Microplastic pollution in urban streams across New Zealand: concentrations, composition and implications - Aidan K. Mora‐Teddy; Christoph D. Matthaei (New Zealand Journal of Marine and Freshwater Research, 2020)
Microplastic pollution in aquatic systems has been reported globally at an alarming rate, with an increasing number of documented negative biological consequences. Research on microplastic pollution in freshwaters has barely begun in New Zealand, and few studies from smaller lotic systems such as streams exist globally. We investigated the extent of microplastic pollution within urban streams across New Zealand and determined if microplastic concentrations were related to human population density and urbanisation of streams. Fifty‐two streams were surveyed across five urban agglomerations in January 2019. Microplastics were found in samples from all sites at densities ranging from 3 . This concentration range was comparable to global data but lower than reported in another recent New Zealand study, probably due to differences in sampling methodology. Microplastic pollution was similar across all urban centres, and neither length of urbanised catchment nor urban proportion of the stream were significant predictors of microplastic concentrations. These findings suggest microplastic pollution in New Zealand streams are comparable to larger aquatic systems globally, and that smaller urban streams are significant transport pathways for microplastics. We also recommend standardising microplastic sampling methods to a greater extent in the future, to improve comparability across studies.

Acoustically estimated size distribution of sperm whales ( Physeter macrocephalus ) off the east coast of New Zealand - Giacomo Giorli; Kimberly T. Goetz (New Zealand Journal of Marine and Freshwater Research, 2020)
The length‐frequency distribution of sperm whales ( Physeter macrocephalus ) was studied on the east coast of NZ using passive acoustic recorders moored offshore of Kaikoura, Cape Palliser and Castlepoint. Sperm whale’s echolocation signals are unique among odontocete species. Their clicks are composed by multiple pulses resulting from the sound transmission within the whale head. The total length of the whales can be estimated by measuring the time delay between these pulses. A total of 997 length measurements were obtained from click trains using cepstral analysis (mean = 14.6 m; min = 9.6 m; max = 18.3 m; std = 1 m). The size‐frequency distributions at all three locations were similar, although animals smaller than 12 m were not present offshore of Kaikoura. Animals of various sizes appeared to be present all year round, with no apparent seasonality in the occurrence of any size class.

High levels of site fidelity in movement patterns of Southern Rock Lobster ( Jasus edwardsii ) in Victoria, Australia - Alexandra Skeer; Adrian Linnane; David Reilly; Charlie Huveneers (New Zealand Journal of Marine and Freshwater Research, 2020)
Movement patterns of the Southern Rock Lobster Jasus edwardsii in Victoria, Australia were investigated from 8,533 tag‐recapture events across a 20‐year period (1992–2012). In total, 83% of lobsters were recaptured within 1 km of their tagging site and 93% within 5 km. While largely resident, elevated movements were observed within specific regions, with the overall direction of movement being from inshore to offshore areas. Movement was not impacted by lobster sex, size, or reproductive stage. The fishery for Southern Rock Lobster within Victoria is currently managed into two zones with separate total allowable commercial catches in each area. Given the high levels of site fidelity, our findings suggest that management of the resource at this spatial scale is appropriate and that consideration of significant movement between zones is not warranted in fishery stock assessment models.

Community volunteer assessment of recreational water quality in the Hutt River, Wellington - Amanda E. Valois; Juliet R. Milne; Mark W. Heath; Rob J. Davies‐Colley; Emily Martin; Rebecca Stott (New Zealand Journal of Marine and Freshwater Research, 2020)
Water is an important component of many recreational opportunities and New Zealand invests significant resources in recreational water quality (RWQ) monitoring to assess risks to public health. However, monitoring primarily focuses on microbiological hazards and RWQ is considerably broader than this. The goal of this study was to take a comprehensive approach to evaluating RWQ while exploring the potential for greater public involvement in monitoring. A popular river swimming site was co‐monitored weekly by volunteers and a council field officer. The attributes monitored–water temperature, visual clarity, benthic cyanobacteria and filamentous periphyton cover, E. coli and rubbish–were identified from a volunteer workshop. There was good concordance between volunteer and council data suggesting that volunteer measurements can be considered reliable. This highlights the potential for volunteers, with professional support, including training and quality assurance, to extend council RWQ surveillance to additional monitoring sites while improving public engagement on water management.

Otolith shape as a stock discrimination tool for ling ( Genypterus blacodes ) in the fjords of Chilean Patagonia - Rodrigo Wiff; Andrés Flores; Angel M. Segura; Mauricio A. Barrientos; Vilma Ojeda (New Zealand Journal of Marine and Freshwater Research, 2020)
Genypterus blacodes, in terms of its fishing history and local economic importance, is an emblematic species harvested in Chilean Patagonia (41°00’–57°00’S). Most of the current fisheries and biological knowledge of this species come from the open ocean, whereas information about the species in fjords and inner channels is fragmentary. In 2018, two research surveys targeting G. blacodes were conducted in the fjords and inner channels of Chilean Patagonia. A total of 253 pairs of sagittal otoliths were sampled at three different localities, and their contours were modelled using wavelet analysis as a tool for stock discrimination. Contours were compared using canonical analysis, and classification was performed using linear discriminant and Random Forest analyses. The results indicated that the wavelet method is efficient in modelling otolith contours, and the discriminant analyses showed differences among fishing grounds across the latitudinal gradient, thus confirming the hypothesis that G. blacodes conform to at least two separate stock units in Chilean Patagonia. Fishing grounds that were closer in space showed higher levels of misclassification. The discussion focuses on how environmental variables and the geography of fjords shape stock differences and how this information can be used for the sustainable management of G. blacodes .

First record of Bonnemaisonia hamifera (Bonnemaisoniales, Rhodophyta) in the South Pacific, from the South Island of New Zealand - David J. Garbary; Roberta D’Archino; Brendan Flack; Christopher D. Hepburn; Wendy A. Nelson; Daniel Pritchard; Judy. E. Sutherland (New Zealand Journal of Marine and Freshwater Research, 2020)
The tetrasporophytic ‘ Trailliella ’ stage of the red algal genus Bonnemaisonia is reported for the first time from the Southern Hemisphere. Here we describe a bloom of the tetrasporophyte of B. hamifera from the mouth of the Waikouaiti River, Karitāne, South Island, where it occurred as thousands of free‐floating tufts up to 1 cm wide in shallow water, accumulated in windrows on sand banks and beaches, and in the water column at depths of 10–12 m on the adjacent open coast. Gametophytic stages have not yet been found in New Zealand. The material collected to date is strictly vegetative, and reproduction occurs via fragmentation. The identity of the New Zealand samples as B. hamifera was confirmed by both morphology and rbc L sequencing. The abundance and floating dispersal of B. hamifera suggests that it is invasive and will become widely distributed in New Zealand.

Chinese Abstracts (Reviews in Aquaculture, 2020)

Issue Information (Reviews in Aquaculture, 2020)

Immune response of pearl oysters to stress and diseases - Linda Adzigbli; Ruijuan Hao; Yu Jiao; Yuewen Deng; Xiaodong Du; Qingheng Wang; Ronglian Huang (Reviews in Aquaculture, 2020)
Pearl oysters are found in the marine ecosystem. Due to their frequent exposure to microbial pathogens and environmental perturbations, they have developed a multifaceted innate immune system with differentially expressed immune‐related genes in response to a range of stress via vast coordinated immune reactions, such as immune recognition, signal transduction, synthesis of antimicrobial peptides, encapsulation and phagocytosis of the circulating haemocytes. The species are farmed to produce pearls. With the increasing adoption of aquaculture techniques in pearl production, there is the need to understand their culture environment and their immune response mechanisms. Multi‐omic studies have documented responses to nuclei insertion operation, diseases and various environmental conditions in Pinctada fucata martensii (Dunker, 1880), Pinctada maxima (Jameson, 1901), Pinctada margaritifera and Pteria penguin (Roding, 1798). Among the various stressors, nuclei insertion operation has been identified as a prevailing factor modifying gene expression. Other factors include life stage, air exposure, temperature, salinity, metals and organic contaminants. This manuscript details the response mechanism of these pearl oysters to the various stressors.

Use of geographic information systems for aquaculture and recommendations for development of spatial tools - Lynne Falconer; Anne Lise Middelboe; Hanne Kaas; Lindsay G. Ross; Trevor C. Telfer (Reviews in Aquaculture, 2020)
There are many spatial issues associated with aquaculture which must be understood in order to support sustainable development and mitigate other potential issues. Geographic Information Systems (GIS) are used for investigation, analysis and modelling of aquaculture and there have been a considerable number of studies since the late 1980s. However, despite the range of applications, GIS is still often underutilized and stakeholders have requested more GIS‐based tools to support management and regulation of the sector. Consequently, there is a need to establish a knowledge base of existing applications and identify the challenges and opportunities to encourage development of tools that address user needs. This study presents a quantitative analysis of primary scientific literature, focusing on over 200 studies, to enable a comprehensive overview of the application of GIS and the trends associated with its use for aquaculture. Furthermore, there is a detailed assessment of the considerations when developing GIS‐based tools for aquaculture which culminates in five key recommendations regarding (i) usability of the tool; (ii) data requirements; (iii) accessibility to end user; (iv) capabilities and training requirements; and (v) longevity of the tool. These recommendations can guide future development and application of tools to support aquaculture planning and management and assess spatial issues relevant for the sector.

Effects of climate‐induced water temperature changes on the life history of brachyuran crabs - Mohamad N. Azra; Mohd Amran Aaqillah‐Amr; Mhd Ikhwanuddin; Hongyu Ma; Khor Waiho; Antonio Ostrensky; Camila Prestes dos Santos Tavares; Ambok Bolong Abol‐Munafi (Reviews in Aquaculture, 2020)
Water temperature is among the most important factors affecting reproduction and development of brachyuran crabs. The increase in mean global temperature resulting from climate change and atmospheric warming subjects all organisms to potential thermal stress. This paper reviews the effects of climate‐induce water temperature change on the thermal tolerance, thermal polygon and as expressed by changes in growth, development, thermal resistance, maturation, spawning and embryonic development throughout the brachyuran crab's lifespan. Survival and growth of brachyuran crabs, particularly during moulting, is temperature dependent. Thermal tolerance as depicted in thermal polygons varies among individuals depending on their acclimatization temperature and life stage, size and physiological condition. The mechanism of thermal tolerance and exact parameters of the thermal polygons of brachyuran crabs remain to be elucidated. Cooler water retards growth and delays maturity, causing crabs to begin maturation when they are at larger sizes. Crabs possess a set of behavioural, biochemical and physiological responses that enable them to compensate for temperature fluctuations, but these biological tools have limits.

