by aquaculture producers. The information presented in this review can underpin the development of innovative aquaculture strategies that prevent environmental exposure of aquatic animals to unpalatable volatile compounds and facilitate the development of aquaculture diets that optimise the volatile profile of edible tissues.

Thirty years of rice‐crab coculture in China—Research progress and prospects - Jie Bao; Hongbo Jiang; Xiaodong Li (Reviews in Aquaculture, 2022)
Chinese mitten crab ( Eriocheir sinensis ) culture in rice paddy fields is a representative model of integrated agriculture‐aquaculture systems developed in China over the last 30 years. The economic and ecological benefits of rice‐crab coculture are significantly improved compared to those of rice monoculture. Under coculture conditions, rice provides shelter for crabs and improves the aquatic environment, while crabs eliminate pests and weeds, reduce the need for chemical fertilizers and pesticides, and stabilize rice production. At the same time, rice‐crab coculture helps protect biodiversity and reduce greenhouse gas emissions. An in‐depth study has led to the significant development of rice‐crab coculture technology in China and has established ecological breeding models with regional characteristics. These studies have established breeding industry standards for paddy field engineering, stocking mode, water quality control, rice management, feeding, pest control and breeding management. However, more research is needed to standardize rice field engineering specifications, optimize coculture modes, clarify crab nutritional needs, develop disease prevention and control methods, elucidate the operational mechanism of rice‐crab coculture and ascertain energy‐material exchange with the external environment. Eventually, rice‐crab coculture can be highly integrated to utilize the fewest resources while providing the greatest economic and environmental benefits. This review provides a theoretical reference for further research in the field of rice‐crab coculture, examining aspects such as development history, economic benefits, organisms in the system (rice, crabs, plankton, zoobenthos, weeds and microorganisms), internal and external environmental benefits, and the direction of future development.

Edwardsiella ictaluri : A systemic review and future perspectives on disease management - Vimbai Irene Machimbirike; Margaret Crumlish; Ha Thanh Dong; Javier Santander; Pongsak Khunrae; Triwit Rattanarojpong (Reviews in Aquaculture, 2022)
Edwardsiella ictaluri , a non‐zoonotic Gram‐negative bacterium, has been known to science for more than 4 decades. It was reported for the first time in 1979 in Ictalurus punctatus in the USA and later in Pangasianodon hypophthalmus and Pelteobagrus fulvidraco in Asia. Even though catfish species are more susceptible to E. ictaluri , other fish species are also affected, and up to 44 fish species in four continents are known to be susceptible. The diseases caused by E. ictaluri are known as enteric septicaemia of catfish (ESC) in channel catfish, bacillary necrosis of pangasius (BNP) in striped catfish, red head disease in yellow catfish and edwardsiellosis in tilapia. Outbreaks caused by E. ictaluri can cause up to 100% mortality resulting in substantive economic losses to the industry, threatening food security and undermining sustainability. Although efforts have been made to prevent and control this pathogen using vaccines, antibiotics, disease resistance selective breeding, functional feed ingredients, prebiotics and probiotics, and biosecurity measures, E. ictaluri is still causing health issues in different countries. Here, we provided with a comprehensive review that addressed the current knowledge of E. ictaluri bacteriological characteristics, epidemiology, pathogenesis, diagnosis, control and management. Furthermore, we also provided the future perspectives based on advanced technologies and biosecurity management in aquaculture to assist pathogen control and/or eradication.

A decision support tool for parasite management in fish aquaculture - Kate Suzanne Hutson; Allan James Mooney; Ingo Ernst; Alexander Karlis Brazenor; Max Scheel; Javier Atalah (Reviews in Aquaculture, 2022)
A decision support tool was developed to aid management of problematic parasites in marine fish aquaculture. The tool provides biologically relevant treatment intervals to interrupt the life cycle of ectoparasitic flatworms that occur in global kingfish and amberjack ( Seriola spp.) aquaculture. Temperature‐dependent life cycle parameters for the ‘skin flukes’, Benedenia seriolae and Neobenedenia girellae , and the ‘gill fluke’, Zeuxapta seriolae , were derived from published data and modelled using non‐linear regressions. Increasing temperatures shortened the duration of most life cycle parameters of all parasites. Salinity had no effect on the timing of life cycle parameters but limited hatching success in hypo‐ and hypersaline conditions. The tool, named BeNeZe after the first two letters of each parasite genera, enables rapid determination of treatment intervals for two consecutive medicinal immersion or ‘bathing’ treatments—the first to kill adult flatworms attached to fish and the second to prevent maturity of new parasite recruits. As temperature increases, the interval between treatments and the ‘window’ within which the second treatment should be applied is reduced. The tool can be used for multi‐species infections. The inclusion of parasite taxonomy, biology and behaviour as part of an integrated management strategy is reviewed. Available through an open access app, BeNeZe is intended to be applied in conjunction with farm biosecurity, surveillance, management measures and recognition of independent management units. BeNeZe can be used to reduce infection burdens, improve fish welfare and production and reduce treatment number and frequency.

Understanding asymmetrical malpigmentation in flatfishes and improvement measures for aquaculture - Bo Zhang; Changwei Shao; Songlin Chen; Baolong Bao (Reviews in Aquaculture, 2022)
Pleuronectiformes, an order known as flatfishes, is important in mariculture worldwide with the unique characteristic of body asymmetry, and thus has value in scientific research. Also, as an economically important species, flatfishes have great developing potential for industrial aquaculture. Their rapid growth, rich nutrition, delicious taste, and high‐quality protein are accepted and favoured by consumers all over the world. Due to large‐scale breeding and expanding production, however, different degrees of abnormal body colour flatfishes have emerged, which seriously affect commercial value of the fish, even reducing it by half; therefore, relevant research has been carried out. This article reviews how environmental factors affect body colour abnormalities and possible genetic mechanism of abnormal body colouration of flatfishes, summarizes the hypotheses of the mechanism of body colour asymmetry, and proposes the latest improvement measures obtained at the genomic screening level to prevent the occurrence of abnormal body colour. This review suggests the molecular mechanism of abnormal asymmetric distribution of body colour, suggests measures for avoiding malpigmentation in flatfishes, and provides a constructive theoretical reference for healthy development of the flatfish breeding industry.

Chinese abstracts (Reviews in Aquaculture, 2022)

Optimization of aquaculture sustainability through ecological intensification in China - Shuang‐lin Dong; Yun‐wei Dong; Ling Cao; Johan Verreth; Yngvar Olsen; Wen‐jing Liu; Qi‐zhi Fang; Yan‐gen Zhou; Li Li; Jing‐yu Li; Yong‐tong Mu; Patrick Sorgeloos (Reviews in Aquaculture, 2022)
As the world's leading producer of farmed aquatic food products, China faces great uncertainty concerning the further sustainable development of its aquaculture industry due to high and increasing pressure from environmental and resource constraints. To realize truly sustainable development, it is imperative to establish an evaluation system that integrates social, economic, environmental and resource criteria, and optimizes aquaculture systems through a holistic approach. Here, we used analytical hierarchy processes combined with expert judgment and objective data to assess the sustainability of 10 major aquaculture production systems (APSs) in China. Based on the evaluation results, we propose the ecological intensification of aquaculture systems (ELIAS), rationally integrating anthropogenic inputs with aquaculture ecosystem services, to improve the sustainability of APSs. The holistic evaluation system and ELIAS are fundamental and critical for the future development of aquaculture in China and globally.

Cover Image, Volume 14, Issue 3 - Joanna Xuan Hui Goh; Loh Teng‐Hern Tan; Jodi Woan‐Fei Law; Hooi‐Leng Ser; Kooi‐Yeong Khaw; Vengadesh Letchumanan; Learn‐Han Lee; Bey‐Hing Goh (Reviews in Aquaculture, 2022)
The cover image is based on the Review Article Harnessing the potentialities of probiotics, prebiotics, synbiotics, paraprobiotics, and postbiotics for shrimp farming by Joanna Xuan Hui Goh et al., https://doi.org/10.1111/raq.12659 image

The utilisation of European processed animal proteins as safe, sustainable and circular ingredients for global aquafeeds - Stephen L. Woodgate; Alex H. L. Wan; Finnian Hartnett; Robert G. Wilkinson; Simon J. Davies (Reviews in Aquaculture, 2022)
The global increase in seafood demand has resulted in significant growth in aquaculture production in a wide range of aquatic species. Consequently, this has led to an industry‐wide need to find sustainable feed ingredients that would meet the nutritional requirements used in aquafeeds. The associated dependency on plant by‐products as the major alternatives has brought concerns to aquaculture through associated carbon footprint, increase deforestation and arable land use to meet the demands of plant proteins and oils, and the constraining effects of plant by‐products has on farmed aquatic animal growth and health. Animal by‐products (ABPs) are produced as a direct consequence of terrestrial animal production and the associated meat processing industries. The link between feeding meat and bone meal (MBM) and bovine spongiform encephalopathy (BSE) outbreak in Europe during the 1980s resulted in a ban of its use animal feeds. This led to a radical overhaul of the rendering industry, including the use of only low‐risk ABP and the development of rendering processes to reduce the risk of prions that causes BSE to enter the food chain. The resulting processed animal proteins (PAPs) are considered safe to be used in farmed animal feeds. This review examines how ABP production has changed due to the BSE outbreak, leading to the current commercially available PAP products for aquafeed use. We evaluated how these products can be effectively used as viable protein sources in aquaculture and examine their limitations and the potential advancements that could lead to a more circular food production system.

Aquaculture research and social media: A powerful tool for dissemination or white noise? - Thomas S. Mock; Fang Qiao; Giovanni M. Turchini (Reviews in Aquaculture, 2022)

Portuguese‐Brazilian abstracts (Reviews in Aquaculture, 2022)

Spanish abstracts (Reviews in Aquaculture, 2022)

Compensatory growth: Fitness cost in farmed fish and crustaceans - Clara Py; Regina Elizondo‐González; Alberto Peña‐Rodríguez (Reviews in Aquaculture, 2022)
Feed restriction in fish and crustaceans is gaining interest due to its unusual acceleration of growth after a feed deprivation period. This phenomenon, known as compensatory growth, allows deprived organisms to reach the weight of never‐stressed counterpart organisms. Since feed is the major economic and ecological burden of fish and crustaceans farming, succeeding to reduce its quantity without loss of production may enhance a sustainable aquaculture development. A wide variety of restriction/feeding protocols, involving differences in nature, duration and intensity, have been tested on aquatic organisms. However, not all of them lead to optimal compensatory growth. Furthermore, before extending this practice to industrial setting, it is essential to assess physiological costs associated with both food restriction and compensatory growth. Indeed, although fish and crustaceans appear to be tolerant to dietary restriction, it involves metabolic, digestive, oxidative and immune changes. Nevertheless, return to basal values is not always achieved through refeeding. Compensatory growth has been observed and described in many taxa; however, physiological mechanisms during this process are poorly understood. On the other hand, the acceleration of growth itself appears to generate physiological consequences in organisms, particularly through the generation of oxidative stress. This review provides an overview of the fitness consequences associated with dietary restriction and the subsequent enigmatic compensatory growth in fish and crustaceans.

Epiphytism, diseases and grazing in seaweed aquaculture: A comprehensive review - Durga Prasad Behera; Kapilkumar N. Ingle; Doniya Elze Mathew; Asmita Dhimmar; Harshal Sahastrabudhe; Sunil Kumar Sahu; M. Gobala Krishnan; Pramod. B. Shinde; M. Ganesan; Vaibhav. A. Mantri (Reviews in Aquaculture, 2022)
Seaweeds are macroscopic forms of phylogenetically diverse assemblage of marine algae that grow in oceans, thriving among profoundly harsh environmental conditions. They are cultivated in many maritime nations primarily for edible applications; besides hydrocolloid extraction is the second largest domain of utility for this renewable biomass. The farming practices have been traditionally evolved in different Southeast Asian countries. Nevertheless, advancement in the knowledge about their life‐history traits and control over reproduction has paved ways for commencement of large‐scale commercial farming. Food and Agriculture Organisation of United Nations reported the availability of 35.8 million tons of seaweed biomass globally of which 97% accounted for farming. Although cultivation is on the rise due to relevant to social gains, epiphytic infestation, diseases and grazing have been identified as leading causes that result in substantially lower yield, deteriorated quality of product and skewed economics. Epiphytes may considerably impact the interaction of seaweed hosts with other beneficial communities also. Epidemiological studies in natural seaweed populations are scarce and this makes the understanding of the cross‐talk involving host specificity, and their role obscure. An overview of the diversity of epiphytes, understanding of mechanism of action, factors responsible, chemistry behind their interaction will help in deciphering the solutions to overcome infestation. A comprehensive report of seaweed epiphytism, diseases and grazing from the aspects of host–epiphyte interaction and their resultant consequences is presented along with the studies on economic impacts. The role of multi‐omics approaches in delineating seaweed epiphytic interactions is also included.

Systematic review and meta‐analysis of production performance of aquaculture species fed dietary insect meals - Hung Quang Tran; Tram Thi Nguyen; Markéta Prokešová; Tatyana Gebauer; Hien Van Doan; Vlastimil Stejskal (Reviews in Aquaculture, 2022)
The present work employed a systematic review and meta‐analysis to quantify the overall effects of various types of insect meal on special growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER) of aquatic animals. A total of 107 studies published from 1990 to 2021, targeting 23 freshwater and 17 marine fish species, employing 17 insect species as a replacement for fishmeal, was compiled. Overall, a significantly higher Hedges’ g value for SGR and lower FCR was found in aquatic animals fed dietary larval defatted mealworm Tenebrio molitor and pupal full‐fat silkworm Bombyx mori compared with fishmeal diet. The majority of dietary insect meals had a negative linear correlation with Hedges’ g of growth performance, except larval fly Chrysomya megacephala , which had a positive linear relationship, and of prepupal defatted black soldier fly Hermetia illucens , which had a negative quadratic relationship. Some insect meals, including G . bimaculatus , adult grasshoppers of Oxya fuscovittata and Zonocerus variegatus and larval full‐fat Cirina butyrospermi , supported adequate growth of aquatic animals at plausible inclusion levels. At as low as 2.2%, insect‐derived chitin supported growth performance and improved feed utilization of marine fish species. In the quest to minimize fishmeal in aquafeeds, insect meal holds enormous potential but is not the sole option; rather, integrating insect meal and novel/conventional materials is more strategic. The present study lays the groundwork for further multidisciplinary considerations for the effective use of insect meal as an alternative aquafeed protein with the goal of long‐term sustainability.

Issue Information (Reviews in Aquaculture, 2022)

Cover Image, Volume 14, Issue 3 - Shuang‐lin Dong; Yun‐wei Dong; Ling Cao; Johan Verreth; Yngvar Olsen; Wen‐jing Liu; Qi‐zhi Fang; Yan‐gen Zhou; Li Li; Jing‐yu Li; Yong‐tong Mu; Patrick Sorgeloos (Reviews in Aquaculture, 2022)
The cover image is based on the Review Article Optimization of aquaculture sustainability through ecological intensification in China by Shuang‐lin Dong et al., https://doi.org/10.1111/raq.12648 image

The potential role of medicinal mushrooms as prebiotics in aquaculture: A review - Kannan Mohan; Durairaj Karthick Rajan; Thirunavukkarasu Muralisankar; Abirami Ramu Ganesan; Kasi Marimuthu; Palanivel Sathishkumar (Reviews in Aquaculture, 2022)
Aquaculture industry is one of the major food‐producing sectors in the world that provide nutritional food security for mankind. Fish and crustacean farmers are facing various challenges in treating the rapid spread of infectious diseases in recent times. Numerous strategies, including antibiotics, disinfectants, and other antimicrobial agents, have been applied to protect the cultivable aquatic animals from infectious diseases. These applications lead to the development of antimicrobial resistance, toxicity, and the accumulation of antibiotic residues in cells and organelles of the cultivable edible organisms and the environment. The use of naturally derived compounds, polysaccharides, and functional metabolites has gained immense attention among aquaculturists. Mushrooms and their nutraceutical components have been widely used in various sectors, including food, pharmaceutical, poultry, and aquaculture industries, for their non‐toxic and eco‐friendly properties. To date, there are several reports available on edible and medicinal mushrooms as a dietary ingredient for fish and decapod crustacean culture. The mushroom products such as mycelia, stalk, dry powder, polysaccharides, and extracts have been utilized in aquaculture as growth promoters and immunostimulants, improving the digestive enzyme activity, antimicrobials, and improving the health status of cultivable aquatic animals. This present review elucidates the effectiveness of mushrooms and mushroom‐derived compounds as prebiotics in aquaculture. The challenges and future perspectives of mushroom‐derived bioactive molecules have been discussed in this review.

Arabic Abstracts (Reviews in Aquaculture, 2022)

Quantifying habitat provisioning at macroalgal cultivation sites - Sophie Corrigan; Andrew Ross Brown; Ian G. C. Ashton; Dan A. Smale; Charles R. Tyler (Reviews in Aquaculture, 2022)
Macroalgal cultivation is expanding rapidly, and promises to contribute significantly towards future food and energy security, sustainable livelihoods, ecosystem services and habitat provisioning for a range of associated organisms globally. Habitat provisioning underpins biodiversity and ecosystem structure and functioning, supports many ecosystem services and has possible benefits to other marine industries, including enhancement of commercial fish stocks. In macroalgal cultivation, however, only recently has habitat provisioning started to be assessed at a local scale (within a farm's footprint) and with a range of different approaches. This review evaluates techniques used to quantify habitat provisioning in and around macroalgal cultivation sites, for species ranging from microorganisms to megafauna, and outlines recommendations to enable a more comprehensive ecological valuation of macroalgal cultivation in the future. The majority of information on biodiversity associated with macroalgal cultivation is associated with quantifying biofouling or pest organisms, rather than the contribution of colonising species to healthy ecosystem functioning. We suggest how better monitoring of macroalgal cultivation could enable an ecosystem approach to aquaculture (EAA) in the future. To achieve this, we highlight the need for standardised and robust methods for quantifying habitat provisioning that will enable assessment and monitoring of macroalgal cultivation sites of varying scales and within different regions and environmental settings. Increased evidence for the potential habitat value of macroalgal cultivation sites will help inform and shape marine legislation, licencing and certification for macroalgal farmers and potentially reduce marine user conflicts, helping the industry to continue to grow sustainably using EAA.

Shrimp immune response: A transcriptomic perspective - Carlos Fajardo; Gonzalo Martinez‐Rodriguez; Benjamin Costas; Juan Miguel Mancera; Sergio Fernandez‐Boo; Hectorina Rodulfo; Marcos De Donato (Reviews in Aquaculture, 2022)
During the last 15 years, a significant amount of data related to the crustacean immune system has been generated, mainly led by the advances made in the field of transcriptomic analysis through massive mRNA sequencing technology. In order to shed new light on the genes and metabolic pathways associated with the immune system in shrimp species, we have carried out a meta‐analysis using the current literature and the Sequence Read Archive (SRA) database of the National Center for Biotechnology Information (NCBI), which has 1195 published transcriptomic data sets until 31 December 2020, from different tissues and 14 Penaeus species. The transcriptomic analyses published so far have explored the effects of the challenge from viral and bacterial pathogens, as well as abiotic stressors, such as ammonia, temperature, salinity, oxygen deprivation and pH. They have also explored the effect of dietary factors and beneficial microbes (pre‐ and probiotics) in the immune response. In order to harness the vast amount of information available, multidisciplinary efforts have to generate better genomic tools to overcome the complexity of the genome and to implement the knowledge gained into commercial applications for the improvement of the culture conditions, adaptation of more sustainable feeds and producing strains showing more resilience/tolerance to diseases.

Metabolic reprogramming in crustaceans: A vital immune and environmental response strategy - Zhongyan Wang; Yueling Zhang; Defu Yao; Yongzhen Zhao; Ngoc Tuan Tran; Shengkang Li; Hongyu Ma; Jude Juventus Aweya (Reviews in Aquaculture, 2022)
Most host organisms undergo metabolic changes in response to pathogens, environmental cues or simply to boost their immunity. Metabolic modulation has therefore been exploited by both host and pathogens to outwit the other during host–pathogen interactions. Recent studies have revealed that a growing number of metabolites and metabolic processes in crustaceans are crucial in host–pathogen interactions. Here, we reviewed recent work on metabolic changes during immune response of crustaceans and the metabolic reprogramming that takes place in the host induced by pathogens, environmental cues or as a host strategy to withstand these changes or clear the pathogen. In aquaculture crustaceans, limited studies exist on this subject; hence, we will also highlight themes for possible future research on metabolite reprogramming and how this strategy can be leveraged to improve sustainable aquaculture and enhance crustaceans’ response to pathogens and environmental changes.

Cannibalism mitigation in striped murrel, Channa striata , with hatchery seed weaned on pellet diet: A review - Sudhir Raizada; Anurag Rawat; Prem P. Srivastava; Kuldeep K. Lal (Reviews in Aquaculture, 2022)
Striped snakehead is one of the important food fish of high commercial value due to preference for its meat quality, therapeutic and antinociceptive properties. The species is distributed in many countries in South Asia to South‐East Asia. The current production of the species is largely contributed from the capture fisheries as there are several inherent problems associated with its farming. The major bottlenecks for aquaculture production are insufficient knowledge on reproductive biology, captive breeding, higher mortalities of larvae in nursing phases, intracohort cannibalism and non‐acceptance of artificial diet. The available information on these issues is sparse, often anecdotal and needs comprehensive up‐scaling. To address this gap, this review compiles the available information on this species to have a better understanding of reproductive biology, captive spawning, larval rearing, cannibalism mitigation, nursery rearing of seed in different rearing systems, and most important being weaning seed on the artificial diet so that this species could be cultured on artificial diets in the grow‐out systems. It is expected that this review would provide useful information for the production of feed‐weaned hatchery‐seed.