Molecular and subcellular cryoinjury of fish spermatozoa and approaches to improve cryopreservation - Miaomiao Xin; Hamid Niksirat; Anna Shaliutina‐Kolešová; Mohammad Abdul Momin Siddique; Jan Sterba; Sergii Boryshpolets; Otomar Linhart (Reviews in Aquaculture, 2020)
The quality of frozen/thawed fish sperm is generally lower than that of fresh sperm. Extremely low temperatures are associated with damage to fish spermatozoon subcellular compartments and associated molecules such as DNA and proteins. Cryodamage can negatively affect DNA integrity, spermatozoon metabolism and motility, consequently impairing fertilization and embryo development. To preserve sperm efficiently, the addition of proteins including seminal plasma proteins, antioxidants, antifreeze proteins and antifreeze glycoproteins, and bovine serum albumin before and/or after freezing is suggested to minimize cryoinjury. An appropriate quantity of seminal plasma components in cryopreservation medium can prevent spermatozoon membrane damage by maintaining antioxidant enzymes and their proper distribution on the spermatozoon surface. Under storage conditions, the semen antioxidant system is ineffective in protecting spermatozoa from reactive oxygen species. The addition of antioxidants can provide protection for spermatozoa and reduce cryoinjuries during storage, but the effect of a given antioxidant is species‐specific. Antifreeze proteins and antifreeze glycoproteins can stabilize the cell membrane via interaction with phospholipid components and inhibit ice‐crystal growth to reduce damage related to osmotic stress and ice crystallization. However, they may exhibit a cytotoxic effect. This review summarizes the sources and characteristics of subcellular spermatozoon cryoinjury and discusses approaches to improve outcome of fish sperm cryopreservation.

A microbial sea of possibilities: current knowledge and prospects for an improved understanding of the fish microbiome - Thibault P.R.A. Legrand; James W. Wynne; Laura S. Weyrich; Andrew P.A. Oxley (Reviews in Aquaculture, 2020)
The mucosal surfaces of fish represent an important barrier that supports and regulates a diverse array of microbial assemblages and contributes to the overall health and fitness of the host. For farmed species, knowledge of how these host–microbial systems adapt and respond to various stressors is pivotal for managing health, nutrition and optimizing productivity in aquaculture. While our understanding of these communities and the factors that shape them now suggest that a diverse balanced microbiota is critical for healthy functioning in fish, the mechanisms behind these interactions are still poorly understood. Much of the existing research has focused on characterizing the taxonomic diversity of these assemblages in different fish species, across body surfaces (e.g. skin, gills and gastrointestinal tract), and in response to changing nutrition, health and environmental conditions. However, the specific functional contributions of these communities (or specific members) remain elusive, especially in farmed or diseased fish. Here, we review our current understanding of the microbiota in fish, their interplay and the likely functional involvement with the host. We also seek to address and identify gaps in knowledge and explore the future prospects for improving our understanding of these communities in aquaculture.

A critical overview of work‐related injury and illness in aquaculture workers from Brazil - Lissandra Souto Cavalli; Flavielle Blanco Marques; Andrew Watterson (Reviews in Aquaculture, 2020)
This review outlines the available data on aquaculture injuries and diseases in Brazil along with the deficiencies in some official data. The information was obtained from the official statistical sources of Brazil, and in part, complemented by some of the few scientific studies in the area. Between 2013 and 2017, the number of injuries and work diseases in Brazilian aquaculture totalled 873 cases. The total injury claims between 2015 and 2017 were 477 cases, of which 31 are related to requests for medical aid; 345 work leave cases for less than 15 days and 96 cases for more than 15 days; and 4 fatal injuries. However, official statistical data for aquaculture may be underreporting, limited and fragmented, and the real picture may be even larger. Nevertheless, the available data provide a means to prioritize both ways of improving such statistics and, more importantly, to identify tentatively those diseases and injuries that require urgent preventative action. Also, this paper proposes some measures that may help to achieve further progress on the working conditions to reduce potential dangers.

Intestinal alkaline phosphatase in the gastrointestinal tract of fish: biology, ontogeny, and environmental and nutritional modulation - Jean‐Paul Lallès (Reviews in Aquaculture, 2020)
Intestinal alkaline phosphatase is an evolutionarily conserved system that is pivotal in controlling gut and systemic inflammation. Its main properties, essentially discovered in terrestrial mammals, include regulation of enterocyte luminal surface pH and barrier function, detoxication of pro‐inflammatory microbial components, modulation of the gut microbiota and control of nutrient absorption (e.g. calcium, phosphorus, fatty acids). In return, enzymatic activity is modulated by gut microbes, cytokines, dietary nutrients and bioactive food components. Numerous data have been published on intestinal alkaline phosphatase in fish, especially in the contexts of biological development, nutrition and environment for sustainable aquaculture. This review provides a considerable account of basic and applied knowledge pertaining to this important protective enzyme in fish, and concludes that many features of intestinal alkaline phosphatase in fish fit those reported in terrestrial mammals, especially in its modulation by nutrients and bioactives in food. Notably, food intake is a strong inducer of intestinal alkaline phosphatase activity and is often not reported in publications, thus leading to some erroneous conclusions. Gaps in knowledge, e.g. on enzyme isoforms and molecular mechanisms involved in physiological and immunological (inflammatory) responses to biotic and abiotic factors, exist in fish and need to be considered. Future work should take into account food intake and both enzymatic activities as well as isoform expressions in order to further characterise in fish the important defensive functions of this highly conserved intestinal enzyme.

Nitrite implications and its management strategies in aquaculture: a review - Alexander Ciji; Mohammad Shahbaz Akhtar (Reviews in Aquaculture, 2020)
High nitrite levels are often encountered in intensive and recirculatory aquaculture systems but can also be found in natural waters under certain circumstances. Significant research advancement on nitrite and its implications in aquaculture sector has been made for last few decades, but emphasis on its management aspects has been given due consideration since recent past. Therefore, this review article not only aims to summarize the voluminous published reports on nitrite implications in fish but also recapitulates the research progress made on mitigation/management strategies. Nitrite exposure has been shown to adversely affect fish and shellfish growth, moulting, blood oxygen carrying capacity, water balance, osmoregulation, ionic homoeostasis and cause endocrine disruption. The nitric oxide produced from nitrite can inhibit several components of steroidogenic pathway leading to reduced reproductive performance. Different approaches and management strategies that have been evolved so far to address the nitrite‐associated stress have varying degrees of success. Adopting better nutritional approach like feeding antioxidant or nutraceutical fortified feeds along with effectively functioning biological filters is found to be helpful in reducing the deleterious effects of nitrite in cultured animals. This review paper, containing the plethora of information on nitrite and its management in one place, will definitely act as a ready reference for different stakeholders such as farmers, researchers and policymakers for sustainable development of aquaculture.

Review on integrated production of the brine shrimp Artemia in solar salt ponds - Gilbert Van Stappen; Liying Sui; Van Nguyen Hoa; Montakan Tamtin; Betty Nyonje; Renato de Medeiros Rocha; Patrick Sorgeloos; Gonzalo Gajardo (Reviews in Aquaculture, 2020)
The brine shrimp Artemia is a highly required, convenient and cost‐effective live food used in fish and shellfish larviculture. Its cysts, originating from a limited number of inland salt lakes, are traded worldwide. Over the past decades, Artemia pond production in solar saltworks, integrated with salt production, has emerged as an alternative to cope with possible cyst shortages and high prices on the international market and as a tool to fulfill local cyst and Artemia biomass demands associated with local and regional aquaculture developments. This article reviews the principles of Artemia pond production and how it is practiced in terms of general management. It also describes the distinctive features that have evolved in various countries, due to geographical, environmental and socio‐economic characteristics and the local aquaculture context. It highlights the lessons that may be learnt from previous successes and failures for new areas where the technique may be introduced. The principles of Artemia pond production are also discussed in the light of global and local Artemia biodiversity, as its protection is key to support the sustainability of the aquaculture industry. This review pioneers in bringing this information, much of which was restricted to grey literature until now, under the attention of the international scientific audience. Future research and development should focus on continued proper management to secure cyst production and to maximize cyst quantities. Moreover, using the information provided by the Artemia genome will allow as well to strive for improved cyst quality, by producing strains with specific market characteristics.

A review of fish identification methods applied on small fish - Marade Sandford; Gonzalo Castillo; Tien‐Chieh Hung (Reviews in Aquaculture, 2020)
Most of the research on marking of aquatic organisms has been done using large organisms since they tend to have better retention rates, their swimming behaviour is less affected by the size of the tag, they have less trauma due to injectable tags or from the injector itself and they are easier to handle and able to withstand the stress of tagging and recapture. The development of small tags has grown from a necessity to study smaller fish species, earlier life stages of fish and to study other small aquatic organisms. As an endangered species, delta smelt ( Hypomesus transpacificus ) are being intensively studied in the upper San Francisco Estuary ( CA , USA ). A crucial part of many of these studies is tracking delta smelt, which requires a distinctive mark on each individual or group of fish. Unfortunately, many of the experimental fish suffer inadvertent mortality, as delta smelt are very sensitive to environmental and handling stress. The purpose of this review was to synthesize the different tagging and marking studies on small fish and aquatic organisms and to evaluate the advantages and disadvantages of each method for applications on sensitive species such as delta smelt. This review suggests the most effective methods for tracking delta smelt are visible implant alphanumeric ( VIA ) tagging and adipose fin clips for subadult to adult fish and calcein marks for young life stages. Among these methods, only VIA tagging currently provides individual organism identification.