Potential application of bacteriocins for sustainable aquaculture - Ashwath Nayak; Indrani Karunasagar; Anirban Chakraborty; Biswajit Maiti (Reviews in Aquaculture, 2022)
The emergence and prevalence of bacterial pathogens in freshwater aquaculture systems is a growing concern as the economic losses associated with diseases are mounting and impacting the fishery sector. One way of controlling fish mortality and morbidity is using bacteriocin‐secreting probiotics, which are generally considered safe without any adverse effects that usually accompany other treatment strategies. Understanding the mode of action of bacteriocin on pathogens is vital for considering them suitable for application as a prophylactic in aquaculture. Although several measures such as antibiotic treatment, chemotherapy, vaccination, etc., are available, though not without concerns, these methods have limitations for field‐level applications since they result in several adverse effects both for the animals and the aquatic environment affecting several species in the food chain. In this situation, the use of bacteriocin can be an excellent alternative to minimize the disease burden in freshwater aquaculture if delivered appropriately. Here, we provide an update on the various bacteriocins and their mode of action against important pathogens encountered in aquaculture.

The regulation of shrimp metabolism by the white spot syndrome virus (WSSV) - Ramya Kumar; Jiun‐Yan Huang; Yen‐Siong Ng; Cong‐Yan Chen; Han‐Ching Wang (Reviews in Aquaculture, 2022)
For more than three decades, infectious diseases have been one of the major causes of economic losses in the global shrimp industry. One of the deadliest of the shrimp pathogens is white spot syndrome virus (WSSV), which causes mass mortality in farmed shrimp. Various aspects of WSSV pathogenicity have been studied, but in this review, we will focus only on one of them, namely metabolic reprogramming. WSSV’s modulation of host metabolism affects glycolysis, the tricarboxylic acid (TCA) cycle, glutaminolysis and lipid metabolism. Several signaling pathways are involved in this regulation, including JAK‐STAT, PI3K‐AKT‐mTOR, MAPK and Ras‐Raf‐MEK, with the PI3K‐Akt‐mTOR pathway in particular playing a critical role in activating the WSSV‐induced Warburg effect. Taken together, these changes benefit the virus by facilitating WSSV replication. In this review, we summarize current knowledge regarding the metabolism‐related aspects of WSSV pathogenesis, and discuss the mechanisms by which this virus reprograms its host's metabolic pathways. A deeper understanding of these pathways, key metabolic enzymes and signaling mechanisms is potentially important for the development of effective anti‐WSSV strategies.

Highly diluted bioactive compounds in marine aquaculture: A potential alternative for sustainable production - Jesús Antonio López‐Carvallo; José Manuel Mazón‐Suástegui; Guadalupe Fabiola Arcos‐Ortega; Miguel Ángel Hernández‐Oñate; Dariel Tovar‐Ramírez; Fernando Abasolo‐Pacheco; Milagro García‐Bernal (Reviews in Aquaculture, 2022)
Highly diluted bioactive compounds (HDBC) and highly diluted immunomodulatory compounds (HDIC) are treatments that cover a wide variety of concentrations, starting from molar to yoctomolar concentrations or even lower where the presence of nanoparticles has been detected. The prophylactic use of these compounds has improved nutrition, growth, overall condition, defence mechanisms regulation and increased marine organism survival during challenge against pathogens. The HDBC used in marine organisms are formulated from Vibrio spp. lysates, sodium metasilicates, phosphoric acid and highly diluted drugs for humans as Silicea terra ® , Phosphoricum acidum ® , Passival ® and VidatoX ® , as well as homotoxic Heel ® complexes. Because HDBC are innocuous, inexpensive and easy to use by immersion or ingestion, they have been proposed as a potential sustainable alternative to improve marine organism production under hatchery conditions and reduce the use of chemotherapy, including antibiotics and disinfectants. Nonetheless, articles documenting their mode of action (biological process and metabolic pathways activated) are scarce. Some studies have proposed that certain HDBC activate the sentinel system of marine organisms, such as non‐self‐recognition and endocytosis mechanisms without completely activating the immune defence mechanisms. This contribution brings a new insight on increasing productivity and cost effectiveness during hatchery operations and at the same time strengthening the immune system response and survival of marine organisms against infections. Therefore, this review discusses and analyses published results of HDBC in species of commercial importance worldwide and also emerging species of interest for aquaculture reared in Mexico.

Nutrient retention efficiencies in integrated multi‐trophic aquaculture - Marit A. J. Nederlof; Marc C. J. Verdegem; Aad C. Smaal; Henrice M. Jansen (Reviews in Aquaculture, 2022)
One of the bottlenecks for commercial implementation of integrated multi‐trophic aquaculture (IMTA) is the difficulty in quantifying its environmental performance. We reviewed a large body of literature to determine the variability in nutrient dynamics within different IMTA systems (open sea‐cages, land‐based flow‐through and recirculating aquaculture systems), with the aim to provide a generic framework to quantify nutrient retention efficiencies in integrated aquaculture systems. Based on the eco‐physiological requirements of the cultured species, as well as the response of “extractive” species to waste from “fed” species, the maximum retention efficiency was defined for a conceptual four‐species marine IMTA system (fish–seaweed–bivalve–deposit feeder). This demonstrated that 79%–94% of nitrogen, phosphorus and carbon supplied with fish feed could theoretically be retained. In practice, however, various biological and environmental factors may limit retention efficiencies and thereby influence the bioremediation of IMTA systems. These biological (waste production, stoichiometry in nutrient requirements) and environmental (temporal and spatial connectivity) factors were therefore evaluated against the theoretical reference frame and showed that efficiencies of 45%–75% for closed systems and 40%–50% for open systems are more realistic. This study is thereby the first to provide quantitative estimates for nutrient retention across IMTA systems, demonstrating that a substantial fraction of nutrients released from fish culture units can be retained by extractive species and subsequently harvested. Furthermore, by adapting this framework to the design and the condition prevailing for a specific IMTA system, it becomes a generic tool to analyse the system's bioremediation potential and explore options for further improvement.

Environmental enrichment increases aquatic animal welfare: A systematic review and meta‐analysis - Zonghang Zhang; Lijia Gao; Xiumei Zhang (Reviews in Aquaculture, 2022)
With the rapid development of aquaculture and the gradual decrease in fishery resources, aquatic animal welfare (AAW) has received increasing attention from animal protection organisations, government departments, biologists, fish culturists and consumers. Although environmental enrichment (EE) can potentially benefit AAW, the relevant results are sharply mixed, and the drivers for these discrepancies are largely unclear. In this study, we conducted a series of meta‐analyses to overcome this knowledge gap. We firstly compiled a full data set, consisting of 1171 effect sizes from 147 studies across 82 species and then performed a multilevel mixed‐effects model to evaluate the overall effect size and conduct the subsequent meta‐regression analyses. Overall, our results showed that aquatic animals from a physically enriched environment had significantly improved AAW compared with their counterparts from barren environments. For moderators, specific welfare traits, animal taxa, animal stages, enrichment types and enrichment colours showed strong positive EE effects on AAW. Subsequently, we constructed a fish data set and reran the meta‐analysis, yielding results substantially similar to those obtained using the full data set. Finally, we performed a multi‐model inference to identify the importance ranking of potential moderators. Results showed that enrichment type, animal taxon and welfare category are the best moderators of the direction and magnitude of EE effects on AAW. These results provide insights into the possible drivers of EE effects on aquatic animals with important implications for aquaculture, fisheries, conservation, research and aquarium, providing evidence‐based guidance for future animal welfare theories and practices.

Effects of point source discharges on common bully ( Gobiomorphus cotidianus ) along the Waikato River, New Zealand - David W. West; Nicholas Ling; Brendan J. Hicks; Michael R. van den Heuvel; Louis A. Tremblay (New Zealand Journal of Marine and Freshwater Research, 2022)
The common bully ( Gobiomorphus cotidianus ) was used as a bioindicator to assess the impacts of geothermal, bleached kraft mill effluent (BKME), sewage, and thermal discharges in the Waikato River, Northern New Zealand. A range of morphological and physiological parameters were measured to assess fitness in fish sampled upstream and downstream from these point sources. Isotopic signatures gave evidence that fish were resident at sites and showed a gradient corresponding to site‐specific sources of carbon and nitrogen along the river. There were changes in the size range and age structure of the populations but, no physiological responses were detected. Limited impacts were observed on common bully health at individual discharge sites, or downstream where the river showed gradual deterioration in water quality, particularly nutrient enrichment, and increased turbidity. Despite the gradual deterioration in water quality no concomitant cumulative impacts were observed in common bully. Responses were largely local in nature, responding to point‐source discharges. Population responses at the geothermal and BKME discharge sites warrant further study to investigate possible effects on fish recruitment.

Cetacean sighting records in the New Caledonia Basin, Tasman Sea, New Zealand - Katharina J. Peters; Karen A. Stockin (New Zealand Journal of Marine and Freshwater Research, 2022)
The distribution of marine mammal species in many areas remains poorly understood, especially as observations for some taxa are rare and large‐scale surveys are time consuming and extremely costly. Here, we present 36 records of 7 cetacean species ( Balaenoptera brydei , B. musculus subspp., Delphinus delphis , Globicephala sp., Grampus griseus , Physeter macrocephalus , Pseudorca crassidens ) in the New Caledonia Basin, Tasman Sea, along with their associated biological and environmental data. Data were derived from a platform of opportunity during a seismic survey that ran between December 2015 and March 2016, inclusively. The two most frequently encountered species were sperm whales ( Physeter macrocephalus , 13 sightings, 5 acoustic detections) and blue whales ( Balaenoptera musculus subspp., 8 visual detections). All encountered species are known to occur in New Zealand waters at least occasionally, based on historical sightings and stranding records. However, data presented here are the first cetacean records for this specific area and demonstrate that seismic vessels can act as a platform of opportunity for studying cetacean distribution in poorly accessible areas. Such data will aid future research efforts including species distribution models on cetaceans in the South Pacific.

Influence of habitat on meiofaunal abundance and distribution in a New Zealand temperate estuary - Shaneel S. Sharma; Andrea C. Alfaro; Kathleen A. Campbell (New Zealand Journal of Marine and Freshwater Research, 2022)
Meiofaunal assemblages are often overlooked, yet they are important ecological components of estuarine ecosystems. To evaluate variations in meiofaunal communities in estuarine habitats, we conducted a comprehensive analysis of meiofaunal density, distribution and relationships with environmental parameters in a mangrove‐dominated ecosystem at Mangawhai, Northern New Zealand, in summer (March) and winter (October), 2013. Five habitat types were studied including mangrove stands, pneumatophore zones, sandflats, mudflats and saltmarshes. In addition, data were recorded for sediment grain size, organic content, and primary benthic productivity (chlorophyll a). Twelve major taxa were identified, with meiofaunal densities ranging between 269 and 8090 ind. 10 cm −2 . Highest abundances were found in fine‐grained organic‐rich sediments compared to coarse‐grained organically poor sediments; the former were generally associated with mangroves stands and pneumatophore zones. Nematodes dominated all observed habitats. Foraminifera ranked second in fine‐grained organically rich sediments, whereas copepods ranked second in coarser‐grained sediments. Results suggest that meiofaunal taxonomic abundance and distribution are highly sensitive to local physical and biological parameters (e.g. sediment grain size, organic content, benthic primary productivity). The findings revealed that environmental characteristics have an important influence within this temperate estuary.

The influence of topography and land use on hydrological and nutrient dynamics in two Andean streams from Northern Patagonia - Alejandro Sosnovsky; Mailén Elizabeth Lallement; Magalí Rechencq; Eduardo Enrique Zattara; María Valeria Fernández; Sergio Leiva; María José Suárez; Romina Daga; Rodolfo Juan Carlos Cantet (New Zealand Journal of Marine and Freshwater Research, 2022)
Fluvial dynamics are driven by multiple environmental factors and scales. Studies coupling hydrological and nutrient dynamics of mountain streams are almost non‐existent in the Northern Patagonian region; which is characterised by a temperate‐cold climate. We studied two adjacent streams with contrasting drainage basins: Casa de Piedra (41°07′30.11″S 71°27′13.16″W), which originates in a small mountain lake and runs through pristine landscapes, and Gutiérrez (41°09′36.18″S 71°24′37.19″W) that originates in a large piedmont lake and runs through an anthropized landscape. The streams displayed contrasting hydrological and nutrient dynamics. Casa de Piedra had higher discharge flashiness with shorter response delays to precipitation. Whereas the hydrology of Gutiérrez was buffered by the upstream lake, its nutrient exports were not. Differences observed in quality and timing in the export of coarse particulate organic matter and levels of phosphorus and nitrogen are explained by human activities affecting Gutiérrez but not Casa de Piedra. Moreover, the ratio of nitrogen:phosphorus suggests that phosphorus may be the limiting nutrient in the future, at the more densely populated basin. To summarise, Northern Patagonian streams flowing under marked geological and climate similarities, display stark differences in dynamics of their adjacent basins due to differences in topography and land use.

Comparison of bathyscope and snorkelling methods for iwi monitoring of kākahi ( Echyridella menziesi ) populations in the shallow littorals of Lake Rotorua and Rotoiti - Siobhan H. Nuri; Ian A. Kusabs; Ian C. Duggan (New Zealand Journal of Marine and Freshwater Research, 2022)
Kākahi ( Echyridella spp.) are freshwater cultural keystone species in New Zealand; they represent a valuable mahinga kai (species used as a food) resource and have high cultural significance to Māori, particularly to the Te Arawa and Ngāti Tūwharetoa iwi (tribal groups). Population densities of kākahi are thought to have declined in many locations in New Zealand, and accurate assessment methods are thus required to monitor changes in populations. A bathyscope method is currently used by iwi to monitor kākahi populations in lakes Rotorua and Rotoiti. It is unclear, however, how accurate this method is for determining kākahi abundance changes compared to underwater methods such as snorkelling. Comparisons at seven sites in Lake Rotorua and three sites in Lake Rotoiti show that significantly fewer kākahi are observed using a bathyscope relative to snorkelling ( p

Congruence in stable isotope values among two sympatric freshwater mussel species in northern New Zealand streams - Kevin J. Collier; Michele Melchior (New Zealand Journal of Marine and Freshwater Research, 2022)
We measured δ 15 N, δ 13 C, and percent carbon (C) and nitrogen (N) on foot and remaining soft tissue of the two native freshwater mussel species Echyridella aucklandica and E. menziesii (Hyriidae: Unionida) from three Waikato, northern New Zealand, streams to investigate differences among sites, sexes and species. Mean differences in δ 15 N and δ 13 C between foot and remaining soft tissue (mainly guts, gills and gonads) were 15 N and δ 13 C displayed marked differences among sites for both species, with δ 15 N variations consistent with the level of catchment land‐use intensification. Variation in δ 13 C and δ 15 N among replicate mussels was low indicating few individuals are required to precisely characterise isotope signatures of local populations. The lack of evidence of trophic resource partitioning among species, and consistent differences in isotope ratios between sites, suggests that the more widespread and abundant E. menziesii may provide an effective baseline integrator of catchment activities that alter carbon supplies and nitrogen sources.

Distribution of little penguins ( Eudyptula minor ) along the greater Kaikōura coastline, New Zealand - Chloe Paulet Cargill; Alastair Gordon Judkins; Jody Suzanne Weir (New Zealand Journal of Marine and Freshwater Research, 2022)
The identification and subsequent protection of suitable breeding habitat for little penguins ( Eudyptula minor ) is restricted by data deficiency across large stretches of the species range. For example, presence/absence data is lacking for much of the Canterbury coast, mainland New Zealand. In October 2019, a Protected Species Detection Dog was used to conduct the first comprehensive survey for E. minor along the greater Kaikōura coastline. The principal objectives were to locate and map the distribution of sites utilised by E. minor between Waipapa Bay and the Conway River, characterise areas of suitable breeding habitat and identify ‘little blue’ and ‘white‐flippered’ morphotypes. Eudyptula minor were located within just 0.7% of a coastal stretch measuring c. 75 km. A single breeding colony was located in severely fragmented habitat on the southern face of the Kaikōura Peninsula, South Bay. The Detection Dog gave positive indications at six further isolated sites in sheltered bays, including two active nests on the northern faces of Spy Glass Point (Piripaua) and the Kaikōura Peninsula. We highlight the importance of the breeding colony at South Bay, Kaikōura, and recommend the protection of existing habitat as a priority for the survival of E. minor along the greater Kaikōura coastline.

Aquatic disease in New Zealand: synthesis and future directions - Henry S. Lane; Cara L. Brosnahan; Robert Poulin (New Zealand Journal of Marine and Freshwater Research, 2022)
Dedicated studies on aquatic disease in New Zealand began in 1974, inspired by a developing aquaculture industry. Since then, two main aquatic disease study areas have emerged: (1) aquatic disease ecology and (2) diseases of commercial species. Progress over the past 20‐years has been made by only a small number of researchers and aquatic disease in New Zealand has not received much attention from the wider marine science community. In 2020, the aquaculture industry continues to grow, and disease remains a threat to the industry's viability. However, additional factors such as climate change, invasive species, and pollution, have emerged as future threats for aquatic disease in wild and farmed populations, which are currently understudied. Here, we provide a review of studies on aquatic disease ecology and commercial species carried out in New Zealand. We also present how climate change, pollution and invasive species could influence future aquatic disease dynamics and identify where future research effort is required to address knowledge gaps. The emergence of consequential aquatic diseases overseas highlights wider attention across marine science disciplines is needed to progress and diversify aquatic disease studies in New Zealand.

Observations of salinity, flushing time and dispersion in the Waitemata Estuary - Zheng Chen; Melissa M. Bowen (New Zealand Journal of Marine and Freshwater Research, 2022)
The physical behaviour of estuaries controls the transport of substances from freshwater to the ocean. We conducted the first investigation of salinity distribution and its response to spring‐neap tides and freshwater flow rates in the Waitemata Estuary, and estimated several estuarine parameters. Four surveys were conducted: two surveys were conducted in summer during spring‐tide, low flow and neap‐tide, high flow conditions and two in June during spring‐tide, high flow and neap‐tide, low flow conditions. The vertical and longitudinal salinity variations were measured with shipboard surveys and river flow data were provided from gauged stations. We found the Waitemata Estuary can be classified as a well‐mixed estuary due to the combination of strong tidal currents and weak river flow. Highwater slack stratification can reach 0.5 psu over 10 m during times of weak tidal mixing (neap tides) and with increased freshwater flows after a storm. The estimated freshwater flushing time varied from a week to a month. Dispersion coefficients varied from 50 to 150 m 2 s −1 on average, depending on river flows and the location along the channel. Using the Simpson number and historical river flows, we expect stronger stratification could develop in the upper estuary during high flows, temporarily creating a partially‐mixed estuary.

Understanding antimicrobial peptides and combatting antimicrobial resistance problems - Pin Nie (Reviews in Aquaculture, 2022)

Spanish abstracts (Reviews in Aquaculture, 2022)

Chinese abstracts (Reviews in Aquaculture, 2022)

Arabic abstracts (Reviews in Aquaculture, 2022)

Portuguese‐Brazilian abstracts (Reviews in Aquaculture, 2022)

Issue Information (Reviews in Aquaculture, 2022)

Autogenous vaccination in aquaculture: A locally enabled solution towards reduction of the global antimicrobial resistance problem - Andrew C. Barnes; Oleksandra Rudenko; Matt Landos; Ha Thanh Dong; Angela Lusiastuti; Le Hong Phuoc; Jerome Delamare‐Deboutteville (Reviews in Aquaculture, 2022)
Antimicrobial resistance is a global public health crisis with attention focussed on food supply as part of the ‘One Health’ integration of veterinary, environmental and public health. Aquaculture has been the fastest growing livestock sector in recent decades and is critical to nutritional security in many low‐ and middle‐income countries (LMIC). With ready access to antibiotics and limited availability of veterinary support, disease control with antibiotics is poorly informed, often unrecorded and high in many countries where aquaculture growth is fastest. Vaccination of fish in LMIC with locally produced autogenous vaccines against bacterial diseases may provide a locally driven, cost‐effective means of reducing antibiotic use, replicating the successes achieved during the growth of Norway's aquaculture industry. Autogenous vaccines, as part of an informed veterinary health programme, have several advantages in terms of intellectual property, efficacy and flexibility. We consider access to fish vaccines in example countries of high aquaculture importance, including Thailand, Vietnam and Indonesia. We contrast the success of antimicrobial reduction in Norwegian salmon aquaculture with the high antibiotic use in the Chilean industry where vaccines are available, finding that regulation, planning, husbandry and environmental problems may increase disease incidence and severity. We identify technical, bureaucratic and infrastructural transitions that could facilitate implementation of autogenous vaccination in LMIC aquaculture against challenging socio‐economic and environmental backgrounds. The benefits of autogenous vaccination to animal welfare, transboundary biosecurity, local farmer and industry economics, and to public health, favour implementation in aquaculture as a locally enabled solution to the global problem of antimicrobial resistance.