Mapping diversity of species in global aquaculture - Marc Metian; Max Troell; Villy Christensen; Jeroen Steenbeek; Simon Pouil (Reviews in Aquaculture, 2020)
Aquaculture is the world's most diverse farming practice in terms of number of species, farming methods and environments used. While various organizations and institutions have promoted species diversification, overall species diversity within the aquaculture industry is likely not promoted nor sufficiently well quantified. Using the most extensive dataset available (FAO‐statistics) and an approach based on the Shannon Diversity index, this paper provides a method for quantifying and mapping global aquaculture species diversity. Although preliminary analyses showed that a large part of the species forming production is still qualified as undetermined species (i.e. ‘not elsewhere included’); results indicate that usually high species diversity for a country is associated with a higher production but there are considerable differences between countries. Nine of the top 10 countries ranked highest by Shannon Diversity index in 2017 are from Asia with China producing the most diverse collection of species. Since species diversity is not the only level of diversity in production, other types of diversity are also briefly discussed. Diversifying aquatic farmed species can be of importance for long‐term performance and viability of the sector with respect to sustaining food production under (sometimes abrupt) changing conditions. This can be true both at the global and regional level. In contrast, selection and focus on only a limited number of species can lead to rapid improvements in terms of production (towards sustainability or not) and profitability. Therefore, benefits and shortcomings of diversity are discussed from both economical and social‐ecological perspectives that concurrently are shaping the expanding aquaculture industry.

Aquaculture of marine ornamental fish: overview of the production trends and the role of academia in research progress - Simon Pouil; Michael F. Tlusty; Andrew L. Rhyne; Marc Metian (Reviews in Aquaculture, 2020)
The marine ornamental fish trade is expanding and still largely relies on wild fish from tropical coral reef ecosystems. There are unknowns in the wild harvest so that the sustainability of marine ornamental fish trade can therefore be questioned with aquaculture being perceived as a responsible alternative for the procurement of these ornamental marine fish. However, there are still many technical constraints that hinder its development. These blocks require additional coordination with the outcome being an accelerated development of ornamental marine fish production. The main objective of this review was to better identify, understand and discuss the role and the impacts of academic research in the production of marine ornamental fish through qualitative and quantitative approaches. To do so, 222 selected scientific publications (including peer‐reviewed articles, conferences articles, thesis and reports) from the literature available to date were analysed and outcomes were framed in perspective of the total number of captive‐bred species. Results of the meta‐analyses indicate that academic research has led to significant advances in the breeding of some of the more difficult to breed species. While it has a leading role in conservation, its advance of techniques still lags behind private companies and hobbyists. Partnerships promoting synergistic activities between academic research institutes and the private sector (aquaculture farms and public aquariums) are important to optimize future ornamental marine fish production.

Biofloc technology: a review on the microbial interactions, operational parameters and implications to disease and health management of cultured aquatic animals - Akeem Babatunde Dauda (Reviews in Aquaculture, 2020)
Aquaculture is increasingly becoming more intensified leading to challenges to maintain optimal water quality conditions but also reducing effluent discharge to the environment. Therefore, the needs for the development of production systems that can ensure sustainable aquaculture production through minimizing the release of waste to the environment. Such technology should be easy to operate and available at a cheaper cost, both in installation and operations in order to suit the needs of both low and high‐income farmers. Biofloc technology is such a technology that can ensure sustainable aquaculture production, with low technical demands and it is available at a cheap cost. It is essentially a water quality management techniques, through manipulation of microbiota to convert the deleterious waste from aquaculture production to consumable body biomass and it has been established to have many other benefits asides from the intending water quality. This review discusses the developments of the biofloc technology, microbial interactions, important operational parameters and implication of the system to the disease and health management of cultured aquatic animals.

Sustainable aquaculture requires environmental‐friendly treatment strategies for fish diseases - Thora Lieke; Thomas Meinelt; Seyed Hossein Hoseinifar; Bo Pan; David L. Straus; Christian E. W. Steinberg (Reviews in Aquaculture, 2020)
Many classical therapeutants are going to be banned in Europe, and an urgent need for alternatives is emerging. This issue can be exemplified by one major parasitic disease in aquaculture and ornamental fish breeding: velvet disease. This disease, caused by dinoflagellates of the genera Amyloodinium and Piscinoodinium , is an important infection affecting cultured freshwater and marine ornamental and food fish, and consistently causes great financial loss to the associated industries. Therapeutants available contain copper, malachite green, or methylene blue, and which can be toxic to non‐target organisms in the surrounding environment. As a result, these chemicals are banned for use by the aquaculture industry in several countries, and a prohibition for commercial ornamental fishkeeping is likely to follow in most countries. Increasing development of resistance to therapeutants, and growing public awareness for animal welfare and environmental protection, have prompted research in the areas of alternative treatment options and immunostimulants. Hydrogen peroxide and peracetic acid are possible ‘green’ therapeutants which do not contribute residues to the environment. Natural feed supplements such as pre‐ and probiotics can increase animal welfare and prevent stress and/or infections. Humic substances are another promising, natural immunostimulants which will be considered in depth. The aim of this review is to provide an overview of risks and benefits of current treatment options and new approaches to replace harmful therapeutants and minimize the number of toxic residues discharged into the environment. Treatments will be discussed on various parasitic infections and focus, where available, on Amyloodinium and Piscinoodinium .

Fish type I and type II interferons: composition, receptor usage, production and function - Zhen Gan; Shan Nan Chen; Bei Huang; Jun Zou; Pin Nie (Reviews in Aquaculture, 2020)
Interferons ( IFN s) have been reported in vertebrates from fish to mammals. To date, two types of IFN s, i.e. type I and type II IFN s have been reported in a range of fish species in aquaculture. In fish, type I IFN s are clarified into group I and group II , with two cysteines and four cysteines, and further into subgroups a, d, e, h, and b, c, f, respectively. Group I IFN s appear to exist in all fish species, whereas group II IFN s are discovered only in certain species such as cyprinids, salmonids and perciform fish. It seems preferentially functional that group I IFN s signal through cytokine receptor family B ( CRFB ) 5 and CRFB 1, while group II IFN s through CRFB 5 and CRFB 2. But they all initiate a same signalling pathway for the expression of interferon induced genes. The information about the production and the function of type I IFN s in fish are further summarized in the review. Interestingly, two members of type II IFN s, IFN ‐γ and a unique member, IFN ‐γ related gene ( IFN ‐γrel) exist in fish, and IFN ‐γ and IFN ‐γrel can separately become homodimers for signalling through CRFB 13, CRFB 17, CRFB 6 and CRFB 17, respectively. In addition, the variation in the composition of type I and type II IFN s as well as in their receptors in some cyprinid and salmonid fish has also been reviewed. It is suggested that future perspectives for the research on type I and type II IFN s in fish are outlined from a comparative and evolutionary point of view.

Advances in nanotechnology for sustainable aquaculture and fisheries - Bakht Ramin Shah; Jan Mraz (Reviews in Aquaculture, 2020)
In recent years, aquaculture is considered a fastest‐blooming global food industry, playing a crucial role in fulfilling the increased demand for animal protein requirements. However, disease prevalence, chemical contamination, environmental degradation and ineffective feed utilization are the factors that drastically hinder the outcome of this sector in aiding to achieve global food security. In this regard, new avenues have been paved in science and technology to cope with these challenges in aquaculture. Among these, nanotechnology has emerged a tremendous potential to improve aquaculture with novel nanotools. This review critically analyses the advances in the application of nanoparticles and emulsion‐based systems to fish disease prevention, water purification and delivery of nutrients. On the other hand, as the use of antibiotics and other chemical antimicrobial agents, synthetic compounds as growth enhancers not only leads to aquaculture pollution but also consumer's reluctance. Therefore, the importance of ecofriendly, non‐toxic natural strategies to promote sustainable aquaculture has also been highlighted.

Brazilian legal framework on shellfish safety and its effects on the growth of shellfish farming and commerce - Andrea Lafisca; Eliana de Fátima Marques de Mesquita; Olney Vieira‐da‐Motta (Reviews in Aquaculture, 2020)
Shellfish are among the most at‐risk foods of the occidental culture, requiring special control along all the production chain to provide safe products to the population. Codex Alimentarius regulations offer orientations to the control and guarantee of shellfish safety, but the practical application of their indications shall be hampered at the local level by several elements: political, logistic and geographic, as examples. In this article, we provide a comprehensive review of the Brazilian legislative framework on shellfish safety in comparison to those proposed by other trading blocs, mainly the European Community and the USA. Our analysis points out how the simple application of international guidelines on shellfish safety designed for non‐tropical areas, the lack of political interest, and scientific orientation, and the concentration of reference laboratories in the extreme south of Brazil, hamper the development of safe and legal shellfish farming and commerce in the rest of the country.

A review of alternative pond harvesting schedules for male and female redclaw crayfish Cherax quadricarinatus , reared in intensive monosex commercial conditions: a stochastic bioeconomic approach - Alfredo Hernández‐Llamas; Lavinia Núñez‐Amao; José Naranjo‐Páramo; Mayra Vargas‐Mendieta; Humberto Villarreal (Reviews in Aquaculture, 2020)
We use a bioeconomic model to analyse two alternative harvesting schedules for male and female redclaw: simultaneous (same day) harvests of ponds for each sex and harvesting ponds independently for each sex (different days). The results show that, for simultaneous harvests, best results are obtained after 120 days of cultivation yielding, with 95% confidence, a mean net revenue (NR) of 26,820 USD$ ha −1 and mean benefit–cost ratio (B/C) of 3.08. For independent harvests, best results are obtained by harvesting males after 109 (NR) and 97 (B/C) days, and females after 120 (NR) and 107 (B/C) days. At these optimum harvesting times, with 95 % confidence, expected mean NR for males was 30560 USD$ ha −1 and mean B/C was 3.56; while for females NR was 23,620 USD$ ha −1 and B/C was 2.92. Results show that using independent harvests maximizes benefits. Better economic performance and statistical confidence were observed for males. The dynamics of commercial grade categories is the most important factor influencing the stochastic variability of NR, while the cost of production of pre‐adults is negligible, indicating the reliability of the cultivation technology for the nursery stage. Bioeconomic modelling provides an objective framework for farming practices evaluation and avenues for improvement. Monosex redclaw crayfish culture is environmentally sustainable, with a consistent production technology that is economically viable. With increasing world demand, it should be considered a strong candidate species for diversification.