Infectious pancreatic necrosis virus in salmonids: Molecular epidemiology and host response to infection - David Tapia; Yoanna Eissler; Felipe E. Reyes‐Lopez; Juan Kuznar; José Manuel Yáñez (Reviews in Aquaculture, 2022)
Infectious pancreatic necrosis virus (IPNV) is one of the most pervasive pathogens in aquaculture worldwide. It causes a highly contagious disease in salmonids that has a significant economic impact in almost every country where salmonid fish are farmed. For decades IPNV studies have focussed on the molecular characterisation of isolates collected from around the world and the discovery of molecular markers associated with virulence and pathogenicity. The great success of selective breeding for resistance to IPNV has caused special emphasis to be put on the immune response of salmon genetically resistant/susceptible to IPNV. In this work, we review the classification of IPNV, summarise virulence markers and add recent findings about the molecular epidemiology and worldwide distribution of the virus. We also review genetic improvements for IPNV resistance, the kinetics of the immune response to IPNV and the transcriptomic response of salmonids, made possible through the use high‐throughput technologies.

Are we actually measuring growth?—An appeal to use a more comprehensive growth index system for advancing aquaculture research - Zhen‐Yu Du; Giovanni M. Turchini (Reviews in Aquaculture, 2022)

Pinnipeds and salmon farming: Threats, conflicts and challenges to co‐existence after 50 years of industrial growth and expansion - Heide Heredia‐Azuaje; Edwin J. Niklitschek; Maritza Sepúlveda (Reviews in Aquaculture, 2022)
In this review, we summarize and discuss the main interactions affecting salmon farming and pinniped populations worldwide. Out of seven pinnipeds commonly engaged in these interactions, only one, Eumetopias jubatus , is currently listed, as ‘Near Threatened’, by the IUCN. This scenario may change as the salmon farming industry is expanding to higher latitudes and climate change is threatening many pinniped populations. Pinniped attacks cause productive and economic losses, equivalent to 1%–12% of gross production costs, due to predation, induced escapes and implementing deterrent measures. Other potential negative effects on the industry remain unassessed: lower fish growth, immunosuppression, diseases transmission, damaging infrastructure and injuring farmworkers. Main direct threats to pinnipeds include intended and unintended killing, which lack independent quantifications and have generated a growing number of ethical, economic and socio‐political concerns, as well as trade regulations affecting the industry. Physical perturbation, pollution, nutrification and/or prey subsidies related to this industry may induce behavioural, trophic and social changes, as well as breeding and/or foraging habitat loss/change in impacted areas. Despite their relevance, the magnitude and consequences of these potential impacts have been poorly evaluated and documented, precluding us from assembling accurate assessments on most interactions. Hence, we recommend focusing further research on assessing the effects of these interactions and make a call for implementing and maintaining reliable and independent records of: (i) intended and unintended killings and (ii) demography of affected populations. Implementing an ecosystem approach may be key to reduce negative impacts of salmon farming on pinnipeds and coastal ecosystems.

Research advances and future perspectives of genomics and genetic improvement in allotetraploid common carp - Lin Chen; Jian Xu; Xiaowen Sun; Peng Xu (Reviews in Aquaculture, 2022)
Aquatic species have become an integral part of human culture. As an internationally important food fish species, the common carp Cyprinus carpio accounted for over 7% of global aquaculture production in 2020. In addition to serving as a food source, common carp varieties are used as ornamental fish and valued in recreational fisheries. The continuously updated reference genome of common carp has recently served as a foundation for both basic genetic studies and evolutionary studies. With the recent emphasis on the allotetraploid signature of common carp, researchers have begun to focus on how hybridization and polyploidization affect the successful speciation and advantageous behaviour of common carp. In this review, we survey current and emerging research topics on common carp, including genomic and genetic tools, germplasm resources, genetic diversity, genetic mechanism and improvement of economic traits, as well as multiple breeding technologies employed in common carp. We also provide an overview of recent trends in genetic studies and improvements in common carp and encourage researchers to monitor the allotetraploid signature of common carp. Understanding the genetic basis of economically important traits and the mechanisms of allopolyploidization in common carp will be important for genetic improvement and germplasm innovation in agronomically important fish species, although the road ahead will be challenging for this widely domesticated allotetraploid species.

Offshore aquaculture of finfish: Big expectations at sea - Bernat Morro; Keith Davidson; Thomas P. Adams; Lynne Falconer; Max Holloway; Andrew Dale; Dmitry Aleynik; Philipp R. Thies; Faryal Khalid; Jon Hardwick; Helen Smith; Philip A. Gillibrand; et al. (Reviews in Aquaculture, 2022)
Offshore aquaculture has gained momentum in recent years, and the production of an increasing number of marine fish species is being relocated offshore. Initially, predictions of the advantages that offshore aquaculture would present over nearshore farming were made without enough science‐based evidence. Now, with more scientific knowledge, this review revisits past predictions and expectations of offshore aquaculture. We analysed and explained the oceanographic features that define offshore and nearshore sites. Using Atlantic salmon ( Salmo salar ) as a case study, we focussed on sea lice, amoebic gill disease, and the risk of harmful algal blooms, as well as the direct effects of the oceanography on the health and physiology of fish. The operational and licencing challenges and advantages of offshore aquaculture are also considered. The lack of space in increasingly saturated sheltered areas will push new farms out to offshore locations and, if appropriate steps are followed, offshore aquaculture can be successful. Firstly, the physical capabilities of the farmed fish species and infrastructure must be fully understood. Secondly, the oceanography of potential sites must be carefully studied to confirm that they are compatible with the species‐specific capabilities. And, thirdly, an economic plan considering the operational costs and licencing limitations of the site must be developed. This review will serve as a guide and a compilation of information for researchers and stakeholders.

Environmental enrichment in fish aquaculture: A review of fundamental and practical aspects - Pablo Arechavala‐Lopez; Maria J. Cabrera‐Álvarez; Caroline M. Maia; Joao L. Saraiva (Reviews in Aquaculture, 2022)
Environmental enrichment (EE) can improve the welfare of captive fish. Its objective is to provide new sensorial and motor stimulation in order to help meet their behavioural, physiological, morphological and psychological needs, whilst reducing stress and frequency of abnormal behaviours. In fish farms, rearing environments are usually designed from a human perspective and based on economic requirements, mainly for practical reasons for the farmer, with little consideration for animal welfare. Throughout aquaculture production cycles, many farming operations can be stressful for fish, and EE may not only help them cope with these stressful events but also improve their overall welfare. In recent years, increasing interest on the effects of EE in captive fish has focussed mainly on structural enrichment. However, there are many other enrichment strategies that merit attention (e.g. sensorial, occupational, social and dietary enrichment) and which may be of interest for fish farming. Here, we review in depth the existing literature on EE and its effects on the welfare of a wide range of farmed fish species, discussing the feasibility and potential applications of different EE strategies to promote fish welfare at a commercial scale. We also present a practical framework to address the design, validation and implementation of EE by the aquaculture industry, taking in consideration the technical challenges of providing enrichment for farmed fish.

A systematic meta‐analysis based review on black soldier fly ( Hermetia illucens ) as a novel protein source for salmonids - Pabodha Weththasinghe; Jon Øvrum Hansen; Liv Torunn Mydland; Margareth Øverland (Reviews in Aquaculture, 2022)
Black soldier fly ( Hermetia illucens ) has gained attention as a sustainable novel protein source in fish feed due to its high nutritional value and low environmental impacts. In the past decade, effects of the use of black soldier fly in aquafeeds have widely been studied in salmonids. A meta‐analysis was conducted to compile and systematically quantify the effect of black soldier fly in diets for salmonids on growth performance and nutrient utilization. The main meta‐analysis showed that dietary inclusion of black soldier fly did not compromise the specific growth rate, feed conversion ratio, feed intake, protein digestibility and protein efficiency ratio in salmonids. A meta‐regression was conducted to explore the possible causes of variation in growth rate, feed conversion ratio and feed intake between the studies. Fish species, protein source(s) replaced and black soldier fly inclusion level were partially responsible for the variation in growth rate between the studies. The protein source(s) replaced and black soldier fly inclusion level partially explained the variation in feed conversion ratio and feed intake respectively. The sub‐data sets sorted according to the replaced protein source(s) showed that replacing fishmeal by black soldier fly decreased growth rate and feed intake in salmonids, but replacing non‐fishmeal sources improved growth rate and feed conversion. This strengthened the importance of the type of replaced protein source(s) when evaluating nutritional values of black soldier fly for salmonids. In conclusion, the present meta‐analysis showed that black soldier fly is a promising protein source for salmonid feeds.

European lobster Homarus gammarus aquaculture: Technical developments, opportunities and requirements - James Hinchcliffe; Ann‐Lisbeth Agnalt; Carly L. Daniels; Asbj∅rn Drengstig; Ivar Lund; Jane McMinn; Adam Powell (Reviews in Aquaculture, 2022)
The European lobster ( Homarus gammarus ) has been the subject of aquaculture and related research efforts for the last 150 years, due to both the wild fishery and cultural value of the species. Since the middle of the 20th century, increasing anthropogenic pressure has led to a severe decline in wild fish and shellfish stocks, including H. gammarus , with some fisheries yet to recover. H. gammarus is amongst the most exclusive and valuable European shellfish products, and whilst management measures have been implemented to safeguard stocks, H. gammarus aquaculture is an increasingly credible approach to help to secure a sustainable lobster supply. Historically, this has been achieved by relatively small‐scale release of hatchery‐reared juveniles during stock enhancement programmes. Until recently, commercial attempts at farming have not been viable, mainly due to cost‐prohibitive technical challenges. At present, there are several promising approaches to overcome bottlenecks hampering commercialisation of lobster aquaculture. This review summarises new technical and husbandry innovations in H. gammarus culture since the start of the 21st century, including technological innovations, husbandry and expansion of the stock enhancement (release) and farming (production) sectors. Additionally, likely directions for both sectors in the coming decades are summarised, knowledge gaps identified and the societal support required to achieve further potential are discussed.

Recent developments in male fertility evaluation, sperm cryopreservation and artificial fertilisation, and their potential application to decapod crustacean aquaculture - Jon Irish Legaspi Aquino; Lisa Elliott; Chaoshu Zeng; Damien B.B.P. Paris (Reviews in Aquaculture, 2022)
To maximise productivity, a better understanding of the underlying causes of subfertility that lead to inferior offspring and high mortality is imperative. In decapod crustaceans, most research has focused on female reproductive performance, with little attention given to male fertility. Paternal genetic contribution is critical to both successful embryonic and post‐embryonic development. Assessment of sperm quality can be a direct method to determine male subfertility in decapods. Sperm quality parameters such as sperm concentration and morphology have traditionally been used to determine male reproductive performance, but these procedures are time‐consuming and can only assess a limited number of sperm cells and males. Alternative diagnostic biomarkers used widely in humans and other mammals could be adapted to decapod crustaceans and may be more indicative of sperm fertilisation competence and male reproductive performance. These predictive biomarkers use fluorescent cellular dyes and high‐throughput flow cytometry or computer‐assisted sperm microscopic analysis to evaluate sperm viability, mitochondrial function, acrosome reaction and DNA fragmentation. This review examines current and advanced biomarkers to evaluate sperm quality and further explores state‐of‐the‐art procedures of sperm cryopreservation (conventional vs. vitrification techniques) and artificial fertilisation in decapod crustaceans. Sperm freezing coupled with artificial fertilisation in decapods permits the long‐term storage, controlled timing and selection of individuals for reproduction. Collectively, these tools can be applied to commercial broodstock management to improve productivity and accelerate selective breeding in the crustacean aquaculture industry.

How should we monitor welfare in the ornamental fish trade? - Megan Jones; Mhairi E. Alexander; Donna Snellgrove; Peter Smith; Sam Bramhall; Peter Carey; Fiona L. Henriquez; Iain McLellan; Katherine A. Sloman (Reviews in Aquaculture, 2022)
The global ornamental fish trade is a multibillion‐dollar industry, with legal trade estimated to be worth between $15 and 20 billion per annum . Although there is existing legislation concerning the improvement of fish welfare in aquaculture and research, there is little legislation surrounding the welfare of pet fish. The different phases of the ornamental fish trade, including curation, transportation, time spent at wholesalers/retailers and time spent in domestic/public aquaria, represent different welfare concerns. Within the animal welfare field there is increasing interest in improving welfare through the creation of operational welfare indicators (OWIs), where individual indicators are aggregated to assess animal welfare. OWIs can be morphological, behavioural, physiological, metabolic or abiotic in nature, with behaviour often considered as the foremost non‐invasive method of elucidating welfare in fish. Currently, while OWIs exist for food fish species, there are no OWIs for use within the ornamental fish trade. This review looks briefly at the stressors experienced by fish within the ornamental trade, and then used a systematic approach (keywords behavio* AND fish* AND welfare) to identify relevant publications investigating existing behavioural measures of welfare used for ornamental fish species. Finally, this review considers the potential development of OWIs for the ornamental trade.

Governing aquaculture commons - Stefan Partelow; Achim Schlüter; Aisa O. Manlosa; Ben Nagel; Adiska Octa Paramita (Reviews in Aquaculture, 2022)
Knowledge of the shared resources—or commons—that aquaculture systems rely on, and the appropriate rule and norm systems to govern them—or institutions—is far behind other natural resource use sectors. In this article, we provide a conceptual framework for identifying the social and environmental commons creating collective action problems for aquaculture governance. Collective action problems, or social dilemmas, create problems for governing shared resources because the typical strategies for individual use (maximisation; free riding) are often divergent from broader group interests (e.g. fair contributions; sustainable use). This framework helps identify two types of collective action problems in aquaculture: first‐order (direct use and provision of commons) and second‐order (provision, maintenance and adaptation of institutions to govern commons). First‐order aquaculture commons with governance challenges include water quality, water quantity, physical space, inputs, genetic diversity, mitigating infectious disease, earth and climate stability, infrastructure, knowledge and money. Second‐order institutions govern the use of first‐order commons. These include rule and norm systems that structure property rights and markets, aiming to better align individual behaviour and collective interests (e.g. sustainability goals) through governance. However, which combination of institutions will fit best is likely to be unique to context, where aquaculture has important differences from capture fisheries and agriculture. We provide four case examples applying our conceptual framework to identify existing aquaculture commons, institutions and governance challenges in Peru (mariculture), the Philippines (earthen ponds), Nepal (raceways) and Denmark (recirculation).

Socioecological factors related to aquaculture introductions and production of Pacific oysters ( Crassostrea gigas ) worldwide - María Fernanda Martínez‐García; Jennifer L. Ruesink; José Manuel Grijalva‐Chon; César Lodeiros; José Alfredo Arreola‐Lizárraga; Enrique de la Re‐Vega; Alejandro Varela‐Romero; Jorge Chávez‐Villalba (Reviews in Aquaculture, 2022)
Pacific oysters ( Crassostrea gigas ) have been introduced worldwide for aquaculture, which can benefit food sovereignty and economic development; however, established non‐native populations may present risks for local organisms and habitats. We reviewed the documented introductions of C. gigas by country to evaluate factors related to introduction, establishment and production, and to determine impacts of feral populations. To date, C. gigas has been introduced in 64 countries and 10 territories, has been established in 32 and contributes to cupped oyster production in 36 (additionally, three native range countries). Oysters were more likely to be introduced and to establish in higher‐latitude countries, but the economic factor of per capita Gross Domestic Product per capita (GDPpc) served as a stronger explanatory variable than latitude for introduction. Earlier introduction and the use for extended periods in aquaculture, not just in trials, further increased establishment. Commercial production increased with coastline length and when established populations were present, but in contrast to establishment, declined at higher latitude. Effects of feral populations have been studied in 11 countries, spanning a range from negative to facilitative as expected for an ecosystem engineer, while reaching levels of concern warranting removal from coastlines in the UK, Norway, Sweden Australia and South Africa. The use of GDPpc in analyses revealed a widespread inequity in terms of low investment in Pacific oyster aquaculture in poorer countries, while richer countries were able to invest not only in aquaculture but also in studies of environmental impacts of feral oysters.

Diverse state‐level marine aquaculture policy in the United States: Opportunities and barriers for industry development - Sarah E. Lester; Rebecca R. Gentry; Hayley R. Lemoine; Halley E. Froehlich; Luke D. Gardner; Mae Rennick; Elizabeth O. Ruff; Kimberly D. Thompson (Reviews in Aquaculture, 2022)
Marine aquaculture (mariculture) plays a relatively small role in the United States’ domestic seafood production, despite considerable scope for industry development and high volumes of imported farmed seafood resulting in a significant trade deficit. Currently, most mariculture in the United States occurs in nearshore waters or land‐based tanks and is regulated and guided using state‐level policy, with a relative absence of national coordinating mechanisms to link the patchwork of state policies. There is no comprehensive evaluation showing how different state policies may be enabling or impeding mariculture development. In response, we provide the first systematic overview of state‐level mariculture policy for the 23 coastal marine states in the United States. We compiled information for 16 aquaculture and mariculture policy attributes, including legislation, regulations and management characteristics, particularly those that could enable mariculture development. We found considerable heterogeneity in how states govern and regulate mariculture. As examples, 48% of states have an aquaculture development act, 35% have spatial zoning specifically for mariculture and only 26% have a government‐provided mariculture best management practices document. We examined the relationship between enabling policies and metrics of mariculture output (e.g. production value, number of farms), and while the effect of enabling policy is often equivocal, certain features stand out as important (e.g. government‐provided best management practices). Overall, this policy synthesis suggests approaches that may be influential in enabling mariculture development, which could inform new state‐level policies, an effective overarching federal policy in the United States, or policies in other countries seeking to support an expanded mariculture industry.

On the silver jubilee of crustacean antimicrobial peptides - Gabriel Machado Matos; Rafael Diego Rosa (Reviews in Aquaculture, 2022)
Antimicrobial peptides (AMPs) are widely distributed effector molecules that provide a first line of defence for organisms that lack adaptive immunity, such as crustaceans. They also represent bioactive molecules with great potential as therapeutic agents in aquaculture and biomedicine. Over the last years, an intensive research effort has been devoted to the identification and characterisation of antimicrobials in crustaceans resulting in the recognition of twelve gene‐encoded AMP families to date. In addition to classical linear and multi‐domain AMPs, crustaceans also rely on the production of unconventional ones, such as lysozymes and AMPs encrypted in large proteins carrying nonimmune functions. Besides their molecular and functional diversity, crustaceans have a particular AMP repertoire usually composed of diverse multigene families of taxonomically restricted peptides/polypeptides. In fact, only a few families of AMPs are shared between crustaceans and their close arthropod relatives. This review celebrates the silver jubilee of the discovery of the first crustacean AMPs and presents an updated and comprehensive overview in terms of structure, diversity and biological properties, emphasising their role in immune responses and in host‐microbe interactions. We also discuss the main progress achieved so far and major challenges remaining.

FLOCponics: The integration of biofloc technology with plant production - Sara M Pinho; Jéssica P de Lima; Luiz H David; Maurício G C Emerenciano; Simon Goddek; Marc C J Verdegem; Karel J Keesman; Maria Célia Portella (Reviews in Aquaculture, 2022)
FLOCponics is an alternative type of aquaponics that integrates biofloc technology (BFT) with soilless plant production. The aims of this paper are to present a detailed overview of the FLOCponics system's designs and performance, discuss their sustainability, highlight the current challenges, and give directions for future research. Data sources include papers containing the keywords bioflocs and hydroponics, aquaponics and/or plant production. In view of the small number of publications and the lack of standardization in experimental design and system setup, it was concluded that FLOCponics is still in its initial research stage. With respect to the animal and plant yields in FLOCponics, inconsistent results were found. Some investigations presented better or similar yield results in this system compared to traditional cultures, while others found the opposite. One of the key challenges of using FLOCponics is the effective control of solids. Refining the system's design was the main recommended improvement. Moreover, this paper highlights that the commercial application of FLOCponics will require extensive research that clarifies its technical and economic aspects, originating from experimental or pilot‐scale setups with characteristics similar to commercial production. This review provides and discusses information that can be useful for the effective development of FLOCponics, guiding further research to make FLOCponics commercially feasible and thus contributing to sustainable aquaculture production.

Interactions and associated resistance development mechanisms between microplastics, antibiotics and heavy metals in the aquaculture environment - Zhen Li; Muhammad Junaid; Guanglong Chen; Jun Wang (Reviews in Aquaculture, 2022)
Microplastics (MPs), antibiotics and heavy metals unavoidably contaminate the aquaculture environment, with serious ecological and human health consequences. Antibiotic‐resistance genes (ARGs) and metal resistance genes (MRGs) are induced in microorganisms in the environment as a defence mechanism against antibiotics and heavy metals respectively. Furthermore, heavy metals in the aquaculture environment will cause bacteria to employ antibiotic resistance through co‐selection (co‐resistance or cross‐resistance) and other potential mechanisms. MPs may also act as potential carriers of multidrug resistance in aquaculture environments because they are hotspots for the enrichment and transmission of antibiotic resistance. Multidrug‐resistant (MDR) microorganisms in the aquaculture environment may infiltrate aquatic organisms via the food chain (eg MDR‐microorganisms→myctophids→ tuna/ squid/ whales/ seabirds/ seals), and after long‐term enrichment, they may gain access to the human body, posing a major risk to aquaculture and human health. As a result, this review article summarises contamination of MPs, heavy metal and antibiotics in global aquaculture settings; discusses the generation of ARGs, MRGs and common selection mechanisms for resistance development and emphasises the role of MPs as hot spots for antibiotic‐resistance selective enrichment, as well as potential carriers of multi‐drug‐resistant genes (MDRGs), in the aquaculture environment, posing an increasing threat to aquaculture and even human health.

The farming and husbandry of Colossoma macropomum : From Amazonian waters to sustainable production - Alexandre Wagner Silva Hilsdorf; Eric Hallerman; Gustavo Moraes Ramos Valladão; Micheli Zaminhan‐Hassemer; Diogo Teruo Hashimoto; Jony Koji Dairiki; Leonardo Susumu Takahashi; Francielly Corrêa Albergaria; Maria Emília de Sousa Gomes; Rossana Luiza Leite Venturieri; Renata Guimarães Moreira; José Eurico Possebon Cyrino (Reviews in Aquaculture, 2022)
Within the rich diversity of South American freshwater fish, Colossoma macropomum (Characiformes: Serrasalmidae), known as tambaqui, cachama or blackfin pacu, can reach 30 kg, is a traditional product in regional fish markets and has drawn the attention of fish farmers since the 1930s. Considerable progress achieved in different fields of aquaculture science has contributed to the growth of tambaqui production. Tambaqui has proven suitable for both monoculture and polyculture systems, and for both extensive and intensive production systems aimed at achieving sustainable, higher productivity with minimal environmental impact. Studies of the reproductive anatomy and physiology of the species proved fundamental to development of techniques to boost commercial production, contributing to development of protocols for hormonally induced spawning and artificial propagation in the 1970s. Newly hatched larvae must be fed with live foods until they can be weaned to artificial feeds at about 100 mg weight. Despite its importance for aquaculture, only a few studies have reported components of quantitative genetic variance and parameters for weight at age, morphometric traits and disease resistance. Genomic tools currently available can be applied to detect variation relevant to performance and to accelerate the process of genetic improvement. While the species’ feeding habit allows the use of diets containing 75%–85% plant protein, much more work needs to be done to optimize aquafeeds. Refinement of tambaqui production methods has the potential to significantly boost South American aquaculture. We recommend research on diets, genetic improvement and system optimization to spur further productivity and achieve sustainable tambaqui culture.

The role of currently used medicinal plants in aquaculture and their action mechanisms: A review - Dawit Adisu Tadese; Changyou Song; Cunxin Sun; Bo Liu; Bo Liu; Qunlan Zhou; Pao Xu; Xianping Ge; Mingyang Liu; Xiaodi Xu; Metekia Tamiru; Zhigang Zhou; et al. (Reviews in Aquaculture, 2022)
Global aquaculture development increased rapidly in recent years, and the sector has become one of the fastest‐growing industries in the animal‐derived food production system. However, disease outbreak remains a major challenge that hinders sustainable production through an advanced level of intensification. Recently, antibiotics applied have been restricted globally against aquatic disease outbreaks due to their apparent accumulation in the tissues, which imposes on the development of resistant bacteria. Naturally available medicinal plants were tested to combat some pathogens affecting humans and animals, as they contain a wide range of active substances that can induce biological functions. Currently, medicinal plants are being tested in aquaculture as a safe and eco‐friendly substance to modulate immune status, enhance growth performance and prevent fish disease. Moreover, different parts (e.g. leaf, flower and rhizome) and forms (e.g. crude, extract and active ingredient) of plants are used to modulate specific biological functions (e.g. growth promoter, anti‐stress, immunostimulants, appetite stimulation, antibacteria, anti‐parasite and anti‐virus). Medicinal plants are also used to defend the aquaculture animal from external stressors, such as poor water quality, high environmental temperature and overcrowding. This paper aims to provide information on the role of currently used medicinal plants on aquaculture animals and their action mechanisms. In conclusion, the current review suggested that the utilisation of medicinal plants remained untapped in uncovering the biological activities of active substances against a variety of diseases across diverse species of aquaculture animals.

Role of hypoxia in the behaviour, physiology, immunity and response mechanisms of crustaceans: A review - Cheng Zheng; Qianqian Zhao; Erchao Li; Daxian Zhao; Shengming Sun (Reviews in Aquaculture, 2022)
Crustaceans are often exposed to hypoxic stress in intensive aquaculture systems. Such stress leads to physiological, behavioural and biochemical changes, which can cause various metabolic disorders or even death. Crustacean response mechanisms to hypoxia stress are known to be complex, with their regulation involving multiple genes. In this review, after briefly exploring some known causes of hypoxic stress in aquaculture systems, we discuss the physiological adaptation strategies used by crustaceans in response to hypoxia and summarise recent information regarding the effects of hypoxia on the behaviour, survival, antioxidant ability, metabolic processes and innate immunity of crustaceans. In addition, we give particular emphasis to the known molecular mechanisms underlying hypoxia related to the hypoxia‐inducible factor 1 (HIF‐1) signalling pathway, the adenosine 5′‐monophosphate‐activated protein kinase signalling (AMPK) pathway, and apoptosis. Practically, it is clear that multiple measures need to be taken to prevent and regulate the adverse effects of hypoxic stress in intensive aquaculture systems, including development of hypoxia‐resistant breeds and nutritional regulation techniques. Overall, this review provides a theoretical basis for understanding the molecular mechanisms underlying hypoxic stress in crustaceans, while making conceptual connections with data from related study areas in other species.

Metabolomics in salmonid aquaculture research: Applications and future perspectives - Ronald Lulijwa; Andrea C. Alfaro; Tim Young (Reviews in Aquaculture, 2022)
Salmonids are the third major farmed finfish species after carps and tilapines, and thus contribute to global food fish production. However, as the aquaculture industry continues to grow, several challenges have emerged. Left unchecked, current problems will hinder aquaculture development. Metabolomics is one of the powerful biotechnological tools that will contribute to solving some of the pressing problems. This review aims to summarise findings and identify gaps from studies that used metabolomics in farmed salmon research. We extracted methodological information for comparison, highlighted analytical platform usages and identified most studied salmonids and sample types. We reviewed key articles to highlight the latest research themes. From the identified research gaps, future perspectives regarding potential use of metabolomics to solve issues in ecotoxicology, thermotolerance, nutrition, post‐harvest quality, health and disease, and husbandry practices are provided. The survey also highlighted improvements in execution of metabolomics protocols in aquaculture.

The importance of vitamin E for farmed fish—A review - Abdel‐Fattah M. El‐Sayed; Marisol Izquierdo (Reviews in Aquaculture, 2022)
Vitamin E (VE) is composed of a group of fat‐soluble molecules, from which the most active homologous is α‐tocopherol. VE is a structural component of cell membranes with a potent chain‐breaking antioxidant action, which plays a main role in several biological processes. In cultured fish, VE can prevent peroxidation of cellular and subcellular membrane phospholipids and also red blood cells, leading to maintaining the structural and functional integrity of animal cells. VE performs several other biological and metabolic functions, including improvement of the immune response, enhancing growth performance and feed efficiency, preventing muscle degeneration, reducing the risk of atherosclerosis, improving reproductive efficiency and larval performance, meat quality and shelf life of seafood. Besides, VE interacts with other micronutrients, especially vitamin C and selenium. Fish feed and fish flesh generally contain high concentrations of lipids, especially polyunsaturated fatty acids, which renders these lipids more susceptible to lipid peroxidation. Supplemental VE may, therefore, become necessary to prevent this peroxidation. However, the VE requirement of farmed aquatic animals varies significantly, depending on dietary contents of VC, selenium and lipid (unsaturated fatty acids). This review summarizes the current knowledge on the physiological functions of VE in farmed fish and shrimp, and the effects of supplemental VE on fish performance, reproduction, health and product quality. The future considerations of VE requirements of farmed fish in light of the predicted climate change have also been discussed, especially with regard to feed input supplies (fish meal and fish oil vs. plant proteins and oils) and weather temperature.

Internet of Things (IoT)‐based aquaculture: An overview of IoT application on water quality monitoring - Dipika Roy Prapti; Abdul Rashid Mohamed Shariff; Hasfalina Che Man; Norulhuda Mohamed Ramli; Thinagaran Perumal; Mohamed Shariff (Reviews in Aquaculture, 2022)
Aquaculture based on the Internet of Things (IoT) is a growing field of interest in the fishing industry. The IoT technology is advancing the agriculture 4.0 era, and yet, Aquaculture 4.0 is a lagging field in many countries. This article presents results obtained so far from ongoing research of published work highlighting water quality monitoring in fishponds. This analysis was performed extensively from May to December 2020 by meticulously selecting a total of 30 internationally published research papers. This review is divided into five categories: (1) recent research (2011–2020), (2) aquaculture environments, (3) research approaches, (4) most common water quality parameters and (5) forms of the solution provided. Most of the published research concentrated on inland aquaculture (81%), while research articles on marine aquaculture species accounted for 19% of papers reviewed so far. The framework and architecture approach (48%) was the most widely practised research approach in IoT‐based aquaculture for water quality monitoring. There is a need for long‐term experimental research to identify the challenges and suggest appropriate solutions. With regards to water quality parameters, temperature (20%), dissolved oxygen (18%) and pH (17%) are the topmost prioritised water quality parameters considered in the IoT‐based aquaculture. Finally, real‐time monitoring (50%) is offered generally as a form of a solution while autonomous (3%) monitoring can be a unique solution. The findings from this study are expected to support the aquaculture industry, researchers, practitioners and decision‐makers in the long run.

Double‐edged sword role of shrimp miRNA explains an evolutionary language between shrimp‐pathogen interactions that unties the knot of shrimp infection - Hari Deva Muthu B; Ajay Guru; Gokul Sudhakaran; Raghul Murugan; Aziz Arshad; Jesu Arockiaraj (Reviews in Aquaculture, 2022)
Shrimp production, using a small‐scale enclosed pond system, is a rapidly growing aquaculture sector, which is valued around USD 18.30 billion in 2020. Intensified shrimp culture leads to the outbreak of transmissible diseases to eventually cause a huge loss in the production process and thus the economy. Studies on microRNA (miRNA) reveal that miRNA has an influential role in the host‐pathogen interaction during an infection. Recently, shrimp miRNA has been shown to help pathogen‐like viruses for their replication and infection. Several shrimp miRNAs were reported to be involved in enhancing host immunity against viral infection, especially white spot syndrome virus (WSSV) infection and Vibrio infection caused by bacterial species, whereas some shrimp miRNAs were reported to be hijacked by WSSV and to enhance the viral replication and establish the infection in shrimp. This gives an insight into the double‐edged sword role played by shrimp miRNA during host‐pathogen interaction. In future, this role could be employed against the virus to strengthen the shrimp culture. In this review, we discuss the role of shrimp miRNA and their mechanism(s) associated with the establishment of host‐pathogen interaction during infection, which will reveal the complexity associated with shrimp infection.

Immune functions of phagocytic blood cells in teleost - Wentao Zhu; Jianguo Su (Reviews in Aquaculture, 2022)
Phagocytosis is a fundamental immune function against foreign microorganisms and abnormal cells, and it is also a bridge between innate and adaptive immunity. Blood as the direct living environment of various immune cells is a crucial site for phagocytosis. In this review, we firstly summarized the morphological structure and cytochemical characteristics of teleost peripheral blood cells, divided them into erythrocytes, leucocytes and thrombocytes, and then systematically elaborated the immune functions of phagocytic blood cells including professional and non‐professional phagocytes. The professional phagocytes consist of monocytes/macrophages and neutrophils. Monocytes/macrophages activate phagocytosis to ingest pathogens, and destroy them through respiratory burst and nitric oxide response to generate antigens, and then antigens are presented to adaptive immune cells. Neutrophils are recruited to inflammatory sites and exert phagocytosis, which is accompanied by degranulation and the production of neutrophil extracellular traps to kill pathogens. Non‐professional phagocytes including thrombocytes, B cells and erythrocytes are indispensable to exercise the phagocytosis, in addition to their main functions in the immune system. Thrombocytes participate in innate immunity and adaptive immunity. B cells carry out antigen presentation and immunoglobulin secretion in adaptive immunity. Erythrocytes perform immune regulation and infection resistance. In general, professional phagocytes play a primary role in phagocytosis and pathogen treatment, whereas non‐professional phagocytes play auxiliary role in phagocytosis and perform their unique immune functions. The functions of these two types of phagocytes jointly constitute the basis of the immune system. This review provides insights into the overall roles of phagocytic blood cells in the teleost immune system.

Issue Information (Reviews in Aquaculture, 2022)

A comprehensive review of oyster peptides: Preparation, characterisation and bioactivities - Lili Hao; Xincen Wang; Yunrui Cao; Jie Xu; Changhu Xue (Reviews in Aquaculture, 2022)
Oysters are a healthy and excellent source of lean protein (content up to 45%–57%). In addition, polypeptides extracted from hydrolysis of oyster protein by enzymatic hydrolysis or fermentation have diverse bioactivities, such as antioxidant, antimicrobial, antihypertensive, promoting sexual reproduction, anti‐inflammatory and anticancer. However, there are still great challenges in the preparation and characterisation of oyster polypeptides. Besides, the bioactivities and the corresponding underlying mechanisms of oyster peptides (OPs) have not yet been fully described. In order to obtain more specific peptides with potential bioactivities, optimisation of conditions employed during hydrolysis of oyster protein is therefore necessary, as well as the identification of the amino acid sequence and secondary structure of OPs. This review discusses latest research progress in preparation (including production, isolation and purification) and characterisation of OPs, with emphasis on their multiple bioactivities. Mechanisms underlying such bioactivities have also been presented. Comprehensive information about OPs could pave the way towards a functional development and more efficient utilisation of oysters. Collectively, there is growing evidence that OPs have potential health benefits. More research efforts are needed to determine their potential use in many contexts and ultimately develop more efficient and safer OP‐based products.

How probiotics impact on immunological parameters in rainbow trout ( Oncorhynchus mykiss )? A systematic review and meta‐analysis - Ruhollah Rahimi; Seyedeh Atefeh Mirahmadi; Saeed Hajirezaee; Aziz A. Fallah (Reviews in Aquaculture, 2022)
Probiotics are microbial cells with multifunctional properties including immunostimulatory function in their host. Today, probiotics are widely used for controlling diseases in aquaculture, especially for rainbow trout, Oncorhynchus mykiss , as the most important commercial cold‐water fish in the world. So far, many studies have been conducted on the effect of probiotics on the immune system of rainbow trout, but due to different experimental conditions, these results are different and sometimes inconsistent. Therefore, the aim of the present study was to perform a systematic review and meta‐analysis to eliminate inconsistencies and to clarify the results related to some immune parameters in rainbow trout. This study is the first meta‐analysis study of probiotic‐induced effects on the immune system of rainbow trout. In order to perform meta‐analysis, four Internet databases, PubMed, Scopus, ISI Web of Science and Google Scholar were systematically searched until 27/03/2020 and after receiving related articles, effect sizes related to 10 outcomes including serum and plasma lysozyme activity, ACH50 activity, Ig activity, serum complement activity, phagocytosis activity, serum total protein activity and respiratory burst activity were evaluated by SMD and Hedges' g statistic and 95% CI was calculated from a random effects model. The SYRCL’S risk of bias tool for animal study was also used to assess the quality of the studies. Meta‐analysis was performed for 36 studies by 499 experiments. The effect of probiotics on immunity components was as follows: serum lysozyme activity ( p p > 0.05), Serum ACH50 activity ( p p p p p p p p > 0.05). In conclusion, the results of the present study showed that, except plasma lysozyme activity and burst activity, probiotics could enhance immune system of rainbow trout.

Addressing the welfare needs of farmed lumpfish: Knowledge gaps, challenges and solutions - Carlos Garcia de Leaniz; Carolina Gutierrez Rabadan; Sara I. Barrento; Rebecca Stringwell; Paul N. Howes; Ben A. Whittaker; Jessica F. Minett; Robert G. Smith; Craig L. Pooley; Ben J. Overland; Leigh Biddiscombe; Richard Lloyd; et al. (Reviews in Aquaculture, 2022)
Lumpfish ( Cyclopterus lumpus L.) are increasingly being used as cleaner fish to control parasitic sea lice, one of the most important threats to salmon farming. However, lumpfish cannot survive feeding solely on sea lice, and their mortality in salmon net‐pens can be high, which has welfare, ethical and economic implications. The industry is under increasing pressure to improve the welfare of lumpfish, but little guidance exists on how this can be achieved. We undertook a knowledge gap and prioritisation exercise using a Delphi approach with participants from the fish farming sector, animal welfare, academia and regulators to assess consensus on the main challenges and potential solutions for improving lumpfish welfare. Consensus among participants on the utility of 5 behavioural and 12 physical welfare indicators was high (87–89%), reliable (Cronbach's alpha = 0.79, 95CI = 0.69–0.92) and independent of participant background. Participants highlighted fin erosion and body damage as the most useful and practical operational welfare indicators, and blood parameters and behavioural indicators as the least practical. Species profiling revealed profound differences between Atlantic salmon and lumpfish in relation to behaviour, habitat preferences, nutritional needs and response to stress, suggesting that applying a common set of welfare standards to both species cohabiting in salmon net‐pens may not work well for lumpfish. Our study offers 16 practical solutions for improving the welfare of lumpfish and illustrates the merits of the Delphi approach for achieving consensus among stakeholders on welfare needs, targeting research where is most needed and generating workable solutions.

An overview of jellyfish aquaculture: for food, feed, pharma and fun - Inês Matos Duarte; Sónia Cotrim Marques; Sérgio Miguel Leandro; Ricardo Calado (Reviews in Aquaculture, 2022)
Interest on jellyfish research has significantly increased over the last two decades, mostly driven by the potential benefits of their high‐end uses. Recent efforts have been put forward towards the commercial use of scyphozoan jellyfish, although the pipeline leading to their full exploitation is still at an early stage of development. Indeed, further research and several technical advances are still required to expand the use of these bioresources to a larger and more sustainable scale. Here, we describe the state of the art of culture systems already available to farm these organisms throughout the different stages of their life cycle and provide an overview of the potential applications of jellyfish aquaculture for food, feed, as source of bioactive compounds for pharmaceutical and other biotechnological applications, as well as to supply the marine aquarium trade. Overall, this work aims to raise awareness on the relevance that jellyfish will likely play on the development of sustainable blue bioeconomy frameworks fostering a sustainable valorisation of marine living resources.

Review of shell waste reutilization to promote sustainable shellfish aquaculture - Junxiong Zhan; Jinshan Lu; Di Wang (Reviews in Aquaculture, 2022)
Shellfish aquaculture has developed rapidly, and the annual production of shell waste by‐products exceeds 10 million tons. The reutilization of shell waste is a severe problem in terms of environmental protection and the development of the circular economy. Due to its limited economic value, shell waste has generally been discarded or sent to landfill without any further processing and reutilization, thereby wasting resources and severely degrading the coastal ecosystem. This review summarizes recent research into the reutilization of shell waste, including applications in the fields of agriculture, construction, environmental protection, chemical production, food additives and biomaterials. Problems and strategies related to the reutilization of shell waste are analysed in order to provide technical support for the large‐scale and high value‐added utilization of shell waste.

PORTUGUESE‐BRAZILIAN ABSTRACTS (Reviews in Aquaculture, 2022)

The omega‐3 sparing effect of saturated fatty acids: A reason to reconsider common knowledge of fish oil replacement - Artur N. Rombenso; Giovanni M. Turchini; Jesse T. Trushenski (Reviews in Aquaculture, 2022)

Ice‐Ice disease: An environmentally and microbiologically driven syndrome in tropical seaweed aquaculture - Georgia M. Ward; Cicilia S. B. Kambey; Joseph P. Faisan; Pui‐Ling Tan; Caroline C. Daumich; Ivy Matoju; Grant D. Stentiford; David Bass; Phaik‐Eem Lim; Juliet Brodie; Sze‐Wan Poong (Reviews in Aquaculture, 2022)
Seaweeds account for nearly 30% of global aquaculture production by volume, and their cultivation provides important opportunities for employment and wealth generation, particularly in rural coastal communities. Eucheumatoids ( Kappaphycus and Eucheuma spp.) are tropical red algae commercially cultivated as raw material for production of carrageenans, particularly in South‐East Asia and the Western Indian Ocean region. Diseases and pests are major limiting factors in eucheumatoid production, particularly a condition known as ‘ice‐ice’ disease (IID). IID is characterized by bleaching of the thallus followed by the disintegration of affected tissues, leading to a loss of biomass and reduced carrageenan yield. IID has been associated with unfavourable changes in environmental conditions, particularly an increase in sea water temperature and a decrease in salinity, and infection by opportunistic or pathogenic bacteria. However, given that no single or combined causal agents have been definitely identified, IID may be considered a complex pathobiotic syndrome in which multiple factors contribute to the development of disease signs. Here, we review current knowledge of the abiotic and biotic factors associated with the development of IID, and the strategies employed to mitigate economic losses resulting from disease outbreaks. We discuss syndromic diseases in other marine holobionts, particularly other red algae and corals, in relation to their similarity to IID, and suggest the application of comprehensive and complementary methodologies, including high‐throughput sequencing and high‐quality microscopy, for enhancing our understanding of the pathological and microbiological processes associated with IID signs.