Application of Spirulina in aquaculture: a review on wastewater treatment and fish growth - Feng Zhang; Yu Bon Man; Wing Yin Mo; Ming Hung Wong (Reviews in Aquaculture, 2020)
There is an urgent need to find alternatives to fish meal and fish oil in compound feeds due to their rapidly rising prices and the demand for sustainable fisheries. Spirulina, a filamentous blue‐green microalga, is an excellent source of plant protein and could replace expensive animal‐derived proteins in fish feed. Studies have evaluated the use of spirulina as a fish meal for different fish species. This paper reviews research on the effects of spirulina on the growth performance of various fish species. It is apparent that spirulina can be a highly important component of the diet of fish; it has a number of benefits, such as promoting the growth of tilapia ( Oreochromis niloticus ) and carp ( Labeo rohita ), improving the reproductive performance of yellow tail cichlid ( Pseudotropheus acei ) and enhancing the immune response of rainbow trout ( Oncorhynchus mykiss ). Recent studies have shown that spirulina can be used for treating wastewater, including effluent from fish culture activities, as it can efficiently metabolize the nutrients and remove the heavy metals contained in aquaculture effluent. Fish aquaculture could apply an integrated strategy of simultaneously treating aquaculture effluent while producing spirulina biomass to supplement fish diets.

Risk assessment of the use of alternative animal and plant raw material resources in aquaculture feeds - Brett D. Glencross; Johanna Baily; Marc H.G. Berntssen; Ronald Hardy; Simon MacKenzie; Douglas R. Tocher (Reviews in Aquaculture, 2020)
A wide range of raw materials are now used routinely in aquaculture feeds throughout the world, primarily to supply protein and energy in the form of lipid from edible oils. Protein meals and oils used can generally be divided into those of plant or animal origin and many have considerable potential to supply the required dietary nutrients required by aquaculture species. However, the use of any raw material introduces a suite of risks that need to be considered to enable the production of safe, sustainable and functional feeds to underpin this sector. A lack of understanding of some of those risks can result in failure of dietary specifications being met and/or negative nutritional elements being introduced (e.g. antinutritional factors). Importantly, it is this feed that when fed to food‐producing animals is such an important element of food safety, and as such any undesirable aspects relating to feed production can also have a negative impact on the rest of the food chain. However, there is some disparity internationally among raw materials that are used and the perceptions surrounding the risk of their use. It is the scientific assessment of these risks that is the basis of this review.

A systematic literature review of the major factors causing yield gap by affecting growth, feed conversion ratio and survival in Nile tilapia ( Oreochromis niloticus ) - Samuel Bekele Mengistu; Han A. Mulder; John A. H. Benzie; Hans Komen (Reviews in Aquaculture, 2020)
Productivity among small‐ and medium‐scale tilapia farms varies considerably. The difference between the best performers and lower ones (yield gap), is affected by differences in growth rate and feed conversion ratio ( FCR ). FCR at the farm level is strongly influenced by survival of fish. In this study a systematic literature review of two databases ( ASFA and CAB ‐Abstracts) identified 1973 potentially relevant articles. Data from 32 articles that met the inclusion criteria were analysed using linear mixed models for the most important factors with significant contributions to growth [investigated through analysis of the thermal growth coefficient ( TGC )], survival and FCR of Nile tilapia. Increasing crude protein ( CP ), dissolved oxygen ( DO ) and pH significantly decreased FCR and increased TGC . Increasing stocking weight ( SW ) significantly improved both FCR and survival. Temperature had the largest effect on FCR followed by DO , pH and CP . DO had the largest effect on TGC followed by CP and pH . This study confirms that the optimal rearing temperature for Nile tilapia is between 27 and 32°C. Improving management to optimize DO (> 5 mg/L), stocking density (3–5 fish/m 2 ), SW (> 10 g) and CP (25 − 30%) will improve performance and survival in small‐ and medium‐scale tilapia farming. However, it is hard to influence temperature in ponds and cages while DO is largely influenced by aeration. Since many small‐ and medium‐sized farms do not have aeration, these major tilapia farming systems could benefit from genetically improved strains selected for resilience to highly fluctuating diurnal temperature and DO levels.

Infrastructure, management and energy efficiency in a hypothetical semi‐intensive shrimp model farm in Brazil: a systematic review and meta‐analysis - Nathieli Cozer; Giorgi Dal Pont; Aline Horodesky; Antonio Ostrensky (Reviews in Aquaculture, 2020)
The goal of this study was to characterize the main operational processes adopted by a shrimp aquaculture pond system in Brazil and to account the flows of energy use. The characterization was carried out via application of the Preferred Reporting Items for Systematic Reviews and Meta‐analyses (PRIMA) methodology. The accounting of the energy flows was made through the quantification of the energy coming from economically required resources. Based on the data and characteristics identified in Brazilian shrimp farms, a hypothetical farm consisting of four nursery tanks, nine ponds, feed, fertilizer and general deposits, a refectory, restrooms and dressing rooms, garage, and main and secondary access roads. In this hypothetical shrimp farm, the water pumping was performed by a 20 hp pump, and aeration was performed via 4 hp paddle‐type aerators. A biphasic operating system and a semi‐intensive production regime were adopted, with a initial stocking density of 43 shrimp m −2 and harvest occurring when the shrimp reached an average weight of 12 g. The cultivation cycle lasted 90 days and include the pond preparation and curing period. The final yield was estimated to be 3500 kg ha −1 . The total energy cost was calculated as 835.597 MJ. The most energy inputs were feed, fuels and lubricants and electricity. Shrimp production in ponds is a very intensive activity relative to the energy demand and that increasing energy efficiency is one of the essential conditions for the truly sustainable production of long‐term Brazilian shrimp farming not only for environmental but also mainly for economic reasons.

Understanding the development of intermuscular bones in teleost: status and future directions for aquaculture - Chun‐Hong Nie; Alexandre W. S. Hilsdorf; Shi‐Ming Wan; Ze‐Xia Gao (Reviews in Aquaculture, 2020)
As one of the most sustainable protein sources for humans, aquaculture is the fastest growing food production sector in agriculture. According to the recent FAO estimate, there are 21 principal aquaculture fish species around the worldwide. Among these cultured species, almost half of them belong to Cypriniformes, the species from which all have a certain number of intermuscular bones ( IB s). IB s are small spicule‐like bones existing in the muscle fillet, which are existed only in lower teleost and of course have a negative effect on fish quality and aquatic product processing. Many studies have been focusing on IB s number, morphology, and more and more become focusing on its development molecular mechanism. In the review, we summarized the recent progress and discussed with following directions: (i) Controversial on the origin of IB s, ossified from tendons or ligaments? (ii) IB s counts and morphology revealed big variation among different species; (iii) Ossification patterns of IB s might be related with different swimming modes among the teleost fish, and its development belongs to intramembranous ossification without cartilaginous phase; (iv) Transcriptome/micro RNA (mi RNA )/proteomics and gene functional analysis had been used to investigate the molecular mechanism of IB s development and some genes showed certain regulatory roles during IB s’ development; (v) The reports showed that some breeding technologies could make a certain effect on IB s counts in fish species, but there are rare reports with success on deleting or significantly reducing IB s counts. Meanwhile, we also discuss the challenges and future directions of reducing or even deleting IB s in aquaculture.

Evaluating antimicrobial resistance in the global shrimp industry - Kelly Thornber; David Verner‐Jeffreys; Steve Hinchliffe; Muhammad Meezanur Rahman; David Bass; Charles R. Tyler (Reviews in Aquaculture, 2020)
Antimicrobial resistance ( AMR ) is a growing threat to global public health, and the overuse of antibiotics in animals has been identified as a major risk factor. With high levels of international trade and direct connectivity to the aquatic environment, shrimp aquaculture may play a role in global AMR dissemination. The vast majority of shrimp production occurs in low‐ and middle‐income countries, where antibiotic quality and usage is widely unregulated, and where the integration of aquaculture with family livelihoods offers many opportunities for human, animal and environmental bacteria to come into close contact. Furthermore, in shrimp growing areas, untreated waste is often directly eliminated into local water sources. These risks are very different to many other major internationally‐traded aquaculture commodities, such as salmon, which is produced in higher income countries where there are greater levels of regulation and well‐established management practices. Assessing the true scale of the risk of AMR dissemination in the shrimp industry is a considerable challenge, not least because obtaining reliable data on antibiotic usage is very difficult. Combating the risks associated with AMR dissemination is also challenging due to the increasing trend towards intensification and its associated disease burden, and because many farmers currently have no alternatives to antibiotics for preventing crop failure. In this review, we critically assess the potential risks the shrimp industry poses to AMR dissemination. We also discuss some of the possible risk mitigation strategies that could be considered by the shrimp industry as it strives for a more sustainable future in production.

Antibiotic use in aquaculture, policies and regulation, health and environmental risks: a review of the top 15 major producers - Ronald Lulijwa; Emmanuel Joseph Rupia; Andrea C. Alfaro (Reviews in Aquaculture, 2020)
This review focuses on the current status of antibiotics use, effects on animal health and the environment, existing policies and regulatory mechanisms in the top 15 producing countries. Fifty papers were reviewed and represented the bulk of literature worldwide. We observed that 67 antibiotic compounds were used in 11 of the 15 countries between 2008 and 2018. Among these countries, 73% applied oxytetracycline, sulphadiazine and florfenicol. On average, countries used 15 antibiotics and the top users included Vietnam (39), China (33) and Bangladesh (21). On environmental and health risks, the review revealed sufficient evidence that directly links antibiotics use to food safety, occupational health hazards and antimicrobial resistance. Environmental risks included residue accumulation, aquatic biodiversity toxicity, microbial community selection for antibiotic resistance and the emergence of multi‐antibacterial resistant strains. Regarding policies, major players were the European Commission, the Food and Drug Administration, European Medicines Agency, Norwegian Veterinary Institute, the Norwegian Food Safety Authority, Codex and government ministries. In particular, the Norwegian Food Safety Authority and Norwegian Veterinary Institute demonstrated the most outstanding regulation mechanisms of antibiotics use in aquaculture that needs to be emulated. The future of aquaculture lies in guaranteeing the supply of safe aquatic products to the growing consumer market. Thus, international coordination of the policy and regulatory environment is needed, while increased investment in research for alternative aquatic health management strategies is essential. Future technologies should focus on the reduction of antibiotics use to safeguard the environment and ensure safety of consumers, feed industry and aquaculture workers.

Evaluation of large‐scale marking methods in farmed salmonids for tracing purposes: Impact on fish welfare - Ingebrigt Uglem; Tore S. Kristiansen; Cecilie M. Mejdell; Dean Basic; Stein Mortensen (Reviews in Aquaculture, 2020)
Escaped farmed Atlantic salmon ( Salmo salar ) is considered a threat to wild salmon. In order to take action to reduce the impact of escapees, methods to distinguish escapees from wild fish and to trace them back to their origin are in demand. This paper gives an overview of available methods and discusses the impact on fish welfare, both in the short‐ and long‐term. Adipose fin clipping, freeze branding, different external and internal tags, as well as natural and chemical marks are considered. All marking procedures that involve handling of fish have an impact on fish welfare. Spraying with pigments and most externally attached tags significantly reduce the welfare, both on short‐term and long‐term perspectives. Although the use of natural or chemical marks, like exposure to stable isotopes via egg immersion or vaccination, involves no or no extra handling, subsequent analysis may require killing the fish after catch. Large‐scale marking with implanted or external tags could represent higher risks of human errors and reduced fish welfare, as opposed to small‐scale marking. In general, the knowledge about effects of marking on fish welfare is limited for most of the available methods, in particular regarding other effects than mortality and growth reductions.

Causative agent, diagnosis and management of white spot disease in shrimp: A review - Bipul K. Dey; Girsha H. Dugassa; Sheban M. Hinzano; Peter Bossier (Reviews in Aquaculture, 2020)
White spot syndrome virus ( WSSV ) is the pathogen behind white spot disease ( WSD ) in shrimp and many other crustaceans. It is a highly contagious virus capable of causing total mortality in 3–10 days of outbreak in normal culture conditions. Since the first report of occurrence in China and Taiwan between 1991 and 1992, WSD outbreak caused tremendous losses at farm level throughout the world. Most of the published reviews on WSSV emphasize advanced genetic studies and biosecurity measures in terms of disease management. Recently, some new technologies such as greenhouse, polyculture, biofloc and minimal water exchange have been proposed for WSD management, which is the trigger for this review. However, further research is needed on those new technologies enhancing their efficient application.

Application of lipidomics in bivalve aquaculture, a review - Vincenzo A. Laudicella; Phillip D. Whitfield; Stefano Carboni; Mary K. Doherty; Adam D. Hughes (Reviews in Aquaculture, 2020)
Bivalve production is a relevant aquaculture activity in Europe; however, it is not developing with same extents of other aquaculture sectors due to causes connected with regulation stringency, labour cost, space availability, habitat loss as well as variability in recruitment events, climate change and diseases. Understanding the physiology and nutritional requirements of bivalves during aquaculture activities might result beneficial to fuel up the development of the sector. Lipids are important molecules as they are relevant components of cellular membranes acting in several physiological processes like reproduction, growth, immunological responses and energy reserve. Nevertheless, lipid diversity is still poorly understood despite the research efforts of the last decades. Technological advancements provide tools to unveil such diversity. Lipidomics, a branch of metabolomics, is the science targeting the lipidome (e.g. the totality of biological lipids in an organism). In this review, lipidomics, and its related concepts, are discussed providing an overview of recent lipidomics studies on bivalves. Lipidomics could result in several advantages if compared with traditional lipid profiling techniques; however, aims and scopes of future lipidomics studies should be expanded. Here, possible future applications of lipidomics in the context of bivalve production are presented and discussed. Unveiling the lipidome of marine bivalves could aid disclosing important information regarding nutrition, biology, physiology and epidemiology on bivalves. This knowledge, once applied, has the potential to improve bivalve production and the resilience of the sector to environmental changes.

Application of fermentation strategy in aquafeed for sustainable aquaculture - Mahmoud A.O. Dawood; Shunsuke Koshio (Reviews in Aquaculture, 2020)
Because of its high nutritional value, palatability and increased digestibility, fishy meal is widely used as an animal protein source in the aquafeed industry. However, the resource shortages and rising prices seriously restrict the use of fish meal (FM) in aquaculture. In this light, much efforts have been conducted to seek the sustainable supplies of protein sources to substitute FM. Due to their relatively low protein content and palatability, the presence of anti‐nutritional factors (ANFs) and unbalanced amino acid profiles, the plant protein sources have been limited in aquafeed, whereas the animal protein sources can replace FM in aquafeed due to their high protein content, total digestible dry matter and lack of ANFs. The fermentation process was recognized for its role in improving the nutritional quality of animal and plant protein sources. The protein sources can be treated with appropriate microorganisms to preserve its nutrients and finally incorporated into aquafeed, which would reduce feed costs and environmental pollution. Fermented meals showed better nutrient efficiency and could improve the nutritional value of aquafeed. This review was intended to present more updated information about the application of fermented ingredients in aquafeed industry. Based on the data collected, this review will contribute to further research into the production of fermented feed as a functional feed for sustainable aquaculture.

Exploring the potential for marine aquaculture to contribute to ecosystem services - Rebecca R. Gentry; Heidi K. Alleway; Melanie J. Bishop; Chris L. Gillies; Tiffany Waters; Robert Jones (Reviews in Aquaculture, 2020)
Marine aquaculture is growing quickly and has substantial effects on people and the environment. Existing research has demonstrated that marine aquaculture can contribute to ecosystem service provisioning that extends beyond production of a resource; however, the extent and significance of these goods and services are not well understood. Here we review existing knowledge of ecosystem service provision by marine aquaculture by systematically examining 129 peer reviewed papers that describe the provision of nine distinct ecosystem services by operational or experimental marine aquaculture farms. We quantify service provision and classify services by type and by farm characteristics. We show that while certain services, such as nutrient absorption by kelp aquaculture, are well understood and have been documented across multiple species, scales and environments, the evidence for other services, such as the cultural service of tourism, is currently minimal. Importantly, we identify ecosystem services associated with a diversity of farm types (including fish, bivalve, algae and polyculture farms) but find that certain services were most often delivered by specific farm types (e.g. habitat services were most often associated with fish farms). Incorporating acknowledgement of ecosystem services into farm design and planning has the potential to improve environmental performance and sustainable management of aquaculture. However, outstanding questions, including how spatial expansion of marine aquaculture will affect the provisioning of these services, are important challenges facing sustainable development.

Review: Molecular mechanisms of sex differentiation in sturgeons - Magdalena Fajkowska; Teresa Ostaszewska; Małgorzata Rzepkowska (Reviews in Aquaculture, 2020)
Sex determination is a complex process, especially in fish where multiple models of sex determination can be identified. The fate of differentiating gonads may depend on species genetics, environmental or behavioural factors. In the case of the sturgeon, sex determination is most likely of genetic origin and is characterized by a ZW female heterogametic system. However, molecular mechanisms of sex development and differentiation in sturgeons are poorly understood. Due to the lack of sexual dimorphism and a long period of maturation combined with invaluable caviar obtained from sturgeons, plenty of research revolving around discovering master sex‐determining gene has been done. Yet, despite numerous studies utilizing multiple approaches and techniques to find key genes involved in sex differentiation, no master sex‐determining genes were identified in sturgeons. Nevertheless, the latest research provided a great deal of data regarding the expression of genes commonly related with sex development and differentiation in vertebrates. Several of these genes were found to be connected with the same processes in sturgeons. This review attempts to summarize research into the expression of genes involved in sex differentiation and development in sturgeons.

Aquaculture and sensometrics: the need to evaluate sensory attributes and the consumers’ preferences - Juan B. Calanche; José A. Beltrán; Adrián J. Hernández Arias (Reviews in Aquaculture, 2020)
Aquaculture represents a vital food production industry that contributes to the global economy and fish supplies. Several studies had suggested that changes in the production process, especially those related to nutritional and feeding interventions may have an impact on the final quality of farmed animal food products including those from aquaculture. An integrated approach is needed to close the gap between consumers’ response and aquaculture products which sensorial quality aspects could be altered by the inclusion of new alternative protein and lipid sources in aquafeed. Applied research efforts in aquaculture should recognize the significance of consumers’ behaviour and preferences with the aim of making this industry economically sustainable. Until now, sensory research in aquaculture has been developed in different ways depending on the commercial interest of the species implicated. The sensory analyses generally used in aquaculture were identified in four main application research areas: nutrition and feeding, production aspects, quality product and marketing topics. Applied aquaculture research for the continued growth of this industry needs to be complemented with the findings and possibilities offered by sensometrics. This paper aims to provide an overview of sensory analysis used in aquaculture as an activity that supplies products to the market. The main opportunity that sensometrics could offer to the aquaculture industry is to apply an accurate approach that takes into account the consumer.

Recent advances of nucleotide nutrition research in aquaculture: a review - Md. Sakhawat Hossain; Shunsuke Koshio; Patrick Kestemont (Reviews in Aquaculture, 2020)
Although nucleotides ( NT ) have long been implicated as feed attractants in both vertebrate and invertebrate species, research into potential growth and health benefits of dietary NT in aquaculture species has just been implemented in early 2000s. To date, research pertaining to NT supplementation in aquafeed as functional nutrients has shown rather consistent and encouraging, beneficial results in fish and shrimp health management. Dietary NT serve a marked role to enhance growth in early stages of development, improve reproductive performances of brood fish, enhance larval quality, increase stress and disease resistance, modulate immune functions and improve intestinal morphology and gut microbiota of fish and shrimp. NT have also been used as functional supplement in alternative protein based diet, where NT was found as an effective supplement to increase the efficiency of utilizing alternative proteins. However, still there are numerous gaps in existing knowledge about exogenous NT administration to fish and shrimp including various aspects of digestion, absorption, metabolism, administration duration and age/size‐related responses. Adoption of different molecular technologies, like proteome modification and study of several gene expression pattern related to growth, immunity, gut health and stress resistance in details are important for exploring the underlying mechanisms of NT functions in improved growth and health performances of fish and shrimp. Efforts are also needed on production technologies to reduce the NT cost. Moreover, extensive research information is also required regarding the use of NT in alternative protein and lipid based diet to develop cost‐effective, ecofriendly functional aquafeed in near future.