CHINESE ABSTRACTS (Reviews in Aquaculture, 2022)

Treated municipal wastewater as a water source for sustainable aquaculture: A review - Inbal Zaibel; Shai Arnon; Dina Zilberg (Reviews in Aquaculture, 2022)
Aquaculture has been the fastest‐growing food production sector during the last decades. The supply–demand gap for fish is constantly widening, and declining freshwater availability is becoming a major limiting factor for production. Exploring alternative water resources, such as treated wastewater (TWW), has become a growing strategy for coping with the increasing water demand in agriculture. Reuse of wastewater or TWW for agriculture and aquaculture has been practiced around the world for centuries. However, the extent of the practice and the scientific attention paid to TWW reuse for aquaculture are negligible compared to those for agricultural irrigation. The objectives of this review are to present the existing literature on treated‐wastewater‐fed aquaculture, to evaluate the prospective reuse of TWW for aquaculture and its economic appraisal, and to identify the scientific and legislative gaps and challenges towards implementation. Most of the published studies on fish culture in TWW suggest that it is feasible in terms of fish survival and growth. Research also shows that fish are safe for human consumption in terms of microbiological contamination and the bioaccumulation of heavy metals and certain organic‐micropollutants, with levels found to be in accordance with international standards for human consumption. Moreover, reuse of TWW as an alternative water source for aquaculture holds economic and environmental advantages. It appears that the sociocultural perception is a major barrier, which can be overcome by a combination of further research, legislation and public relations, which can support the implementation of TWW reuse for aquaculture.

Emerging indicators of fish welfare in aquaculture - Michelle Orietta Barreto; Sonia Rey Planellas; Yifei Yang; Clive Phillips; Kris Descovich (Reviews in Aquaculture, 2022)
As aquaculture continues to grow and intensify, there is an increasing public concern over the welfare of farmed fish. Stress and production‐related pathologies and repressed growth are examples of the challenges facing aquaculture, and their impacts could be minimised by effective identification of the early signs of impaired welfare. Many welfare monitoring methods have been recommended; however, continuous and reliable welfare monitoring in aquaculture is not yet widespread and commonplace. The aim of this scoping review was to present an overview of the most recent developments in fish welfare assessments with a specific focus on practical translation to the aquaculture industry. A keyword‐based search was undertaken to identify peer‐reviewed papers published between 2014 and 2020 in which a novel method with the potential to be used for the assessment of fish welfare in aquaculture was introduced. The results were sorted into two categories: non‐invasive and invasive methods. All methods were assessed for their advantages and disadvantages, potential applicability to aquaculture. Invasive methods were also ranked on their degree of impact. It is concluded that increased interest into fish welfare, in combination with more intelligent modern technology, has resulted in the development of newer and more refined alternatives to traditional methods of welfare assessment such as behaviour monitoring by 2D cameras and plasma cortisol evaluation. Although, in many cases, more research is needed before these methods are suitable for widespread industry use, studies that focus on increasing the precision, automation and practical applicability of these methods are a promising avenue for future research.

Genome editing and its applications in genetic improvement in aquaculture - Zituo Yang; Yepin Yu; Yi Xuan Tay; Gen Hua Yue (Reviews in Aquaculture, 2022)
In the aquaculture industry, selective breeding has played an important role in increasing aquaculture production significantly. To meet the global growing demand for high quality proteins, it is essential to apply novel technologies to accelerate breeding to facilitate the increase in aquaculture production. Gene and genome editing technologies, including ZFNs, TALLENS and Crispr/Cas9, are promising tools to speed up genetic improvement. Among all the genome editing approaches, the CRISPR/Cas9 system is faster, cheaper and precise in editing genes/genomes. Therefore, the application of CRISPR/Cas9 technology in the editing of genomes in aquaculture species is emerging rapidly. It has been applied to precisely edit genes to identify gene functions and generate the preferred traits in over 20 aquaculture species. This review summarises the genome editing technologies and their applications in the rapid improvement of economic traits in the aquaculture industry. Challenges and future directions of genome editing are also discussed.

Environmental consequences of using insect meal as an ingredient in aquafeeds: A systematic view - Hung Quang Tran; Hien Van Doan; Vlastimil Stejskal (Reviews in Aquaculture, 2022)
We retrieved data from various studies to investigate the consequences of insect meal production and insect meal‐based diets with respect to their environmental impact, including global warming potential, energy use, land use, water use, acidification, eutrophication as well as to economic fish‐in fish‐out ratio and solid waste output production. Analysis indicated that insect meals’ production exerted positive effects on land use but was associated with greater energy use and a larger carbon footprint compared to conventional protein sources. Substitution of silkworm meal ( Bombyx mori ) meals for fishmeal in aquatic animal diets significantly reduced solid phosphorus waste compared to insect‐free diets. In contrast, the inclusion of black soldier fly ( Hermetia illucens ), housefly ( Musca domestica ), mealworm ( Tenebrio molitor ) and grasshopper ( Zonocerus variegatus ) has led, in comparison to insect‐free diet, to greater solid nitrogen waste. Reducing the proportion of fishmeal and, to a lesser extent fish oil, by various insect meals in aquatic diet formulations significantly reduces economic fish‐in fish‐out, indicating less marine forage fish required per unit fish yield. The simulated data showed environmental benefit associated with land use of insect‐containing aquafeeds compared to insect meal‐free feeds, especially insect species of M . domestica and T . molitor . In all, this study suggested a trade‐off of using insect meal as an aquafeed ingredient regarding environmental consequence. Since insect meal has excellent potential to supply protein for aquafeeds in the coming years, improvement in insect meal production systems and nutritional composition will be essential to make insect meal a sustainable aquafeed ingredient.

Reviews and industry: A love‐hate relationship - Umberto Luzzana; Giovanni M. Turchini (Reviews in Aquaculture, 2022)

SPANISH ABSTRACTS (Reviews in Aquaculture, 2022)

An appraisal of the variable response of microalgal lipids to culture salinity - José‐Pedro Cañavate; Catalina Fernández‐Díaz (Reviews in Aquaculture, 2022)
Salinity is a basic factor in microalgal aquaculture production that is easier to manage than other external factors. Optimized use of salinity is key to achieving widespread microalgal production that is more sustainable by avoiding freshwater inputs. Since salinity influences the content of many high‐value lipid compounds in microalgae, assessing how the diverse plasticity of salt metabolism in numerous marine and freshwater microalgae is reflected in their broad lipid repertoire is an important issue that has yet to be addressed. Current studies indicate that a low phylogenetic diversity has been covered, as well as a high variability in the effects of salinity on some specific lipid types. In cultured marine microalgae, hypersalinity affects lipid profiles more than hyposalinity. Growth restriction due to salt stress represents an important interaction that reduces productivity and often masks the direct effects of salinity on total lipid and triglyceride contents. Sulpholipids and phosphatidylglycerol are the lipid classes whose changes are most related to salinity, while knowledge about the response of phospholipids, betaine lipids and sterols is incipient. Among saturated fatty acids, salinity induces greater interspecific variability in 14:0 in comparison with 16:0 and 18:0. Monounsaturated fatty acids change the most with salinity. 18‐C polyunsaturated fatty acids tend to increase with salinity in marine microalgae and to decrease in freshwater species. Growing euryhaline microalgae in brackish water is a sustainable and favourable option to produce a variety of lipids of interest, including 20‐C and 22‐C polyunsaturated fatty acids with maximum nutritional value.

Neuroendocrine‐immune regulation mechanism in crustaceans: A review - Ruixue Tong; Luqing Pan; Xin Zhang; Yufen Li (Reviews in Aquaculture, 2022)
The development of aquaculture is closely related to human life. Crustaceans play essential roles in aquaculture. However, the cultivation of crustaceans has been plagued by various diseases, causing substantial economic losses. At present, the occurrence of shrimp diseases is directly related to environmental stress and physiological dysfunction, and especially environmental stress has become an important factor inducing diseases. Therefore, how to regulate the immune defence of crustaceans under environmental stress has become the primary problem in the prevention and control of shrimp diseases. The neuroendocrine‐immune system plays a vital role in maintaining homeostasis and enhancing environmental adaptability. Besides, in the evolutionary sense, with the theory that the nervous system and the immune system have a common origin put forward, the research on the neuroendocrine‐immune system of invertebrates has gradually become a hot spot. This review describes the evolution and communication mechanism of the neuroendocrine system and immune system in vertebrates and invertebrates, summarizes the characteristics of the neuroendocrine system and immune system in crustaceans, and focuses on how environmental stress affects the regulation of the neuroendocrine system on the immune system in crustaceans, as well as the influence of these regulations on host immune defence. This review also introduced the immune regulation of crustacean intestines under environmental stress and the effect of pathogen stress on crustacean immunity, hoping to lay a theoretical foundation for the follow‐up study of crustacean stress resistance and provide theoretical guidance for the healthy aquaculture of crustaceans.

Development of cod farming in Norway: Past and current biological and market status and future prospects and directions - Velmurugu Puvanendran; Atle Mortensen; Lill‐Heidi Johansen; Anne Kettunen; Øyvind J. Hansen; Edgar Henriksen; Morten Heide (Reviews in Aquaculture, 2022)
Atlantic cod is a historically abundant species in the North Atlantic region and has contributed to the prosperity of many nations. But a decline in stocks in the last century has prompted to initiate commercial farming of cod in captive conditions. Several approaches have been employed ranging from stock enhancement, capture‐based aquaculture and intensive cod farming. However, except for the enhancement efforts which were carried out for almost a century, efforts on other methods were intermittent coinciding with lower quotas. Intensive farming was attempted in Norway, Scotland, Ireland, Canada, Iceland and Faroe Islands in the 2000s. But it was carried out hastily to cash in the demand for cod in the market even though there were many biological knowledge gaps that are required for a successful aquaculture venture. The reasons for the failure of commercial farming in Norway during the 2000s were not only because of limited knowledge of the biology of cod but also the economic meltdown in Europe in 2008. Cod farming came to a halt; however, the Norwegian National Cod Breeding Program (NCBP) initiated in 2003 continued to operate and produced a fifth generation of a domesticated cod in 2019. Efforts to fill the gaps and the selective breeding for better growth and disease resistance within NCBP have improved the quality of the juveniles produced. We will discuss the past efforts and reasons for failure in farming of cod, how the current situation looks and the future direction in terms of cod biology, political atmosphere and market.

Submerged cage aquaculture of marine fish: A review of the biological challenges and opportunities - Michael Sievers; Øyvind Korsøen; Fletcher Warren‐Myers; Frode Oppedal; Georgia Macaulay; Ole Folkedal; Tim Dempster (Reviews in Aquaculture, 2022)
Surface‐based cages are the dominant production technology for the marine finfish aquaculture industry. However, issues such as extreme weather events, poor environmental conditions, interactions with parasites, and conflicts with other coastal users are problematic for surface‐based aquaculture. Submerged cages may reduce many of these problems and commercial interest in their use has increased. However, a broad synthesis of research into the effects of submerged culture on fish is lacking. Here, we review the current status of submerged fish farming worldwide, outline the biological challenges that fish with fundamentally different buoyancy control physiologies face in submerged culture, and discuss production benefits and problems that might arise from submerged fish farming. Our findings suggest that fish with closed swim bladders, and fish without swim bladders, may be well‐suited to submerged culture. However, for fish with open swim bladders, such as salmonids, submergence is more complex as they require access to surface air to refill their swim bladders and maintain buoyancy. Growth and welfare of open swim bladder fish can be compromised by submergence for long periods due to complications with buoyancy regulation, but the recent addition of underwater air domes to submerged cages can alleviate this issue. Despite this advance, a greater understanding of how to couple advantageous environmental conditions with submerged culture to improve fish growth and welfare over the commercial production cycle is required if submerged cages are to become a viable alternative to surface‐based cage aquaculture.

Cryptocaryon irritans (Brown, 1951) is a serious threat to aquaculture of marine fish - Yanwei Li; Biao Jiang; Zequan Mo; Anxing Li; Xueming Dan (Reviews in Aquaculture, 2022)
Cryptocaryon irritans (Brown, 1951) is an obligate parasite that mainly invades the skin, fins and gills of marine fish and causes marine ‘white spot disease’. It is common to aquarium and maricultured fish and causes high mortality due to its widespread geographical distribution, indiscriminate host specificity, short and simple life cycle, and high level of virulence. Numerous physical methods and chemical bath agents are applied to cure this disease in closed, re‐circulating aquaculture systems, but these treatments are not suitable in open environments such as cages and ponds. Fortunately, new measures, such as oral chemical drugs, oral plant components, vaccines and even biological control, are being developed as promising methods to treat and prevent cryptocaryoniasis in open aquaculture systems. Here, we provide a broad overview of C . irritans research, focussing primarily on work conducted in the last decade that may offer new insights into the treatment of disease in a practical setting.

The underexplored potential of green macroalgae in aquaculture - Anthony Moreira; Sónia Cruz; Rúben Marques; Paulo Cartaxana (Reviews in Aquaculture, 2022)
Green macroalgae (Chlorophyta) currently represent a residual fraction (

Habitat value of bivalve shellfish and seaweed aquaculture for fish and invertebrates: Pathways, synthesis and next steps - Seth J. Theuerkauf; Luke T. Barrett; Heidi K. Alleway; Barry A. Costa‐Pierce; Adam St. Gelais; Robert C. Jones (Reviews in Aquaculture, 2022)
Aquaculture can have negative environmental impacts, adding to the suite of anthropogenic stressors that challenge coastal ecosystems. However, a growing body of scientific evidence indicates that the commercial cultivation of bivalve shellfish and seaweed can deliver valuable ecosystem goods and services, including provision of new habitats for fish and mobile invertebrate species. We completed a systematic literature review of studies focused on understanding habitat‐related interactions associated with bivalve and seaweed aquaculture, and a brief meta‐analysis of 65 studies to evaluate fish and mobile macroinvertebrate populations at farms and reference sites. Bivalve and seaweed aquaculture were associated with higher abundance ( n = 59, range: 0.05× to 473×, median lnRR = 0.67) and species richness ( n = 29, range: 0.68× to 4.3×, median lnRR = 0.13) of wild, mobile macrofauna. Suspended or elevated mussel and oyster culture yielded the largest increases in wild macrofaunal abundance and species richness. We describe the major mechanisms and pathways by which bivalve and seaweed aquaculture may positively influence the structure and function of faunal communities—including provision of structured habitat, provision of food resources and enhanced reproduction and recruitment—and identify the role of the species cultivated and cultivation gear in affecting habitat value. Given the continued deterioration of coastal habitats and increasing investments into their restoration, understanding how industry activities such as aquaculture can be designed to deliver food within ecological limits and have positive influences on ecosystem goods and services is essential in ensuring ecological, social and economic objectives can be achieved.

Isotopic techniques in aquaculture nutrition: State of the art and future perspectives - Julián Gamboa‐Delgado (Reviews in Aquaculture, 2022)
Animal nutrition studies rely on traditional and advanced analytical techniques that have increased our understanding about the nutritional physiology of valuable species, leading to improved productivity, sustainability and further diversification. In the case of aquaculture nutrition, a vast amount of knowledge has accumulated in relation to different physiological responses elicited by experimental diets and feeding regimes. By measuring assimilation, inferences can be made about the specific dietary components that were digested, incorporated into tissue and used for metabolic functions. One of the most common methods applied to estimate assimilation consists of measuring stable isotope values at natural abundance levels in feeding items and consuming animals. Isotopic measurements have been of great assistance to identify nutrient sources contributing to the growth of larval and juvenile organisms. The techniques have also been useful to determine nutrient flows in several types of aquaculture systems. The present manuscript reviews the most recent applications and findings derived from studies that have used stable isotope analyses to (1) estimate nutrient assimilation in larval and juvenile organisms, (2) evaluate trophic dynamics and bioremediation potential of macroalgae and invertebrates in integrated multi‐trophic aquaculture systems and (3) investigate the trophic plasticity of aquatic species. The progressively more frequent application of compound‐specific isotope analysis of amino acids and fatty acids is emphasized as it has allowed exploring the physiological fate of specific organic compounds, while also assisting in the definition of nutritional requirements for aquatic species. Future nutritional applications of analytical techniques based on stable isotope measurements are addressed.

Acquired tetracycline resistance genes by transposons and virulence factors in enterococci recovered from overland and aquatic animals: A systematic review - Ebthag Almabruk Mohamed Mussa; Abdulsamad Alsalahi; Musheer A. Aljaberi; Azmiza Syawani Jasni; Mohd Nasir Mohd Desa; Abdullah Yahya Mohammed Al‐Mahdi; Rukman Awang Hamat (Reviews in Aquaculture, 2022)
Enterococci possess a high propensity to spread their resistance genes between intra‐ and inter‐species via mobile genetic elements. Potential reservoirs for acquiring antibiotic resistance genes by commensal and environmental bacteria, including enterococci, have raised significant public health concerns over recent decades. This concern is further complicated by the rampant use of tetracyclines in aquaculture and animals for therapeutic and chemoprophylactic purposes. This systematic review was conducted to elucidate the occurrence of tetracycline‐resistant enterococcal species, their resistomes and virulence determinants in faecal samples of aquatic and overland animals. The PubMed, Web of Science, ScienceDirect and Scopus databases were searched to retrieve relevant studies that matched the specific keywords. A total of 19 low‐bias studies were included. It was found that several tetracycline resistance genes such as tet (M), tet (L), and tet (M + L) genes encode for the ribosomal protection protein or for the efflux mechanism of tetracyclines in E. faecium , E. faecalis , E. hirae , E. durans , E . gallinarium and E. casseliflavus . Additionally, tet (M) and tet (M + L) or tet (M) genes were associated with transposons Tn 916 and/or Tn 5397 or Tn 1545 plus Tn 916 , respectively. The acquisition of tet (M) and tet (M + L) genes may be assisted by transposons Tn 916 and/or Tn 5397 or Tn 1545 plus Tn 916 . In conclusion, tetracycline‐resistant enterococci recovered from aquatic and overland animals could further complicate the management of antibiotic‐resistant bacteria in both humans and animals. Thus, a concerted, multisectoral and transdisciplinary approach (One Health) is needed for active surveillance to be exacted and for better public health measures to be initiated in the future.

Development, nutrition, and rearing practices of relevant catfish species (Siluriformes) at early stages - Enric Gisbert; Ronald Kennedy Luz; Ignacio Fernández; Pravata K. Pradhan; Maria Salhi; Mansour T. Mozanzadeh; Aditya Kumar; Yannis Kotzamanis; Diana Castro‐Ruiz; Martin Bessonart; Maria J. Darias (Reviews in Aquaculture, 2022)
Catfish (Siluriformes) are important species for aquaculture worldwide, with an annual production in 2018 of ca . 6 million t. This review focuses on reassessing larval development, first feeding, and early rearing practices of the most important farmed catfish species, along with some candidate species for aquaculture diversification: Pangasianodon hypophthalmus (Pangasiidae), Clarias gariepinus (Clariidae), Ictalurus punctatus (Ictaluridae), Pseudoplatystoma spp. (Pimelodidae), Heteropneustes fossilis (Heteropneustidae), Rhamdia quelen (Heptapteridae), Ompok bimaculatus (Siluridae), and Lophiosilurus alexandri (Pseudopimelodidade). These species are initially reared indoors from one day to two weeks and are then transferred to fertilised outdoor ponds where they either feed on natural zooplankton or compound feeds. With the exception of C. gariepinus , I. punctatus , R. quelen and P. hypophthalmus , consistent and reliable fry production is a bottleneck that limits the expansion of farming of other species, such as Pseudoplatystoma spp., H. fossilis , O. bimaculatus , and L. alexandri . Rearing systems (extensive, semi‐extensive, intensive) and feeding protocols vary with species and geographical regions. Cannibalism and size heterogeneity are common, and these features create problems for larval and fry rearing of catfish species. Information about their nutritional requirements is required for the formulation of compound feeds that can guarantee high survival and good growth of catfish fries. However, such knowledge for most species is scarce, although some data are available for I. punctatus . Further genomic resources might allow fine‐tuning rearing success. This review describes some successes in this field, and also highlights gaps in knowledge to guide future research that can promote the development of catfish aquaculture.

The loss of seed mussels in longline aquaculture - Paul M. South; Natalí J. Delorme; Bradley M. Skelton; Oliver Floerl; Andrew G. Jeffs (Reviews in Aquaculture, 2022)
The substantial loss of seed mussels during the early stages of longline aquaculture—often exceeding 95%—is a major issue that erodes the security and profitability of production while limiting the sustainable expansion of this industry in many parts of the world. There are many biological, environmental and procedural factors that potentially cause seed losses. The present understanding of these factors is highly limited, based on disparate lines of evidence and constrained by the challenges associated with quantifying the fate of minute organisms in the field. Addressing these knowledge gaps is a prerequisite for meeting the growing global demand for farmed seafood and requires significant and coherent research. We identify the diverse range of potential drivers of seed loss in mussel aquaculture and review existing knowledge around these factors to identify critical knowledge gaps and research priorities. Losses appear to be caused by a complex suite of interacting factors that include stress during transfer between regions, underlying variations in seed condition, change in the farm environment, predation, competition from biofouling organisms and migratory behaviour of seed mussels. Solutions to the losses of mussel seed in commercial culture are mostly likely to be achieved through research directed at evaluating a range of practical interventions during the critical phase of nursery culture of mussel seed.

The aquaponic principle—It is all about coupling - Gösta F. M. Baganz; Ranka Junge; Maria C. Portella; Simon Goddek; Karel J. Keesman; Daniela Baganz; Georg Staaks; Christopher Shaw; Frank Lohrberg; Werner Kloas (Reviews in Aquaculture, 2022)
The aquaponic principle is the coupling of animal aquaculture (e.g. fish) with plant production (e.g. vegetables) for saving resources. At present, various definitions of aquaponics exist, some bearing the risk of misinterpretation by dismissing the original meaning or being contradictory. In addition, there is no standard terminology for the aspects of coupling between the aquaponic subsystems. In this study, we addressed both issues. (1) We developed new or revised definitions that are summarised by: Aquaponic farming comprises aquaponics (which couples tank‐based animal aquaculture with hydroponics) and trans‐aquaponics, which extends aquaponics to tankless aquaculture as well as non‐hydroponics plant cultivation methods. Within our conceptual system, the term aquaponics corresponds to the definitions of FAO and EU. (2) A system analysis approach was utilised to explore different aquaponic setups aiming to better describe the way aquaponic subsystems are connected. We introduced the new terms ‘coupling type’ and ‘coupling degree’, where the former qualitatively characterises the water‐mediated connections of aquaponic subsystems. A system with on‐demand nutrient water supply for the independent operating plant cultivation is an ‘on‐demand coupled system’ and we propose to deprecate the counterintuitive term ‘decoupled system’ for this coupling type. The coupling degree comprises a set of parameters to quantitatively determine the coupling's efficiency of internal streams, for example, water and nutrients. This new framework forms a basis for improved communication, provides a uniform metric for comparing aquaponic facilities, and offers criteria for facility optimisation. In future system descriptions, it will simplify evaluation of the coupling's contribution to sustainability of aquaponics.

Environmental indicators in salmon aquaculture research: A systematic review - Megan E. Rector; Jenny Weitzman; Ramón Filgueira; Jon Grant (Reviews in Aquaculture, 2022)
The ecosystem approach to aquaculture (EAA) is a strategy for the sustainable development of the aquaculture sector, but the question of how it can be practically implemented remains unclear. Indicators that can be applied at relevant scales of impact and that reflect the environmental status and change offer a means of operationalizing EAA. Therefore, a systematic literature review was carried out to identify environmental indicators referenced in salmon aquaculture literature and review their potential to support EAA. Using the PRISMA method for selecting journal papers, 101 articles that included 531 indicators were reviewed. Indicators were characterized based on the effect of aquaculture they measure, their similarity to other indicators extracted, and the scale at which they were applied. Indicators and their characteristics are presented in a searchable online database. A scoring method for evaluating indicators based on criteria drawn from environmental indicator literature and the potential scalability of indicators to meet the needs of EAA was developed and applied to the most frequently referenced indicators. Overall, near‐field indicators of benthic impacts dominated salmon aquaculture literature. Of the most frequently referenced indicators, those that scored highest based on criteria drawn from environmental indicator literature also scored highest on scalability and therefore their potential contribution to EAA. Overall, results suggest that additional research and application of far‐field environmental indicators in salmon aquaculture will be required to identify a suite of indicators that can be applied as part of EAA practice.

Advances in practical feed formulation and adoption for hybrid grouper ( Epinephelus fuscoguttatus ♀ × E . lanceolatus ♂ ) aquaculture - Leo Nankervis; Jennifer M. Cobcroft; Nguyen V. Nguyen; Michael A. Rimmer (Reviews in Aquaculture, 2022)
Grouper aquaculture is currently trending towards production of hybrids, due to their improved growth and disease resistance. The predominant cross is between tiger grouper ( Epinephelus fuscoguttatus ) females and giant grouper ( Epinephelus lanceolatus ) males (TGGG). Sustainable TGGG aquaculture development is limited by reliance on wild‐caught ‘trash’ fish as feed rather than commercially formulated feeds. Specific TGGG nutrient requirement values remain limited, especially for larger fish that consume the highest volumes of feed. This limits the effectiveness of formulated feeds to provide optimal growth and feed conversion in an economically efficient manner. This review examines the current knowledge of hybrid grouper nutrient requirements for grow‐out feeds and identifies knowledge gaps to inform further research that will enable development of cost‐effective feeds that optimize fish growth, feed conversion and health. Current best practice in TGGG feeds specifies a relatively high protein requirement (53.5% crude protein), with higher arginine and lower lysine requirements than previously reported for grouper species. Like other groupers, the hybrid appears to require low lipid levels (10–14%); however, it remains to be elucidated whether this increases significantly with body size. The nutrient requirement data within this review provide a starting point for development of specific hybrid grouper feeds. However, commercialization of such feeds requires better understanding of the socio‐economic context of the target industry. While formulated feeds may be more cost‐effective, their implementation is limited by inferior growth compared with ‘trash’ fish. Performance gains are expected through increased understanding of size‐specific nutrient requirements and specific raw material quality criteria.

Analysis of spatial and temporal variations in bacterial community dynamics within stream biofilms - Anju Gautam; Gavin Lear; Gillian D. Lewis (New Zealand Journal of Marine and Freshwater Research, 2021)
Stream biofilms play an important ecological role in the supply of energy and organic matter to aquatic food webs. Bacterial community composition in stream biofilms is shaped by biotic interactions as well as physicochemical conditions which vary across space and time. However, knowledge of the relative importance of spatial versus temporal factors for microbial community composition is lacking. Here, we applied 16S rRNA gene sequencing to characterise the biofilm bacterial community composition of 732 stream biofilms. These biofilm samples were collected within six streams located a maximum of 118 km apart and draining different catchment types (forest, urban and rural land uses). Samples were collected at monthly intervals for 30 months over 2013–2015. Bacterial community composition was explained better by monthly changes (PERMANOVA; p p = 0.44). Bacterial community composition over months and years followed a discernible cyclical seasonal pattern, as quantified using periodic regression analysis. Temperature, TN, light, and soil moisture deficit were identified as factors most significantly correlated with seasonal variation in bacterial community composition. Overall, these findings suggest that temporal changes are more important than spatial changes across the scales investigated in this study.

Age structure, recruitment variation, and sex ratio in blue cod ( Parapercis colias ) subpopulations in New Zealand - Michael Peter Beentjes (New Zealand Journal of Marine and Freshwater Research, 2021)
Age compositions from eight blue cod ( Parapercis colias ) subpopulations off the South Island of New Zealand were compared to investigate recruitment patterns temporally and spatially. Findings indicate (1) recruitment is highly variable between years, (2) subpopulations closer to each other have similar age compositions, and (3) strong and weak recruitment events are linked and the key processes that drive recruitment strength are acting on a large spatial scale. Recruitment variability among years and similarities between areas are likely to be density‐independent, due to environmental fluctuations. Age compositions exhibited modal progression of age classes providing validation of ageing based on counts of rings on otoliths. Sex ratio by age and length were compared in relation to their reproductive strategy of changing sex from female to male (protogynous hermaphrodites). Sex ratio pattern differed for each of the eight subpopulations but was most similar in those from the same area. Males dominate at younger ages and sex ratio swings in favour of females with increasing age. Patterns in sex ratio with size are virtually the opposite to those of age because the largest fish are invariably males. These results support the theory that the form of protogyny in blue cod is diandric.

Review of life history parameters and preliminary age estimates of some New Zealand deep‐sea fishes - Peter J. McMillan; Alan C. Hart; Peter L. Horn; Dianne M. Tracey; Caoimhghin Ó Maolagáin; Brittany Finucci; Matthew R. Dunn (New Zealand Journal of Marine and Freshwater Research, 2021)
A literature review on longevity of New Zealand deep‐sea fishes provided life history parameter estimates for 17 bony and five cartilaginous species. Preliminary age estimates for a further nine deep‐sea bony fishes were made from otolith zone counts and included results from a pilot analysis of radiocarbon age estimates from the otoliths of three of the species. Radiocarbon age estimates corroborated the otolith zone count age estimates made for white rattail ( Trachyrincus aphyodes ) and smallhead cod ( Lepidion microcephalus ) but were substantially lower for the third species, smallscale brown slickhead ( Alepocephalus antipodianus ) which suggested that it was not exposed to elevated (near‐surface) levels of 14 C in early life. Validation of otolith zone age estimates is difficult for deep‐sea species but the radiocarbon analysis provided a practical method to corroborate age estimates for some bony fishes. Of the 31 fish in this study (known and new age estimates), five of the fishery target species and 10 of the bycatch were long‐lived (50 years or more). The hypothesis that all New Zealand deep‐sea species are long‐lived was not supported, but the chance of a species being long‐lived seem to be higher in deeper water.

Characterisation of constructed ponds and factors influencing their macroinvertebrate communities on the lower Waikato River floodplain, New Zealand - Jeremy Garrett‐Walker; Kevin J. Collier (New Zealand Journal of Marine and Freshwater Research, 2021)
Ponds are increasingly being constructed to enhance amenity values in human‐dominated lowland landscapes, but little is known of design features that influence macroinvertebrates which can provide important food resources for fish and waterbirds. We quantified pond characteristics, sampled benthic and water‐column macroinvertebrates in winter, and related abundance, biomass and community composition to characteristics of 34 ponds on the lower Waikato River floodplain, northern New Zealand. Compositionally different macroinvertebrate communities occupied water‐column and benthic habitats. Landscape setting had a significant effect on benthic composition in terms of biomass, while the independent effects of frequency of pond drying or flooding, respectively, influenced benthic (abundance, biomass) or water‐column (abundance) communities. Distance‐based linear models highlighted physicochemical conditions, water depth regimes and riparian vegetation composition as key variables accounting for dissimilarity in total macroinvertebrate biomass between ponds. Our results indicate that managing hydrological stability of ponds in terms of permanence and flooding influences the composition and biomass of invertebrate communities. Within this hydrological template, design of appropriate depth regimes and riparian conditions can enhance accrual of macroinvertebrate biomass, thereby increasing food resources for fish and waterbirds.

Sedimentary phosphorus in contrasting, shallow New Zealand lakes and its effect on water quality - Sean Waters; Piet Verburg; Marc Schallenberg; David Kelly (New Zealand Journal of Marine and Freshwater Research, 2021)
The eutrophication of lake ecosystems due to anthropogenic activities has impacted lakes worldwide and shallow lakes are particularly vulnerable. The retention of phosphorus (P) in lake sediments and its subsequent release to the water column is often a key factor in degraded water quality, algal blooms and delayed responses to lake restoration efforts. Despite this link between sedimentary P and poor ecosystem outcomes, a limited amount of research has been conducted on P dynamics in New Zealand's lakes. In this study, sediments in six shallow lakes across the country were analysed for geochemistry and P fractionation. Total sedimentary P content varied widely and was related to inflow concentrations and hydrological retention times. The P binding capacity of the sediments was related to iron (Fe) and aluminium (Al) concentrations, while the Fe:P ratio was correlated to the release of P under anoxic conditions. P fractions and release rates were poorly correlated with traditional water quality parameters, however the mobile‐P SL and reducible‐P fractions were strongly correlated with the frequency of summertime algal blooms. This relationship may provide an indicator to assess harmful algal bloom frequency in unmonitored lakes, and a valuable tool to assess internal loading risk and inform lake restoration methods.

Life histories of two hyperbenthic mysids (Mysidacea: Mysidae) in an open estuary - Beate M. Bierschenk; Carolyn W. Burns; Marc Schallenberg; Gerard P. Closs (New Zealand Journal of Marine and Freshwater Research, 2021)
Mysidae are widely distributed in aquatic ecosystems and form a large proportion of the hyperbenthic biomass in estuaries. The seasonality, spatial distribution and reproductive biology of the two hyperbenthic mysid species, Tenagomysis chiltoni and Tenagomysis novaezealandiae , were studied in an open estuary. Sampling was conducted bi‐monthly at night between February 2008 and April 2009. These two mysid species are spatially segregated along a salinity gradient, with T. chiltoni upstream and T. novaezealandiae downstream in the estuary. The life cycle and breeding dynamics of T. chiltoni (bivoltine life cycle) and T. novaezealandiae (multivoltine life cycle) were similar to those described in intermittently closed estuaries, but their breeding period (December to April) was relatively shorter and densities were lower. Life‐stage specific segregation in summer in both mysid species likely provided favourable conditions for maximum growth rates, short maturation times, and sheltering, enhancing reproductive success of both mysid species.

The release of legacy phosphorus from deforestation‐derived sediments in shallow, coastal lake Forsyth/Te Roto o Wairewa - Sean Waters; Jenny G. Webster‐Brown; Ian Hawes (New Zealand Journal of Marine and Freshwater Research, 2021)
Phosphorus (P) release from sediments accumulating since catchment deforestation, has been linked to algal blooms which have occurred in Lake Wairewa (Canterbury, NZ) for over a century. However, the mechanisms controlling this internal P loading are poorly understood. To address this issue, we investigated sediment P fractions, P release, dissolved oxygen (DO) and pH at the sediment–water interface, and undertook targeted water sampling. Sediment depth profiles of P fractions indicated surface enrichment (1600 mg P kg −1 ), which was due to an upward flux of P from legacy sediments deposited over at least the last 100 years. Phosphorus release under reducing conditions (0.75–64 mg P m −2 d −1 ) and pH >9.00 (3.27–11.07 mg P m −2 d −1 ) indicated the potential for internal loading. Low DO events ( −1 ) in bottom waters were short‐lived, and spatially discrete, although longer events (13 days) were observed. pH was variable (6.20–10.80), and prolonged periods of pH >9 (5–6 days) were recorded. Macrophyte beds were key drivers of low DO, elevated pH, and sedimentary P release. The results challenge the paradigm of well mixed shallow lakes and contribute to the knowledge required to understand shallow lake systems impacted by land‐use change.

High contribution of methane in greenhouse gas emissions from a eutrophic lake: a mass balance synthesis - Arianto B. Santoso; David P. Hamilton; Louis A. Schipper; Ilia S. Ostrovsky; Chris H. Hendy (New Zealand Journal of Marine and Freshwater Research, 2021)
Lakes are ‘hotspots’ for greenhouse gas (GHG) emissions, primarily carbon dioxide (CO 2 ) and methane (CH 4 ). Understanding the processes regulating GHG emissions from lakes, and their temporal variability, is essential for more accurately quantifying the role of lakes in global GHG cycles. In this study, we identified the processes that affect CO 2 and CH 4 concentrations in a small (0.3 km 2 ) eutrophic monomictic lake (Okaro, New Zealand). A mass balance model was used to calculate changes in CO 2 and CH 4 storage in the lake as a result of internal cycling and atmospheric fluxes. To support model computations, CO 2 and CH 4 concentrations profiles were measured monthly over a one‐year period, in addition to temperature, dissolved oxygen and chlorophyll a . Annually, Lake Okaro acted as a sink of CO 2 from the atmosphere (425.4 mmol CO 2 m −2 y −1 ) and a source of CH 4 (553.4 mmol CH 4 m −2 y −1 ) equating to a net GHG emission (diffusive fluxes of CO 2 and CH 4 combined) of 0.22 kg CO 2 ‐eq m −2 y −1 . Although it may be viewed as conservative and applies only to diffusive fluxes, our study indicates that eutrophic lakes with high rates of primary production may act as a net source of GHGs.

Characterisation of the expression of select genes in response to key marine pollutants in the triplefin Forsterygion capito - Diana Montenegro; Louis A. Tremblay; Zoë Hilton; Gavin Lear (New Zealand Journal of Marine and Freshwater Research, 2021)
Biomarkers in receptor species can be used to assess and monitor ecosystem health. This study aimed to develop mRNA biomarkers in the New Zealand triplefin Forsterygion capito and validate their induction in response to common estuarine contaminants. The targeted genes were cytochrome P450 1A ( cyp1a ), metallothionein ( mt ), vitellogenin ( vtg ), and cytochrome P450 aromatase ( cyp19b ). Fish were treated with intraperitoneal injections of benzo[a]pyrene (BaP), zinc, and 17β‐oestradiol (E 2 ). Levels of cyp1a were upregulated in the livers of fish exposed to BaP, and the vtg gene was up‐regulated in male fish exposed to E 2 . These results indicated that these two biomarkers in F. capito can be used to assess exposure to contaminants exerting similar mechanisms of toxicity.

Correlations between environmental conditions and Vibrio parahaemolyticus or Vibrio vulnificus in Pacific oysters from New Zealand coastal waters - Nicola J. King; Sarah Pirikahu; Graham C. Fletcher; Isabelle Pattis; Brian Roughan; Anne‐Marie Perchec Merien (New Zealand Journal of Marine and Freshwater Research, 2021)
Vibrio parahaemolyticus and Vibrio vulnificus can be found in oysters in coastal environments. Vibrio vulnificus can induce life‐threatening illness when ingested with oysters, while V. parahaemolyticus usually causes self‐limiting gastroenteritis. This study investigated correlations between concentrations of these Vibrio species in Pacific oysters from eight New Zealand coastal regions (2008–2017), and seawater surface temperature (SST), salinity and rainfall. In the pooled data, most (88%) of the oyster samples were collected during summer and autumn. The prevalence of V. parahaemolyticus and V. vulnificus was 85% and 15%, respectively. Vibrio vulnificus was always detected in the presence of V. parahaemolyticus . Across all regions, V. parahaemolyticus concentration positively correlated with SST ( r S = 0.60), but not with salinity ( r S = −0.01). Vibrio vulnificus concentration weakly correlated with SST ( r S = 0.26) and salinity ( r S = −0.21). Linear and generalised additive models were investigated but none were satisfactory for prediction. Salinity and SST explained V. parahaemolyticus concentrations, indicating that other environmental or biological factors contributed. When SST, salinity and rainfall 15 days prior to harvesting were investigated for one region, SST was the best pre‐harvest indicator for elevated concentrations of both Vibrio species.

Induction of metallothionein in the common bully ( Gobiomorphus cotidianus ) from the Motueka River - Louis A. Tremblay; Katherine Trought; Thomas J. Sheehan; Robin J. P. Holmes; Andrew Barrick; Roger G. Young (New Zealand Journal of Marine and Freshwater Research, 2021)
The Motueka catchment is a major river system in the South Island, New Zealand, typically considered to be of ‘good water quality’. The catchment has high metal inputs originating from a mineral belt in the headwaters. This study investigated the induction of metallothionein (MT) in the common bully, Gobiomorphus cotidianus , to assess exposure to trace metal contamination in the Motueka River. The results showed a significant increase in MT induction in both the gill and liver tissue samples from fish collected in the Motueka River compared to a reference site in the Brooklyn Stream tributary. This effect is likely modulated by the higher nickel levels originating from the Red Hills that accumulated in the sediment of the Motueka River.

Recolonisation of a fish and invertebrate community in a wetland following a drought: the importance of deep water refugia - Rose E. Stuart; Travis Ingram; Gerard P. Closs (New Zealand Journal of Marine and Freshwater Research, 2021)
Wetland restoration or re‐establishment is a common conservation goal, and the ability of a wetland community to recover from events such as drought are key to its long‐term success. At the mouth of the Waiau River in Southland, New Zealand, a series of wetland ponds have been created by diverting water from the river. A period of particularly low river flows resulted in the wetland drying out entirely, except for a few deep channels. A subsequent flood inundated the ponds, creating an opportunity to study recolonisation of the system. The deep channels provided an important refuge habitat for eels ( Anguilla spp.) during dry periods, with significantly higher numbers close to the channels immediately after refilling than at sites further away. Smaller fish ( Gobiomorphus and Galaxias spp.) took much longer to reappear in the ponds. The macroinvertebrate community showed no significant variation over the short term or up to a year post‐refill, although individually snail and water bug taxa increased and microcrustaceans decreased in abundance. Daphnia and ostracods were observed soon after refilling and dominated the community. This study highlights the importance of spatial heterogeneity in constructed wetland systems, as this habitat variation likely increases the recovery rate after drying.

Monitoring methods of feeding behaviour to answer key questions in penaeid shrimp feeding - Jean‐Benoît Darodes de Tailly; Jonas Keitel; Matthew A.G. Owen; Jose M. Alcaraz‐Calero; Mhairi E. Alexander; Katherine A. Sloman (Reviews in Aquaculture, 2021)
The penaeid shrimp farming industry is a fast‐growing sector which continues to suffer from significant feeding inefficiencies. Shrimp are slow to feed on pellets, with consumption dependent on a wide range of environmental and physiological parameters. Feed management on farms remains mainly based on feeding trays which can be difficult to observe and often result in overfeeding. While our understanding of shrimp feeding behaviour is beginning to improve under laboratory conditions, much less is known about shrimp behaviour in production ponds. Consequently, there is a growing interest within the industry to improve observations of shrimp feeding behaviour in situ , although this can be difficult due to high water turbidity and the benthic nature of shrimp. This review identifies key questions that remain unanswered in relation to shrimp feeding behaviour under commercial aquaculture conditions, and considers how they could be addressed using state‐of‐the‐art applications based on three technologies commonly used in other areas of aquaculture. The use of passive acoustics, computer vision and telemetry are highlighted, alongside their potential to help farmers achieve better feeding efficiencies and sustainability as well as to help understand shrimp feeding behaviour in relation to various biotic and abiotic parameters.