Antibacterial proteins and peptides as potential treatment in aquaculture: current status and perspectives on delivery - Lina Angélica Zermeño‐Cervantes; Bárbara González‐Acosta; Sergio Francisco Martínez‐Díaz; César Salvador Cardona‐Félix (Reviews in Aquaculture, 2020)
Although aquaculture is a growing productive sector, economic losses because of infectious diseases and public health concern of what antibiotic resistance represents have become factors that limit its development. Thus, the control of infectious diseases through antibacterial alternatives is a field of intense research. In this sense, antimicrobial proteins and peptides might represent a safe and effective alternative because their site of action is on microbial components; they are biodegradable; their diversity in terms of mechanisms of action is broad; and some of them can be highly specific. Because this antibacterial alternative is still in research, this review provides a critical analysis of the challenges and opportunities of protein drugs for the treatment of bacterial diseases in the field of aquaculture health; contextualizes the different types of antibacterial protein and peptides, their mechanisms of action, potential sources, as well as the state of the art on assessment of antibacterial proteins and peptides in bioassays with aquatic organisms; and discusses the challenges proteinaceous drugs face regarding their stability for oral delivery and the perspectives for their administration in aquaculture.

How do freshwater fish sperm find the egg? The physicochemical factors guiding the gamete encounters of externally fertilizing freshwater fish - Vitaliy Kholodnyy; Hermes Gadêlha; Jacky Cosson; Sergii Boryshpolets (Reviews in Aquaculture, 2020)
The lifespan of spermatozoa from externally fertilizing freshwater fish ranges from a few seconds to several minutes, depending on the species. External factors, such as temperature, background flows and ion composition, play an important role in fertilization success. Specific mechanisms guiding spermatozoa appear to be essential to maximize the sperm–egg encounter under these strenuous conditions. Although some existing data support the hypothesis that both the ovarian fluid and the eggs may release chemoattractants that significantly affect spermatozoa behaviour and the fertilization outcome, this hypothesis is still open to debate, as the existence of freshwater fish spermatozoa chemotaxis has yet to be demonstrated; in addition, specific mechanisms supporting spermatozoa guidance and gamete selection have not been elucidated. Is the natural selection of gametes determined by a combination of different physicochemical phenomena? Alternatively, is the natural selection of species‐specific gametes biased towards the species‐specific guidance mechanisms of their natural landscape? These questions have received more attention as new studies have revealed potential, distinct guidance mechanisms in freshwater fish reproduction. In this review, we discuss the empirical studies supporting different hypotheses about freshwater fish gamete guidance and highlight the synergistic combination of experiments and biomathematical modelling to explore these questions. Finally, we discuss the challenges in understanding the mechanisms behind sperm guidance in freshwater fish species, and we suppose that knowledge about the mechanisms that underlie spermatozoa selection and guidance in freshwater fish species may elucidate the impact of the traditional aquaculture practice of artificial fertilization on progeny quality and species sustainability.

From Vagrant to Resident: occurrence, residency and births of leopard seals ( Hydrurga leptonyx ) in New Zealand waters - Krista Hupman; Ingrid N. Visser; Jim Fyfe; Martin Cawthorn; Giverny Forbes; Alexander A. Grabham; Rick Bout; Brittany Mathias; Ella Benninghaus; Kimberly Matucci; Tracy Cooper; London Fletcher; et al. (New Zealand Journal of Marine and Freshwater Research, 2020)
In contrast to previous reports that leopard seals ( Hydrurga leptonyx ) are rare vagrants to New Zealand, we show that this species is a regular member of the marine fauna of this region. We present a first analysis from the New Zealand Leopard Seal Database – an extensive collation of 2,711 records of leopard seals within New Zealand between 1200 and 2018. Of these records, 51.2% ( n = 1,408) were photographic. Leopard seal sightings have increased over time and been reported in all seasons and regions of New Zealand. Sightings are predominantly of adult individuals of good or excellent body condition, which differs to previous hypotheses suggesting that leopard seals visiting New Zealand shores are primarily juvenile animals in poor health condition. A total of 176 unique individuals have been identified in the New Zealand Leopard Seal Catalogue between 2014 and 2018 and preliminary results indicate that numbers per annum have continued to increase over time. Three leopard seal births and a number of juvenile animals (34% of the NZ records) have been documented. Considering the information presented here and the current definitions in the New Zealand Threat Classification System, the threat status of leopard seals within New Zealand waters should be reclassified from Vagrant to Resident.

Comparing traditional and modern methods of kākahi translocation: implications for ecological restoration - Amber Julie McEwan; Aaria Ripeka Dobson‐Waitere; Jeffrey S. Shima (New Zealand Journal of Marine and Freshwater Research, 2020)
Handling methods are an important determinant of translocation success. In Aotearoa/New Zealand, tangata whenua traditionally used insulated kete to translocate aquatic animals to new environments as part of ahumoana tawhito (ancient aquaculture). In this study we investigated the influence of three transport methods (traditional [flax kete], modern [bucket], and a hybrid of the two [bucket with flax support structures]) on the short‐term performance (burrowing speed) of kākahi (freshwater mussels). We also tested whether assisted release (planting kākahi in the substrate) resulted in enhanced burrowing speeds. Kākahi that were transported using the traditional method were slower to begin probing the substrate, but there was no difference in overall burrowing speed. We also found that assisted release resulted in faster burrowing speeds. We conclude that handling and release procedures can influence the short‐term performance of translocated kākahi, and we recommend procedures for future translocation projects, including transporting animals in immersion vessels where practical, and planting them at the release site

A New Zealand demersal fish classification using Gradient Forest models - Fabrice Stephenson; John R. Leathwick; Malcolm P. Francis; Carolyn J. Lundquist (New Zealand Journal of Marine and Freshwater Research, 2020)
Spatial classifications of the environment have previously been used to characterise biodiversity and to facilitate management planning at large spatial scales. Such classifications are more likely to be adopted if they can demonstrate integration of real patterns in habitats or biotic assemblages, in addition to environment. A previous classification used Gradient Forest analysis to derive 30 classes based on demersal fish assemblage patterns and environmental gradients. Here we provide a detailed description of the similarities and differences in the environment and fish assemblages of classes resulting from an updated classification using the same methodology. Environmental differences were associated with varying levels of differences in the distributions of fish species. At broad spatial scales, assemblages are differentiated primarily according to oceanographic conditions such as temperature and depth; at finer scales, patterns in species assemblages are more closely associated with more localised environmental conditions such as productivity, sea‐surface temperature gradients and tidal currents. The 30‐group classification allows complex biodiversity information to be summarised in ways accessible to stakeholder and environmental managers. Given the hierarchical nature of the classification, there is considerable scope to use a larger number of groups for applications at regional to local scales.

New Zealand estuary benthic health indicators summarised nationally and by estuary type - Anna Berthelsen; Javier Atalah; Dana Clark; Eric Goodwin; Jim Sinner; Murray Patterson (New Zealand Journal of Marine and Freshwater Research, 2020)
Ecological data are often collected at small geographic scales. However, analysing data collectively over wider scales can reveal results and patterns not shown in the smaller‐scale data. We summarised data for intertidal benthic ecological (physico‐chemical and biological) health indicators from New Zealand estuaries and compared the results against thresholds above which ecological impacts are expected to occur. Values for the sediment physico‐chemical indicators mud and nutrients (nitrogen and phosphorus collectively) were above thresholds for at least 50% and at 31% of sites measured respectively. Sediment organic content and metal concentrations were generally low, with only maximum values exceeding the thresholds. Scores for biological indicators were within (or better than) the moderate health category for either at least 50%, or at least 75%, of sites. When compared across estuary types (based on a geomorphic classification system) we found statistically significant differences for thirteen of the sixteen indicators. Differences (among mean values) for highly significant results were relatively large compared to the range of values observed nationally for those indicators. However, the differences, except those for mud, were smaller than their respective ecological health threshold values. Our summary provides a reference for future comparisons of estuary indicators nationally and across estuary types.

Dividing the algal soup: is there niche separation between native bivalves ( Echyridella menziesii ) and non‐native Daphnia pulex in New Zealand? - Anita A. C. Pearson; Ian C. Duggan (New Zealand Journal of Marine and Freshwater Research, 2020)
New Zealand's native freshwater mussels (kākahi, kāeo) are considered to be in decline, yet the mechanisms driving this are unclear. The widespread establishment of highly efficient filter‐feeding, non‐native Daphnia in New Zealand lakes may have led to competition for algae with kākahi. We conducted a controlled laboratory experiment to determine whether differences exist in algal resources utilised by kākahi and North American Daphnia pulex . Echyridella menziesii (adults and juveniles) and D . pulex were exposed to mixed algal samples for three hours to determine whether similar algal resources were removed by the grazers. Relative to controls, both adult and juvenile E. menziesii removed a broad range of algal taxa including diatoms, green algae and filamentous species, ranging in size from 33.6 to 348.0 μm. High densities of D . pulex were unable to cause depletion of these same algae species. Our results suggest niche overlap is limited between the two grazers; E . menziesii utilises larger particles than D . pulex .

Water temperature interacts with the insecticide imidacloprid to alter acute lethal and sublethal toxicity to mayfly larvae - Samuel J. Macaulay; David B. Buchwalter; Christoph D. Matthaei (New Zealand Journal of Marine and Freshwater Research, 2020)
Increased temperatures and exposure to agricultural insecticides are increasingly threatening freshwater ecosystems worldwide. However, their combined effects are still poorly understood. We investigated the individual and interactive effects of water temperature and imidacloprid, the most widely used neonicotinoid insecticide, on larvae of two New Zealand mayflies, Deleatidium spp. and Coloburiscus humeralis . Ninety‐six‐hour bioassays with imidacloprid were performed at 9, 12, 15, 18, 21 and 24°C, in a full‐factorial design. Mayfly survivorship and sub‐lethal responses of impairment and moulting were recorded. We documented synergistically increased mayfly mortality and immobility with exposure to imidacloprid at higher temperatures, implying temperature‐enhanced toxicity of imidacloprid. Survivorship of both mayflies was synergistically reduced by the combination of imidacloprid exposure and increasing temperatures. The same interaction also affected mobility of C. humeralis and moulting frequency of Deleatidium . Our findings suggest that developing a more thorough understanding of temperature‐contaminant interactions may be important to allow better protection of aquatic ecosystems.