Applications of carbon nanotubes and polymeric micro‐/nanoparticles in fish vaccine delivery: progress and future perspectives - Sib Sankar Giri; Sang Guen Kim; Jeong Woo Kang; Sang Wha Kim; Jun Kwon; Sung Bin Lee; Won Joon Jung; Se Chang Park (Reviews in Aquaculture, 2021)
Newly evolving strains of pathogenic microorganisms in aquaculture are posing formidable challenge in controlling and/or eradication of diseases affecting aquaculture. Many research studies have aimed to address this challenge, and the delivery of vaccines using biocompatible nano‐delivery systems is widely investigated. Nanoparticles (NPs) have tremendous potential for application as delivery vehicles of novel vaccines. At present, various polymeric and non‐polymeric NPs are utilized to deliver vaccines in aquatic species. This review comprehensively discusses recent research advancements in the utilization of carbon nanotubes and polymeric micro‐/nanoparticles for the delivery of drug/nutrients to control fish diseases. Further, this review compares the potentials of various vaccine delivery systems utilized to control fish pathogens. The necessity of non‐toxic and eco‐friendly strategies for aquaculture has also been emphasized in this review.

Genome editing on finfish: Current status and implications for sustainability - Torill Bakkelund Blix; Roy Ambli Dalmo; Anna Wargelius; Anne Ingeborg Myhr (Reviews in Aquaculture, 2021)
Novel genome editing techniques allow for efficient and targeted improvement of aquaculture stock and might be a solution to solve challenges related to disease and environmental impacts. This review has retrieved the latest research on genome editing on aquacultured finfish species, exploring the technological progress and the scope. Genome editing has most often been used on Nile tilapia ( Oreochromis niloticus Linnaeus), followed by Atlantic salmon (Salmo salar Linnaeus). More than half of the studies have focused on developing solutions for aquaculture challenges, while the rest can be characterized as basic research on fish genetics/physiology or technology development. Main traits researched are reproduction and development, growth, pigmentation, disease resistance, use of trans‐GFP and study of the omega‐3 metabolism, respectively. There is a certain correlation between the species identified and their commercial relevance, indicating the relevance of most studies for present challenges of aquaculture. Reviewing geographical origin of the research, China has been in the forefront (29 publications), followed by the United States (9) and Norway (7). The research seems not to be dependent on regulative conditions in the respective countries, but merely on the purpose and objectives for the use of genome editing technologies. Some technical barriers identified in the studies are presented together with solutions to overcome these‐off‐target effects, ancestral genome duplication and mosaicism in F0. One of the objectives for use is the contribution to a more sustainable aquaculture, where the most prominent issues are solutions that contribute to minimizing impact on biodiversity.

Reviewing Pseudoloma neurophilia infections in the popular zebrafish model - Marta Caballero‐Huertas; Manu Soto; Laia Ribas (Reviews in Aquaculture, 2021)
Zebrafish is a worldwide used animal model to better understand cultured fish species; thus, in the last two decades, zebrafish facilities have been created in many aquaculture research centres. However, and despite the attempts of rigorous aseptic conditions for animal husbandry in wet laboratory facilities, the presence of parasites cannot be underestimated. The microsporidium Pseudoloma neurophilia , which mostly affects the central nervous system, has been listed as the most prevalent parasite in reared zebrafish. The emergence of P. neurophilia is usually detected when the individual presents irreversible morphological and/or behavioural symptoms, and consequently, the spread of the disease is inevitable, indicating that the infection is expanded across rearing tanks. This review attempts, for the first time, to collect and discuss the current information on P. neurophilia life cycle, target tissues and symptomatology of the infection occurred in zebrafish. Due to its vertical transmission together with the increasing presence of zebrafish as a model in reproduction‐related problems found in aquaculture, it is highlighted, among others, the sexual dimorphism of the pathogenic effects and the possible transgenerational implications of parasitic infections. Further, to date none effective treatments have been described, so here we provide in detail available diagnostic methods, discussing the importance of the early detection, giving safety‐rearing recommendations to decrease the presence of P. neurophilia . Our intention is to minimize parasite outbreaks in zebrafish facilities, which, on the one hand, can compromise zebrafish welfare, and on the other hand, could interfere furtively in the resulting research previously designed for improving aquaculture production but also other biomedical‐related research.

Sumithion usage in aquaculture: benefit or forfeit? - Md Shahjahan; SM Majharul Islam; Alif Layla Bablee; Muhammad A.B. Siddik; Ravi Fotedar (Reviews in Aquaculture, 2021)
Sumithion is an organophosphate insecticide, extensively used to remove tiger bug from aquaculture ponds prior to the release of fish larvae. Its usage in aquaculture may initially assist in insect eradication; however, the harmful effects of sumithion may surpass the beneficial effects and may be alarming for the farmed fish and other aquatic organisms. This study summarizes the consequential effects of sumithion on the natural productivity in aquaculture ponds, and early development, physiological response, and reproductive functions of the farmed fish. Studies have found that sumithion adversely affects the natural production of phytoplankton, zooplankton and benthos, and reduces the hatching success with increased mortality, and morphological alterations in fish embryos and larvae. Fish haematological and biochemical alterations are also reported to be induced by the exposure to sumithion, as are variety of histopathological alterations and reproductive dysfunctions in exposed fish. Overall, this study is the first comprehensive overview of any insecticide which may advance our understanding of the rational and restricted use of insecticide in aquaculture operations.

The expanding repertoire of immune‐related molecules with antimicrobial activity in penaeid shrimps: a review - Jude Juventus Aweya; Zhihong Zheng; Xiaoyu Zheng; Defu Yao; Yueling Zhang (Reviews in Aquaculture, 2021)
Shrimps live in a complex aquatic ecosystem with numerous other biotic and abiotic factors, especially pathogenic microorganisms, which require the adaptation of prudent protective and survival strategies. As invertebrates, shrimps reply on humoral and cellular innate immune response mechanisms for protection against pathogens. One integral part of the humoral innate immune defence mechanism involves many biomolecules that are constitutively expressed or induced by pathogens. Shrimps, therefore, produce various biomolecules and secondary metabolites for physiological and pathophysiological purposes, most of which also act as effector molecules in immune‐related functions. A growing number of molecules have been identified as essential constituents of the immune arsenal of biomolecules in penaeid shrimps. This review provides a synthesis of important information on penaeid shrimp‐encoded immune‐related molecules with antimicrobial activities, their molecular regulation and importance in shrimp innate immune response. Research gaps would be identified and proposed research themes emphasized for future studies.

Functional role of piRNAs in animal models and its prospects in aquaculture - Christy Lite; Vasisht Varsh Sridhar; Swati Sriram; Melita Juliet; Aziz Arshad; Jesu Arockiaraj (Reviews in Aquaculture, 2021)
The recent advances in the field of aquaculture over the last decade has helped the cultured‐fish industry production sector to identify problems and choose the best approaches to achieve high‐volume production. Understanding the emerging roles of non‐coding RNA (ncRNA) in the regulation of fish physiology and health will assist in gaining knowledge on the possible applications of ncRNAs for the advancement of aquaculture. There is information available on the practical considerations of epigenetic mechanisms like DNA methylation, histone modification and ncRNAs, such as microRNA in aquaculture, for both fish and shellfish. Among the non‐coding RNAs, PIWI‐interacting RNA (piRNA) is 24–31 bp long transcripts, which is primarily involved in silencing the germline transposons. Besides, the burgeoning reports and studies establish piRNAs' role in various aspects of biology. Till date, there are no reviews that summarize the recent findings available on piRNAs in animal models, especially on piRNAs biogenesis and biological action. To gain a better understanding and get an overview on the process of piRNA genesis among the different animals, this work reviews the literature available on the processes of piRNA biogenesis in animal models with special reference to aquatic animal model zebrafish. This review also presents a short discussion and prospects of piRNA’s application in relevance to the aquaculture industry.

Multistrain probiotics use in main commercially cultured freshwater fish: a systematic review of evidence - Javier Fernando Melo‐Bolívar; Ruth Yolanda Ruiz Pardo; Michael E. Hume; Luisa Marcela Villamil Díaz (Reviews in Aquaculture, 2021)
This review aims to explore developments in the usage of multistrain probiotics in commercial freshwater‐cultured fish and to address factors that affect the efficacies of multistrain probiotics to enhance growth parameters, survival after bacterial infection and immune modulation in comparison to monostrain probiotics. From bibliographic searches in Scopus, Web of Science and PubMed, it was possible to select 81 articles that evaluated multistrain probiotics supplementation during in vivo trials in Nile tilapia ( Oreochromis niloticus ), rainbow trout ( Oncorhynchus mykiss ), common carp ( Cyprinus carpio ) and roho labeo ( Labeo rohita ). Most of the articles showed different benefits, including enhancement of fish growth performance, immune response and resistance against some pathogenic bacteria, such as Aeromonas hydrophila , Streptococcus agalactiae and Streptococcus iniae . However, only 13 journal articles included a monostrain probiotic as a control that would allow direct comparison with a probiotic bacterial mixture to determine if the mixture offered higher benefits in comparison to a monostrain probiotic and a control group without probiotic supplementation. Here we explain the main findings, including the best probiotic mixtures, and some perspectives on multistrain probiotics research and use on a commercial scale.

The Macrobrachium rosenbergii nodavirus: a detailed review of structure, infectivity, host immunity, diagnosis and prevention - Ken Fong Chen; Wen Siang Tan; Lin Kooi Ong; Syafiq Asnawi Zainal Abidin; Iekhsan Othman; Beng Ti Tey; Ronald Fook Seng Lee (Reviews in Aquaculture, 2021)
The Macrobrachium rosenbergii nodavirus causes white tail disease, which primarily infects giant freshwater prawns, Macrobrachium rosenbergii . The infection leads to almost 100% mortality in post‐larvae, causing significant economic losses in aquaculture farms. To develop effective measures against outbreaks, a good understanding of the virus is essential. In this review, we discuss key aspects of the Macrobrachium rosenbergii nodavirus including its structure, mechanisms of transmission and infection and common strategies for detection and prevention of outbreaks. Structurally, cryogenic electron microscopy revealed that the nodavirus has a T = 3 icosahedral structure with dimeric blade‐like spikes on its surface. Homology modelling comparing wild‐type and enzymatically cleaved Macrobrachium rosenbergii nodavirus‐like particles revealed the significance of these spikes or protruding domains for binding. In vitro and in vivo studies have identified key aspects of Macrobrachium rosenbergii nodavirus infectivity, including (i) the viral binding targets such as transglutaminase and caveolin‐1, (ii) utilisation of B2‐like proteins in promoting infectivity and intracellular migration, (iii) replication mechanisms and (iv) co‐infection with the extra small virus. Though susceptible at a post‐larvae stage, adult Macrobrachium rosenbergii is immune to Macrobrachium rosenbergii nodavirus infection. During outbreaks, polymerase chain reaction and in situ hybridisation‐based detection techniques are commonly used to identify infected populations. Currently, the most useful strategies for an outbreak are physical biosecurity measures and prophylaxis such as vaccination and immunostimulants. Finally, critical gaps in research include development of immortalised shrimp cell models, elucidation of time‐resolved protein changes post‐infection and development of therapies to treat infections to mitigate economic losses during outbreaks.

Reproduction of greater amberjack ( Seriola dumerili ) and other members of the family Carangidae - Aldo Corriero; Matthew J. Wylie; Mitsuo Nyuji; Rosa Zupa; Constantinos C. Mylonas (Reviews in Aquaculture, 2021)
The family Carangidae contains several species of aquaculture interest, including the amberjacks, yellowtails and trevallies. Among them, the greater amberjack ( Seriola dumerili ), the Japanese amberjack or yellowtail ( Seriola quinqueradiata ) and the yellowtail kingfish ( Seriola lalandi ) are considered the species with the highest potential for commercial aquaculture. Understanding the reproductive physiology–biology, spawning kinetics and production characteristics in captivity are of utmost importance for the domestication of any animal, and developing broodstock management methods and therapies to optimize egg production and overcome potential reproductive dysfunctions are essential. The present article reviews the available literature on the reproductive biology of the Carangidae species of interest for the aquaculture industry, both in the wild and under farming conditions. The reproductive traits of wild and farmed fish, whenever available, were compared in order to improve the understanding of the reproductive dysfunctions occurring in captivity. Finally, the hormonal maturation and spawning induction protocols examined so far to ameliorate the reproductive dysfunctions and obtain fertile gametes are summarized, and their effectiveness in the different rearing conditions is discussed.

A review on sox genes in fish - Yacheng Hu; Binzhong Wang; Hejun Du (Reviews in Aquaculture, 2021)
The Sry‐related high mobility group box ( Sox ) genes family is a group of transcription factors playing crucial roles during reproduction and development. At least 50% amino acid sequences of Sox protein family are similarity to the sex‐determining region on the Y chromosome (Sry). The sox family exists throughout the invertebrates and vertebrates and plays an important role in sex determination and differentiation, gonadal development, neurogenesis, formation of multiple tissues and organs, early embryonic development, chondrocyte differentiation, cardio‐vascular system, and other features in fish. The full characters of sox genes at the genome‐wide level have been reported in many fish species, due to the rapid development of high‐throughput DNA sequencing technique and massive accumulation of genomic data. Here, the research progress of fish sox gene family is reviewed to provide the latest information for the research in this field.

Towards increasing production of genetically improved farmed types in aquaculture - Eric Hallerman; Alexandre Wagner Silva Hilsdorf; Devin M. Bartley; Graham C. Mair (Reviews in Aquaculture, 2021)

Nitrification and denitrification in recirculating aquaculture systems: the processes and players - Prasannan Geetha Preena; Vattiringal Jayadradhan Rejish Kumar; Isaac Sarojini Bright Singh (Reviews in Aquaculture, 2021)
One of the major challenges in any sustainable aquaculture production systems is the accumulation of nitrogenous waste such as ammonia and its biological nitrification products vi z nitrite and nitrate. Considering the bio‐security issues, amelioration of these wastes without water exchange can be accomplished only by way of establishing in situ nitrification and denitrification through biofilters/bioreactors activated with nitrifying/denitrifying bioaugmentors. In such systems, coexistence of aerobic denitrifiers, anaerobic ammonia oxidizers (Anammox) and complete ammonia oxidizers (Comammox) together with the autotrophic nitrifiers enhance the coupled nitrification–denitrification. This promotes total nitrogen removal without external carbon supplements or additional anerobic compartment in the system. Various recirculating aquaculture systems (RAS) comprise diverse nitrifying community in biofilters/bioreactors thereby imparting distinctive nitrogen conversion in the system. Meanwhile, the structure and population dynamics of the nitrifying/denitrifying consortia are influenced by the environmental factors forming the decisive factors of the success of the processes. Accordingly, understanding the complexity of nitrifying/denitrifying community composition turns out to be a requirement to facilitate its improvised performance. In this context, the review addresses different biological nitrogen removal systems, significance of nitrification–denitrification in RAS, genetic diversity of the key players in RAS, methods of analysis of their community structure, current application and prospects of the processes in RAS.

Commensal bacteria‐immunity crosstalk shapes mucosal homeostasis in teleost fish - Yong‐Yao Yu; Li‐Guo Ding; Zhen‐Yu Huang; Hao‐Yue Xu; Zhen Xu (Reviews in Aquaculture, 2021)
Fish harbour complex and dynamic microbiota in their mucosal surfaces. Due to the vital role of commensal microbiota in many biological functions including growth enhancement, nutrition, development, metabolism and immune response, many scholars have begun to refer to the microbiome as an ‘extended self’. Several studies have indicated that a normal microbiota contributes to fish health, and disturbances in microbial communities may lead to secondary infections and disease. Under evolutionary selective forces, fish have developed excellent innate immune mechanisms and an adaptive immune system composed of B cells and T cells to discriminate between beneficial and opportunistic bacteria for microbiome homeostasis. Many functional studies have demonstrated the involvement of immune cells, cytokines and Igs in maintaining microbiome homeostasis, and many beneficial microbes contribute to improving the immune barrier against external threats. Additionally, many host‐derived probiotics have been empirically used in the aquaculture sector and have been demonstrated to provide effective protection against fish diseases. Although little is known about the interactions between microbiota and the mucosal immune system in fish compared to mammals, managing aquaculture system microbiota may represent a promising alternative to antibiotics for disease prevention and control. This review thus provides an updated and comprehensive summary of currently characterized microbe compositions in fish mucosal tissues. Thereafter, the current knowledge on the crosstalk between microbiota and the mucosal immune system and probiotics in application is also discussed herein, thereby providing a theoretical basis for the development of microbe‐based disease control technologies in aquaculture.

The rise of the syndrome – sub‐optimal growth disorders in farmed shrimp - Rajendran Kooloth Valappil; Grant D. Stentiford; David Bass (Reviews in Aquaculture, 2021)
The phenomenon of slow growth in farmed shrimp was observed for the first time in 1989 in Penaeus vannamei as a clinical manifestation of runt deformity syndrome caused by infectious hypodermal and hematopoietic necrosis virus. Subsequently, it was recorded in Penaeus monodon during 2001–2002. Since then, the condition described as monodon slow growth syndrome (MSGS) has been reported from many countries. Though not leading to mortality, retarded growth at the pond level results in significant economic losses. Several potential pathogens have been identified from affected shrimp; however, no confirmed causal relationship has yet been established. Initially, P. vannamei farmed alongside slow growth‐affected P. monodon were unaffected by the condition. Further, experimental studies suggested that P . vannamei was not susceptible. However, in recent years, increasing incidence of severe growth retardation has been reported in farmed P. vannamei . Currently, slow growth is considered as one of the most impactful production‐limiting conditions affecting shrimp farming across Asia. Similar to MSGS, many infectious agents have been detected in slow growth‐affected P. vannamei , especially the microsporidian Enterocytozoon hepatopenaei . Further, genetic and environmental factors have been suggested to play a role. However, the exact cause of slow growth remains elusive, proposing that it may be a multi‐factor syndrome. This review tracks the trajectory of the condition over the period of significant expansion of shrimp farming and postulates that conventional single pathogen/single disease paradigms are insufficient to deal with chronic yield‐limiting syndromes. We suggest more realistic, multi‐dimensional aetiological consideration of syndromic and emerging diseases in shrimp aquaculture.

Stress management in aquaculture: a review of dietary interventions - Alexander Ciji; Mohammad S. Akhtar (Reviews in Aquaculture, 2021)
Over the last few decades, the demand‐driven growth in aquaculture has been tremendous due to development and adoption of cutting‐edge technologies and production systems such as intensification and high input aquaculture. This growth, however, has witnessed an insurgence of various environmental and husbandry‐related stressors posing major challenges to the aquaculture sector limiting its further expansion worldwide. These stressful conditions impair the health of cultured animals and predispose them to diseases resulting in economic losses. Hence, optimizing the stress resilience of the cultured species is paramount to ensure sustainable development of aquaculture sector. Addressing the concerns of stress mitigation in aquaculture, a plethora of research investigations have been intensively carried out all over the world targeting the management of cultured environment as well as cultured species. Among various mitigation strategies, dietary interventions appear to be pliable and a sustainable approach to develop immunocompetence and stress resistance in fish as requirement of several nutrients may increase under stressful conditions. The suboptimal and/or excessive levels of several essential and non‐essential nutrients modulate the immune response and stress/disease resistance. Hence, the present review is an inclusive and informative compilation of dietary interventions for management of stress in aquaculture. This review highlights the stress‐mitigating roles of different nutritive and non‐nutritive compounds/additives such as amino acids, essential fatty acids, phospholipids, vitamins, minerals, carotenoids, different synthetic chemicals and biological derivatives from bacteria, yeast, fungi, algae, plants and animals as a promising stress management strategy to enhance the overall performance of the cultured species.

Cover image - Mingkun Luo; Guoqing Lu; Haoran Yin; Lanmei Wang; Malambugi Atuganile; Zaijie Dong (Reviews in Aquaculture, 2021)

Offshore longline mussel farms: a review of oceanographic and ecological interactions to inform future research needs, policy and management - Llucia Mascorda Cabre; Phil Hosegood; Martin J. Attrill; Danielle Bridger; Emma V. Sheehan (Reviews in Aquaculture, 2021)
With a growing human population and the need to protect our oceans from overfishing, there is a requirement for society to source alternative means of sustainable protein. Mussel aquaculture has rapidly expanded in many countries serving as an important supply of protein, but its development has been limited due to competition for coastal space and the associated environmental impacts of farming in inshore waters. Offshore aquaculture developments have the potential to overcome such issues. This review synthesises the current literature on the ecological and oceanographic interactions of longline offshore mussel farms with the aim to elucidate the main knowledge gaps in a context of management and conservation. Large offshore aquaculture installations interact with the hydrodynamics of the area causing water flow distortions and current attenuation, wake formation and distorting water column stratification which can have an effect on the supply of nutrient and seston as well as altering material dispersal, biodeposition and resuspension, having in turn, a knock‐on effect on the carrying capacity of the system, ultimately affecting the surrounding ecology and its ecosystem services. Offshore mussel farm studies report an increase biomass or numbers of benthic and pelagic organisms beneath and around mussel ropes relative to control sites using the structure for shelter, refuge and nursery. Improving our understanding of offshore aquaculture–environment interactions is crucial to identify the priorities needed for future research to inform policy and management practices as well as its role as part of the Blue Growth Agenda and as ‘other effective area‐based conservation measures’ (OECMs).