Reexamination of the spawning migration of Anguilla dieffenbachii in relation to water temperature and the lunar cycle - Shun Watanabe; Takatoshi Higuchi; Masaharu Noshiro; Ryotaro Manabe; Michael J. Miller; Donald J. Jellyman; Katsumi Tsukamoto (New Zealand Journal of Marine and Freshwater Research, 2020)
The oceanic spawning migration of female Anguilla dieffenbachii eels was previously studied using pop‐up satellite transmitting tags (PSAT). The swimming depths and experienced‐temperature data of 3 eels released in May 2006 were re‐examined in relation to water temperature data, and also lunar cycle and regional hydrography as these latter aspects were not considered in the original study. Eel 2 and Eel 3 initially experienced lower water temperature above 600 m, suggesting they remained south of the subtropical‐convergence front longer than Eel 1. Their experienced nighttime minimum depths showed linear relationships with the lunar cycle, because they swam shallower during new moon than during full moon. The eels experienced narrow deep‐day temperature ranges at a wide range of depths compared to experiencing narrow shallow‐night depth ranges where temperatures varied more widely, indicating that several different factors determine their day and night depth ranges.

Checklist of the planktonic marine dinoflagellates of New Zealand - Lesley L. Rhodes; Kirsty F. Smith; Lincoln MacKenzie; Catherine Moisan (New Zealand Journal of Marine and Freshwater Research, 2020)
Planktonic dinoflagellate records for New Zealand are substantial due to intense monitoring programmes that have taken place on behalf of New Zealand’s biotoxin regulators and the shellfish industry since 1993. At that time a Karenia bloom caused human illnesses and shellfish harvesting ceased until monitoring was instigated. Phytoplankton records are based on morphological identification using light microscopy but are backed up by government funded research programmes which implement techniques such as electron microscopy, DNA sequencing, molecular detection assays and high throughput sequencing of environmental DNA. This checklist will support management of aquaculture industries, recreational shellfish harvests and environmental health initiatives. Some genera are considered benthic or epiphytic, but have lengthy planktonic life stages. Forty‐five genera in the class Dinophyceae Fritsch are reported: Akashiwo , Alexandrium, Amphidinium, Amylax, Azadinium, Biecheleria, Bysmatrum, Cachonina, Cochlodinium (synonym: Margalefidinium ), Coolia, Dicroerisma, Dinophysis, Diploneis, Diplopsalis, Fragilidium, Glenodinium, Gonyaulax, Gymnodinium, Gyrodinium, Heterocapsa, Karenia, Karlodinium, Lepidodinium, Lingulodinium, Margalefidinium, Ostreopsis, Oxyphysis, Pelagodinium, Pentapharsodinium, Phalacroma, Podolampas, Polarella, Polykrikos, Prorocentrum, Protodinium, Protoodinium, Protoperidinium, Pseliodinium, Scrippsiella, Takayama, Togula, Torodinium, Tripos, Vulcanodinium, Wolosynska. Other genera belonging to the Infraphylum Dinoflagellata also occur in New Zealand waters. They are not in the list but include Noctiluca, Pronoctiluca and Spatulodinium (Class: Noctilucophyceae) and Oxyrrhis (Class: Oxyrrhidophyceae).

Issue Information (Reviews in Aquaculture, 2020)

Chinese Abstracts (Reviews in Aquaculture, 2020)

Overview of strategies that contribute to the environmental sustainability of pond aquaculture: rearing systems, residue treatment, and environmental assessment tools - Matheus N.P. Henares; Mateus V. Medeiros; Antonio F.M. Camargo (Reviews in Aquaculture, 2020)
Aquaculture is responsible for almost 50% of the global production of aquatic organisms. However, the activity generates residues that cause environmental impacts. Several strategies can be adopted from the planning stage to the residue treatment to reduce these negative impacts. Alternative rearing systems, such as integrated multi‐trophic aquaculture ( IMTA ), integrated aquaculture‐agriculture systems, recirculation systems ( RAS ) and biofloc ( BFT ), can be implemented in place of the traditional monocultures. At the residue treatment stage, the solids particles can be removed by the settlement of suspended solids in tanks or mechanical filters. The reduction in dissolved nutrients is used in biological filters, constructed wetlands or the irrigation of agricultural crops. Finally, we describe the methodologies that are used to estimate the aquaculture environmental impacts. These methodologies allow the stages and processes that have a higher environmental impact in the production chain to be identified. Among them, we can highlight the life‐cycle assessment ( LCA ), emergy analysis and ecological footprint. The strategies described in this study can contribute to increasing aquaculture sustainability; however, studies should be developed that focus on more than just productivity and profitability, as it is necessary to include social and environmental issues.

Effects of dietary chitosan supplementation on farmed fish; a review - Heba M. Abdel‐Ghany; Mohamed El‐S. Salem (Reviews in Aquaculture, 2020)
Chitosan is a cationic polysaccharide that is primarily derived from chitin, a natural polymer of N‐acetyl glucosamine mainly found in crustacean, insect exoskeletons and fungal cell walls, by exhaustive alkaline deacetylation to varying degrees. Chitosan has been found to have many favourable biological properties including biosafety, biodegradability and biocompatibility. These advantages make it a very promising material for diverse applications. For terrestrial animals, chitosan has been widely used as a feed additive because of its low side effects, enhancing the growth performance, improving immune functions, inhibition intestinal microbial pathogens and lowering cholesterol. Recently, it has been used as a feed additive in fish diets. Moreover, chitosan has gained an attention as an effective agent in aquaculture water treatment. A number of studies have been conducted on the effectiveness of the use of chitosan in aquaculture. Thus, the present review explored the current state of knowledge on the effects of dietary chitosan on farmed aquatic animals including antimicrobial, growth promoting, antioxidant activity and immunostimulation effects, with a particular emphasis on the optimal dose of chitosan. As well as, this review pointed out the possibility of using chitosan in aquaculture water treatment. According to the studies that were discussed in this review, chitosan is considered as a promising material with a massive potential of applications in aquaculture.

Valuation of Ecosystem Services to promote sustainable aquaculture practices - Marco Custódio; Sebastián Villasante; Ricardo Calado; Ana Isabel Lillebø (Reviews in Aquaculture, 2020)
Conceptual frameworks to assess and valuate Ecosystem Services ( ES ) are rapidly becoming important tools for ecosystem‐based management, as they support transdisciplinary approaches to ecological economics and expand current asset boundaries to include natural and social capital. An important area where such ES assessment frameworks could become relevant management tools is aquaculture. Aquaculture activities are an interconnected part of the ecosystem in which they exist and, under certain circumstances, can support many of the same fundamental ES provided by nature. But, in most cases, aquaculture typically increases provisioning services at the expense of the other services (regulation & maintenance and cultural services). To understand the capacity of ES valuation methods to expose existing ES trade‐offs in areas under aquaculture development, this study provides a literature review of publications that assessed and valuated ES delivered and/or impacted by aquaculture. In general, it seems that certain types of aquaculture do negatively impact overall ES delivery (e.g. intensive mangrove shrimp farming in Asia), yet certain modes of production (e.g. integrated multi‐trophic aquaculture) and cultured species (e.g. algae and certain bivalves) can have a positive impact on ES , not only improving provisioning services but also regulation and maintenance services and, potentially, cultural services. ES valuation methods provide important data that facilitate discussion among stakeholders and policymakers and should be included in marine and coastal management planning processes to foster a more sustainable aquaculture.

Advances and challenges in genetic engineering of microalgae - Carlos Fajardo; Marcos De Donato; Rafael Carrasco; Gonzalo Martínez‐Rodríguez; Juan Miguel Mancera; Francisco Javier Fernández‐Acero (Reviews in Aquaculture, 2020)
Knowledge at the molecular level of microalgae has obtained great scientific interest in recent years, because of their potential for biofuel production, as well as other highly valued molecules. Recent advances in the area of the genetic manipulation of microalgae open an entirely new field of possible applications for these organisms as biorefineries. This review represents a compendium that gathers the main milestones that have marked the area of genetic engineering in microalgae during the last decade, from classical techniques for the transformation and expression of transgenes, to the most avant‐garde techniques currently used for gene silencing and DNA edition, as well as a discussion about the future perspectives in this field.

Barriers and facilitators to shellfish cultivation - Michaela Fox; Matt Service; Heather Moore; Moira Dean; Katrina Campbell (Reviews in Aquaculture, 2020)
A literature review was conducted to determine the barriers and facilitators to shellfish cultivation using Northern Ireland ( NI ) as a case study. This review included 23 papers, published in 14 journals, indexed in the Web of Science database. The eligibility criteria included (i) peer‐reviewed articles or websites from key government or agency stakeholders in the aquaculture supply chain; (ii) had a primary focus on shellfish production; and (iii) made reference to the United Kingdom, Ireland or NI. Six key categories were identified as impacting the aquaculture sector: Economic, Environmental, Technical, Welfare, Political and Consumer factors. The most commonly cited codes within these categories included regulations, management decisions, environmental welfare, weather conditions, consumer needs and water quality. Within the scientific literature, the study designs were variable and NI ‐specific data were limited. However, the recommendations were relatively consistent. More evidence‐based data collection is needed to better establish the status of the aquaculture industry in this region and to provide more effective management practices and recommendations. The information gained from this review allowed the identification and discussion of the challenges and opportunities for shellfish production worldwide; an insight into production in NI ; and preliminary recommendations for improving this industry. As a result, the review offers important foundations and lessons for other aquaculture production units across the world to assess their industry.