A survey of fish behaviour quantification indexes and methods in aquaculture - Dong An; Jinze Huang; Yaoguang Wei (Reviews in Aquaculture, 2021)
In aquaculture, fish behaviour monitoring and analysis can provide the information required to guide daily feeding, schedule making and disease diagnosis. Technology such as machine vision, bio‐loggers and acoustic systems is essential to analyse fish behaviour. This paper focuses on tools and algorithms for fish behaviour quantification analysis. The goal is to present their basic concepts and principles, including the quantification analysis procedure and its potential application scenarios. This review shows that the most common behaviour quantification indexes can be categorised into three classes: swimming indexes, physical indexes and context indexes. Typically, swimming indexes are of the most interest to researchers. However, achieving comprehensiveness of the information and quantisation precision remain challenging in fish behaviour analysis. In brief, this paper aims to help researchers and practitioners better understand the current state‐of‐the‐art behavioural quantification analysis, which provides strong support for the implementation of intelligent breeding.

Optimizing hatchery practices for genetic improvement of marine bivalves - Jennifer C. Nascimento‐Schulze; Tim P. Bean; Ross D. Houston; Eduarda M. Santos; Matthew B. Sanders; Ceri Lewis; Robert P. Ellis (Reviews in Aquaculture, 2021)
Aquaculture currently accounts for approximately half of all seafood produced and is the fastest growing farmed food sector globally. Marine bivalve aquaculture, the farming of oysters, mussels and clams, represents a highly sustainable component of this industry and has major potential for global expansion via increased efficiency, and numbers of, production systems. Artificial spat propagation (i.e. settled juveniles) in hatcheries and selective breeding have the potential to offer rapid and widespread gains for molluscan aquaculture industry. However, bivalves have unique life‐histories, genetic and genomic characteristics, which present significant challenges to achieving such genetic improvement. Selection pressures experienced by bivalve larvae and spat in the wild contribute to drive population structure and animal fitness. Similarly, domestication selection is likely to act on hatchery‐produced spat, the full implications of which have not been fully explored. In this review, we outline the key features of these taxa and production practices applied in bivalve aquaculture, which have the potential to affect the genetic and phenotypic variability of hatchery‐propagated stock. Alongside, we compare artificial and natural processes experienced by bivalves to investigate the possible consequences of hatchery propagation on stock production. In addition, we identify key areas of investigation that need to be prioritized to continue to the advancement of bivalve genetic improvement via selective breeding. The growing accessibility of next‐generation sequencing technology and high‐powered computational capabilities facilitate the implementation of novel genomic tools in breeding programmes of aquatic species. These emerging techniques represent an exciting opportunity for sustainably expanding the bivalve aquaculture sector.

Recent development in ecdysone receptor of crustaceans: current knowledge and future applications in crustacean aquaculture - Muhammad‐Redha Abdullah‐Zawawi; Nor Afiqah‐Aleng; Mhd Ikhwanuddin; Yeong Yik Sung; Siriporn Tola; Hanafiah Fazhan; Khor Waiho (Reviews in Aquaculture, 2021)
Ecdysone receptor (EcR) is the primary regulator of the ecdysteroid signalling pathway, a critical pathway that directly links to moulting. In addition, EcR also regulates growth, development, reproduction and regeneration in crustaceans. However, there remains a huge gap of knowledge between the detailed structure and functional role(s) of crustacean EcR compared to that of insects. Motif and phylogenetic analyses of publicly available crustacean EcR proteins revealed the evolutionary relationship of EcR in this subphylum and highlighted its conserved characteristics among crustaceans. The role of EcR in the regulation of essential physiological processes in crustaceans including moulting, chitin synthesis, general growth and development, gonadal and maturation, and limb regeneration was discussed based on the available literature. This essential moult‐related nuclear receptor could serve as a useful molecular indicator of moulting and gonadal maturation, as a potential target for pesticide production against parasitic crustacean species in the aquaculture industry, as well as valuable bioindicators of environmental stressors.

Comprehensive update on inventory of finfish cell lines developed during the last decade (2010–2020) - Raja Swaminathan Thangaraj; Lekshmi Narendrakumar; Preena Prasannan Geetha; Arun Raja Shanmuganathan; Arathi Dharmaratnam; Sundar Raj Nithianantham (Reviews in Aquaculture, 2021)
Cell culture has become an indispensable part of modern research and is considered the best alternatives for different biological research on whole animals as they mimic the host cellular genetic homogeneity and also reduces the variability of in vivo responses. Hence, there has been increasing development of cell lines by different research groups and companies globally. For this reason, to cover the dearth of knowledge of newly developed fish cell lines, we have made a comprehensive update on new fish cell lines established in the past decade (2010–2020) to reflect the number of cell lines now available. This review focuses on the appraisal of the literature and of work done in finfish cell culture around the globe during the last decade and summarizes 280 newly established fish cell lines derived from 20 different tissue types of 44 fish families belonging to 21 different countries raising the total finfish cell lines to 783. The highest number of cell lines developed in the past decade was from the fish of the family Cyprinidae, which are most widely cultured in Asian countries. Also, the review discusses the need of new cell line development, different methods of cell line development and further enumerates the various applications and future prospects for these cell lines which we believe will serve as a referral document for researchers in the field.

Issue Information (Reviews in Aquaculture, 2021)

Virulence mechanisms of vibrios belonging to the Splendidus clade as aquaculture pathogens, from case studies and genome data - Weiwei Zhang; Chenghua Li (Reviews in Aquaculture, 2021)
The Vibrio genus belonging to the Splendidus clade includes 16 described species and can infect a broad host range of cultured animals in marine environments, resulting in various diseases and high mortality, thus leading to high economic losses in aquaculture. Here, we provide a brief description of the virulence of Splendidus clade pathogens and the known or potential virulence factors as well as the virulence regulation factors provided by both case studies and genome data. Splendidus clade pathogens possess virulence factors, including adhesins, extracellular proteases, haemolysins and siderophores, to adhere to, invade and combat hosts. Global regulators, such as the quorum sensing system and σ factors, are involved in virulence regulation. Chemotaxis, flagellum, secretion and toxin‐antitoxin systems, as well as small RNAs that are frequently involved in virulence, are also included in the discussion of the genome data of Splendidus clade pathogen. A better understanding of the pathogenesis, virulence factors and virulence regulation will not only illustrate the means used by Splendidus clade pathogens to infect their hosts but also offer new targets for the development of control strategies against Splendidus clade pathogen infection in aquaculture.

Fish pigmentation and coloration: Molecular mechanisms and aquaculture perspectives - Mingkun Luo; Guoqing Lu; Haoran Yin; Lanmei Wang; Malambugi Atuganile; Zaijie Dong (Reviews in Aquaculture, 2021)
Fish coloration, evolved from selection and adaptation, is a prominent feature of remarkable aquaculture merits. Fish possess more pigment cell types than any other vertebrates and are an excellent model for the study of mechanisms underlying skin coloration and pigmentation at levels from molecular genetics to system biology. How to effectively improve skin colour in ornamental and aquaculture fish has long been a focus on selective breeding programmes. In this review article, we introduce different types of chromatophore and early development of pigmentation, describe cellular mechanisms related to morphological and physiological changes of body colour and demonstrate applications of single‐sex control and molecular marker–assisted breeding in body colour selection. We also reviewed genes that have been found involving in neural crest migration and development, as well as those involved in melanin‐based coloration and other types of pigmentation, and explored how to use transgenic technology for enhancing fish body colour. The applications of genome editing and other omics technologies in relation to fish coloration are also illustrated. Finally, we present our perspectives about future fish coloration research and practice in aquaculture. Taken together, this review is expected to provide an update on cellular and molecular mechanisms in fish coloration and pigmentation, which will likely promote body colour–based molecular breeding programmes in aquaculture.

Immunomodulation by dietary supplements: A preventive health strategy for sustainable aquaculture of tropical freshwater fish, Labeo rohita (Hamilton, 1822) - Akruti Gupta; Sanjay Kumar Gupta; Manisha Priyam; Muhammad A.B. Siddik; Neeraj Kumar; Prashant Kumar Mishra; Kishore Kumar Gupta; Biplab Sarkar; Tilak Raj Sharma; Arunava Pattanayak (Reviews in Aquaculture, 2021)
Dietary supplementation is an effective strategy for boosting the innate immune response in fishes. It involves the use of functional ingredients that bear the potential for mitigating the deleterious effects of chemotherapeutics (bioaccumulation and development of drug‐resistant pathogens), as a more ecologically responsible approach to fish farming. With the emergence of probiotics, prebiotics, synbiotics and herbal immunostimulants; dietary supplementation has become an integral aspect of immuno‐nutrition. In this review, we have compiled a list of dietary immunostimulants in rohu, based on the research carried over the last ten years. It should be noted that nearly 25% of the studies on dietary supplementation in Labeo rohita investigated probiotics species (either singly or as mixtures), followed by the use of herbal supplements or phytobiotics. In relation to stress, about 30% of the studies dealt with the supplementation of tryptophan, followed by the incorporation of lipotropes. Moreover, approximately 55–60% of the studies reviewed, were restricted to nutrition‐based disease resistance against Aeromonas hydrophila infection. Commercially available probiotics and herbal feed additives have been helpful in the health management of L. rohita to some extent. Ongoing research is consistently exploring novel ingredients inducing favourable immunomodulation to survive stress and widespread A . hydrophila infection in L . rohita . However, further investigations aiming at broad‐spectrum disease resistance and multiple stress resilience are recommended. Efforts must also be directed towards the elucidation of specifically targeted response in vivo. Overall, greater insights into the molecular mechanisms of dietary supplementation of immunostimulants warrants the use of downstream analytical techniques and high‐throughput screening tools.

Opportunities for microbiome research to enhance farmed freshwater fish quality and production - Lara Parata; Jesmond Sammut; Suhelen Egan (Reviews in Aquaculture, 2021)
Freshwater fish farming is the largest sub‐sector of the global aquaculture industry, with its continued success dependent on the industry’s ability to be productive and sustainable. In recent years, microorganisms have been increasingly recognised for their role in the health and overall performance of aquatic organisms, providing the aquaculture industry with a promising avenue for further success. Here, we review the literature on freshwater fish microbiology to evaluate the potential for microbial research to enhance freshwater aquaculture. A systematic review revealed that the existing freshwater fish microbiology literature incorporates

Adiponectin’s roles in lipid and glucose metabolism modulation in fish: Mechanisms and perspectives - Renlei Ji; Xiang Xu; Giovanni M. Turchini; Kangsen Mai; Qinghui Ai (Reviews in Aquaculture, 2021)
Glucose and lipid metabolisms are central in determining the growth and the health status of cultured fish and thus are of pivotal interest for modern aquaculture. Adiponectin is a fat‐derived hormone that plays a vital role in glucose and lipid homeostasis. While abundant knowledge is available on adiponectin in mammals, less is known in fish, though it has been documented that adiponectin is certainly important in the modulation of teleosts’ lipid and glucose metabolism too. Adiponectin exerts its metabolic effects via two receptors, AdipoR1 and AdipoR2, which then, in a tissue‐dependent manner, initiate a series of signal transduction events, eventually resulting in increased glucose utilization and fatty acid β‐oxidation. In teleosts, adiponectin and its receptors genes were first identified in zebrafish in 2008, and since then, increasing numbers of adiponectin and its receptors have been cloned in a variety of cultured fish species. This review attempts to provide the first, thorough overview of the discovery and identification of adiponectin, its receptors and their expression, regulation and signal transduction in fish. Then, the potential effects and mechanisms of adiponectin on energy (lipid and glucose) homeostasis are described, before concluding on possible therapeutic approaches to enhance adiponectin actions. It is envisaged that the present work will contribute, first, to knowledge gain in the evolution of energy homeostasis in vertebrates, and then, to provide a much‐needed additional theoretical fundament for a healthier and further performance‐improved aquaculture.

Genetic improvement technologies to support the sustainable growth of UK aquaculture - Tim Regan; Tim P. Bean; Tim Ellis; Andrew Davie; Stefano Carboni; Herve Migaud; Ross D. Houston (Reviews in Aquaculture, 2021)
While the UK is the fourth largest aquaculture producer in Europe by volume, it is the second largest by value with an annual first sale value of around £1 billion. Over 90% of this value is from Atlantic salmon farmed in Scotland, but other finfish and shellfish aquaculture species are important to several UK regions. In this review, we describe the state of the art in UK aquaculture breeding and stock supply, and how innovation in genetics technologies can help achieve the Scottish Government’s ambitious target of doubling its aquaculture industry by 2030. Particular attention is given to the four most important UK aquaculture species: Atlantic salmon, rainbow trout, blue mussel and Pacific oyster, and we contrast the highly variable level of selective breeding and genomics technologies used in these sectors. A major factor in the success of Atlantic salmon farming has been large‐scale investment in modern breeding programmes, including family selection programmes and genomic selection. This has proven cost‐effective at scale, leading to improved production efficiency and reduction of some infectious diseases. We discuss the feasibility of applying similar technologies to the UK shellfish sectors, to ensure consistent and robust spat supply and begin trait selection. Furthermore, we discuss species‐specific application of modern breeding technologies in a global context, and the future potential of genomics and genome editing technologies to improve commercially desirable traits. Increased adoption of modern breeding technologies will assist UK aquaculture industries to meet the challenges for sustainable expansion, and remain competitive in a global market.

Sustainable aquaculture development: a review on the roles of cloud computing, internet of things and artificial intelligence (CIA) - Umar Farouk Mustapha; Abdul‐Wadud Alhassan; Dong‐Neng Jiang; Guang‐Li Li (Reviews in Aquaculture, 2021)
Each year, there is a significant rise in demand for global food production due to population increase and a rise in demand for protein food sources. This puts pressure on capture fishery as fish is a preferred protein source worldwide. However, the more resources we put into the capture fisheries to obtain maximum catch, the faster the fisheries stock becomes depleted. The best option left to produce enough fish to meet demand is relying on advanced aquaculture. Unfortunately, the impact of technological advancement in the aquaculture sector is not profound compared to the agricultural and manufacturing sectors. The advent of Cloud computing, Internet of Things, and Artificial Intelligence (CIA) has expanded numerous possibilities for applying and integrating information technology in all works of life. This article reviews the emergence of research development on CIA and the potential to revolutionize the aquaculture industry. The use of CIA techniques and tools such as drones, nano and micro‐sensors, bionic robots, remote cameras, intelligent sorting, energy‐saving processing equipment, statistical modules, and algorithms will reduce human intervention and increase aquaculture productivity. Also, the application of CIA in the aquaculture value chain to ensure effectiveness in traceability, feeding, disease detection, growth prediction, environmental monitoring, market information, and others is key to increasing aquaculture productivity and sustainability. Therefore, the future of aquaculture operations with less human labour, effective maintenance, and resource utilization largely depend on innovative technologies. Here, we outlined the need for adopting innovative technologies and the limiting factors that hinge on CIA adoption in the aquaculture industry.

Testicular development and spermatogenesis in fish: insights into molecular aspects and regulation of gene expression by different exogenous factors - Irfan A. Bhat; Jaffer Y. Dar; Irshad Ahmad; Ishfaq N. Mir; Hussna Bhat; Raja A.H. Bhat; Parvaiz A. Ganie; Rupam Sharma (Reviews in Aquaculture, 2021)
In fish, as in higher animals, the normal ontogenesis of the gonads is the basis for successful reproduction. Gonadal differentiation and development depend on the genetic cascade that programmes the events. Eventually, gonads become the sites for the maturation of gametes, which are originally derived from the primordial germ cells (PGCs) and form the cellular basis of reproduction. In fish hormones of the hypothalamic–pituitary–gonadal (HPG) axis regulate reproduction and fertility by promoting or inhibiting the production of gonadal sex steroids and their function. Gonadal sex steroids not only guide proper gonadal development and function but also play a key role in the activation and regulation of the HPG axis through two feedback control systems. In this review, we discuss the general outline and expression pattern of the major genes involved in testicular development and gonadal steroidogenesis in fish. The review attempts, for the first time, to collect and discuss recent information regarding the regulation of sex differentiation and steroidogenic genes during the stages of testicular development and in response to different external factors. Furthermore, clear insights into the important genes and their regulation involved in the HPG axis and spermatogenesis are presented briefly. This review can serve as a guide for fish breeders on the substances that have a positive impact on reproduction in males.

Genetic improvement for aquaculture species: A promising approach for aquaculture challenges and development - Zhen‐Yu Du; Pin Nie; Jiashou Liu (Reviews in Aquaculture, 2021)

Seasonal reproduction of the blue mussel ( Mytilus galloprovincialis ) from two locations in southern New Zealand - Daniel C. Smart; Samuel Heenan; P. Mark Lokman; Miles D. Lamare (New Zealand Journal of Marine and Freshwater Research, 2021)
Blue mussels, Mytilus galloprovincialis, are a widespread and ecologically important species in New Zealand coastal ecosystems, yet, there is limited information on the seasonality and variability in reproduction among populations. The reproductive cycle of M. galloprovincialis was studied monthly over 1‐year in two southern New Zealand populations (Aramoana (45.7787°S, 170.7037°E) and Timaru (44.3905°S, 171.2498°E)). Tissue indices were determined, and gonads examined histologically. At both sites, males and females displayed synchronous changes in condition indices and gonad indices, with both indices generally greater in the Timaru population than in the Aramoana population. Both sampling sites presented with comparable seasonality of reproduction with spawning over spring and summer months (September to February). Gametogenic development occurred over the autumn and early‐winter period (March to August). Spatial differences in reproduction coincided with differences in phytoplankton food abundance (greater in Timaru), while there were only small differences in sea temperatures between sites. This study indicates the likelihood of spatial variation in reproductive biology between M. galloprovincialis populations, even across small spatial scales (

Overview of the comb jellies (Ctenophora) from the South‐western Atlantic and Sub Antarctic region (32–60°S; 34–70°W) - Agustín Schiariti; Maria Sofía Dutto; Otto M. Oliveira; Gabriela Faillia Siquier; Francisco Alejandro Puente Tapia; Luciano Chiaverano (New Zealand Journal of Marine and Freshwater Research, 2021)
Ctenophora are important components of marine ecosystems. However, the South‐western Atlantic and Sub Antarctic region are still one of the least studied region in the world. We report the species composition and spatial distribution of Ctenophora and reviewed the studies performed in this region. New data obtained between 1910 and 2019, encompassing an area of c. 7 million km 2 (32–60°S, 34–70°W) were presented and published information was added. We confirm the occurrence of nine taxa, seven of which have been previously reported in the region. Mnemiopsis leidyi and Pleurobrachia pileus were the most frequent and numerous species. Beroe ovata was frequently observed but reaching high numbers only occasionally. Beroe cucumis was always observed in low numbers. Callianira antarctica , Lampea pancerina and Mertensia ovum have been reported few times as single individuals. Eurhamphaea and Beroe sp. were found for the first time in the study region. This overview represents the state of the art in ctenophore research for the studied region, providing new knowledge on species composition and patterns of spatial distribution in the area.

Decadal population dynamics of an intertidal bivalve ( Austrovenus stutchburyi ) bed: pre‐ and post‐ a mass mortality event - Karen A. Tricklebank; Roger V. Grace; Conrad A. Pilditch (New Zealand Journal of Marine and Freshwater Research, 2021)
Three independent annual surveys with some spatial–temporal overlap were amalgamated to describe the population dynamics of the New Zealand intertidal cockle ( Austrovenus stutchburyi ) at Lews Bay, Whangateau Harbour from 1997–2018. After more than a decade of relative stability there was a dramatic decline in the biomass (from 7.4 to 1.8 kg wet weight m −2 ), density (1049 to 409 individuals m −2 ) and mean length (22.5 to 17.7 mm) of cockles following a mass mortality event in 2009. Large (≥30 mm) cockles were more severely impacted by the die‐off, suffering mortality rates of more than 80%, compared with approximately 44–55% for cockles A . stutchburyi at two survey sites has steadily increased, and at one of these sites has recovered close to pre‐2009 densities. However, the density of large cockles has not increased since 2009, and the mean shell length has remained stable at 17.9 mm despite protection from harvesting. This hysteresis in the recovery of population size structure suggests exceptionally slow growth rates, high mortality of young adult cockles or a change in environmental conditions that no longer supports large individuals.

The effects of broodstock generation on ova fatty acid profile in Giant Kokopu Galaxias argenteus - Luu Huong Hoang; Julian Lilkendey; Armagan Sabetian (New Zealand Journal of Marine and Freshwater Research, 2021)
The ability of different broodstock generations to provision lipids to their gametes is often overlooked in aquacultured freshwater fish. In this study we investigated the ability of two generations (F1 & F2) of Giant Kokopu ( Galaxias argenteus ) to provision fatty acids into their eggs. Here we show that eggs of captive‐bred females (F2) displayed different relative fatty acid concentrations compared with eggs of females bred from wild fish (F1). F2 generation eggs showed significantly lower total mono unsaturated fatty acids (MUFA) concentration, predominantly through lower C18:1( n −9) Oleic acid, and higher total poly unsaturated fatty acids (PUFA) concentration, predominantly through higher 22:6( n −3) docosahexaenoic acid [DHA]. Furthermore, Oleic to n −3 fatty acid ratio, and Oleic to DHA ratio, both declined significantly from F1 to F2 generation. Our results suggest an elevated capacity of F2 females to provision better ratios of essential fatty acids during reproduction, most likely due to a transgenerational adaptive response, either to the fed diet or to a predictable laboratory environment. The findings of this study have important implications for aquaculture management in new captive freshwater species, particularly in aiding identification of more adapted broodstock generations.