Cryopreservation of spermatozoa on grouper species: a review - Che Ismail Che‐Zulkifli; Ivan Chong Chu Koh; Md Sheriff Shahreza; Mhd Ikhwanuddin (Reviews in Aquaculture, 2020)
Cryopreservation of spermatozoa of grouper species supporting artificial insemination in production of fry has contributed to the grouper aquaculture industry. Grouper is a high‐value species in marine cage finfish culture and a major business for the aquaculture industry in South East Asia. The species contributes a significant value to the income of South East Asian countries such as Indonesia, Malaysia, Philippines and Thailand. Hybrid grouper is a new candidate for marine finfish culture, and cryopreservation of grouper and giant grouper spermatozoa is important to support development of its production. This review article discusses the cryopreservation of the spermatozoa of grouper species specifically. Emphasis is placed on the protocols for implementation and implications of the cryopreservation of grouper spermatozoa in the marine finfish aquaculture industry.

The role of shrimp micro RNA s in immune response and beyond - Ramiro J. González‐Duarte; Fernando L. García‐Carreño (Reviews in Aquaculture, 2020)
Micro RNA s are a class of small non‐coding RNA s that regulate gene expression at post‐transcriptional level. Regulatory RNA s were discovered in the nematode Caenorhabditis elegans , since then, their biological functions have been studied on different animals, including marine organisms. Several species of penaeid shrimp are important in ecology and fishing, including aquaculture. Overcrowding in aquaculture calls for infectious diseases, which threaten the development of shrimp aquaculture worldwide. Given that micro RNA s play crucial regulatory roles in a wide variety of biological processes, there is a scientific interest to understand their contribution on shrimp physiology and pathology, specifically during immune and stress response. Increasing evidence has shown that the expression of micro RNA s is affected during virus or bacterial infection and upon stress in shrimp. This information provides valuable insights for a better understanding of shrimp biology by means of micro RNA regulation to bacterial and viral diseases.

Progress and perspectives of short‐chain fatty acids in aquaculture - Ngoc Tuan Tran; Zhongzhen Li; Shuqi Wang; Huaiping Zheng; Jude Juventus Aweya; Xiaobo Wen; Shengkang Li (Reviews in Aquaculture, 2020)
Gut microbiota is important and plays a crucial role in the host health and nutritional metabolism through multiple mechanisms. Short‐chain fatty acids (SCFAs), which are carboxylic acids with aliphatic tails

A global review of the ecosystem services provided by bivalve aquaculture - Andrew van der Schatte Olivier; Laurence Jones; Lewis Le Vay; Michael Christie; James Wilson; Shelagh K. Malham (Reviews in Aquaculture, 2020)
Bivalve shellfish aquaculture provides many benefits to society, beyond their traditional market value. This study collates the evidence available on the provisioning, regulating and cultural ecosystem services provided by the bivalve species commonly used in aquaculture. For the first time, it synthesises this evidence to provide a global assessment of the potential market and non‐market economic value of bivalve aquaculture. Bivalves are filter feeders, filtering water and particulates, creating substrates which provide habitat to act as nursery grounds for other species. Goods from provisioning services include meat, worth an estimated $23.9 billion as well as, pearls, shell and poultry grit, with oyster shell being the most important, with a global potential worth of $5.2 billion. The most important regulating services are nutrient remediation. Cultivated bivalves remove 49,000 tonnes of nitrogen and 6,000 tonnes of phosphorus, worth a potential $1.20 billion. Currently, there is little evidence on the cultural services per year of bivalve aquaculture, but we argue that these cultural values are broad ranging, although difficult to quantify. Our assessment indicates that the global, non‐food bivalve aquaculture services are worth $6.47 billion ($2.95 billion–9.99 billion) per annum. However, this is likely to be an underestimate of the true value of bivalve aquaculture as there are significant gaps in evidence of the value for a number of key services. The analysis presented here can be used to indicate the likely scale of payments for ecosystem services provided by bivalve aquaculture, prior to more detailed assessments.

Insight into aquaculture's potential of marine annelid worms and ecological concerns: a review - Ana Pombo; Teresa Baptista; Luana Granada; Susana M. F. Ferreira; Sílvia C. Gonçalves; Catarina Anjos; Erica Sá; Paula Chainho; Luís Cancela da Fonseca; Pedro Fidalgo e Costa; José L. Costa (Reviews in Aquaculture, 2020)
Polychaetes are marine annelid worms that can contribute to aquaculture diversification. Its culture has been viable, and commercially attempted, but intensive production has progressed only in few countries around the world. In the countries with no production, marine polychaetes are imported or harvested. A strong and sustained research investment provided to a better understanding of the nutritional requirements and reproduction of some species. Recent studies showed new technical improvements, which can lead to an important progress in productivity and give a new impetus to the polychaete production. Some marine worm species were identified as good candidates for integrated multitrophic aquaculture. The development of cost‐effective aquaculture techniques for marine annelid worms is essential to ensure a balance between commercial interests and the preservation of ecosystems. The influence of polychaete aquaculture on the environment and vice versa raise important concerns related to ecological security and sustainability of this activity. This review focus on the main technical improvements and advances that have been made in areas as diverse as: aquaculture potential of polychaetes , reared species, main species used worldwide, and highlights biological and ecological concerns, important challenges and recommendations.

Multi‐stakeholder perspectives on spatial planning processes for mariculture in the Mediterranean and Black Sea - Richard A. Corner; José Aguilar‐Manjarrez; Fabio Massa; Davide Fezzardi (Reviews in Aquaculture, 2020)
Aquaculture provides more than half of the fish used for human consumption, contributing to food security and nutrition, economic growth and improved livelihoods. Aquaculture production in countries bordering the Mediterranean and Black Sea has grown steadily, though not homogenously, mainly based on marine species. To boost development, there is a need to support governance to establish activities within a coordinated spatial planning process. Knowledge of aquaculture spatial planning processes are assessed through consultations with stakeholders from 21 countries using a structured questionnaire, internal review and a workshop to determine major barriers to the implementation in the region. Results suggest different levels of knowledge of regulatory systems in the countries surveyed. Aquaculture zoning is widespread. Site selection is a long and inefficient process, a barrier to investment, exacerbated by an apparent lack of a clear distribution of power and responsibilities. Area management is the least implemented part of the spatial planning process, with few examples of an integrated approach. Poor social acceptance of aquaculture, low technical knowledge and understanding of spatial planning concepts, and a lack of meaningful communication are among the problems highlighted by stakeholders. Although recent advances are evident, the integration of aquaculture with other users of marine space remains a work in progress that requires a specific regulatory framework, capacity building, transparency, good communication and participatory processes. Application of spatial planning following an ecosystem approach to aquaculture can contribute to improvements that have the potential to counter the negative externalities of unplanned or uncoordinated development.

Nutrition and Feeding Aspects for Jundiá ( Rhamdia quelen ) Rhamdia quelen Nutrition and Feeding - Hanna Karolyna dos Santos; Fabio Meurer (Reviews in Aquaculture, 2020)
The jundiá or silver catfish ( Rhamdia quelen Quoy & Gaimard, 1824) is species native to the Americas, omnivorous, with a tendency towards carnivorous feeding habits. The species presents commercial potential, and therefore, knowledge on its nutritional requirements, as well as basic feed ingredients, is essential. Its tendency towards carnivorous feeding habits leads to some concerns regarding plant ingredient digestion abilities, although rice, soybean, flax, sorghum, ground corn or oat bran can be used as feed ingredients for this species, since they present good digestibility coefficients. In order to guarantee adequate performance of metabolic, immunological and reproductive functions, jundiá feed can be supplemented with micronutrients that minimize the effects of antinutritional factors present in plant ingredients. Plant ingredients present several economic advantages such as suitable quality, competitive prices and the fact that they are widely available in South Brazil.

A Proteomics and other Omics approach in the context of farmed fish welfare and biomarker discovery - Cláudia Sofia Ferreira Raposo de Magalhães; Marco Alexandre Cavaco Cerqueira; Denise Schrama; Márcio Júlio Vicente Moreira; Surintorn Boonanuntanasarn; Pedro Miguel Leal Rodrigues (Reviews in Aquaculture, 2020)
The rapid and intensive growth of aquaculture over the last decade, poses a tremendous challenge to this industry in order to comply with the latest guidelines, established to minimise its negative effects on the environment, animal welfare and public health. Farmed fish welfare has become one of the main priorities towards sustainable aquaculture production with several initiatives launched by the European Union within the framework of the 2030 agenda. It is clear that an unbiased and reliable way to access farmed fish welfare needs to be implemented due to the lack of reliable indicators and standardised methods that are used at present. In this review, we start by addressing the status quo of animal and fish welfare definition in particular, describing the methods and assays currently used to measure it. We then explain why we believe these methods are unreliable and why there is a need to establish new ones that will promote productivity and consumer's acceptance of farmed fish. The establishment of a new type of welfare biomarkers using cutting‐edge technologies like proteomics and other omics technologies is proposed as a solution to this issue. Therefore, we provide a brief description of these new methodologies, describing for each one how they can improve our scientific knowledge and the role they can play in farmed fish welfare biomarker discovery.

Applications of microalga Chlorella vulgaris in aquaculture - Muhammad Talba Ahmad; Mohamed Shariff; Fatimah Md. Yusoff; Yong Meng Goh; Sanjoy Banerjee (Reviews in Aquaculture, 2020)
Microalgae biomass is used in aquaculture as feed, growth enhancers and immunostimulants. Chlorella vulgaris is an important species with a good biomolecular composition. Commercially, it is one of the most commonly used microalga in aquaculture. Several studies confirmed its ability to improve nutrition, immunity, aquatic bioremediation, amelioration of stress, disease resistance of fish and inhibits bacterial quorum sensing when used appropriately. Despite claims of its benefits, C. vulgaris is reported to have unfavourable effects when incorporated in diets at higher inclusion levels. In addition, its rigid cell wall might restrict the access of digestive enzymes to the intracellular components for proper digestion and assimilation. Thus, this review discusses the role of C. vulgaris and its importance in aquaculture with emphasis on its environmental requirements, morphology, pigments, digestibility, dynamics on growth performance, antibacterial activity, bacterial quorum sensing, immunomodulatory effect, anti‐stress effect, gut microbiome, aquatic bioremediation and its safety as food or feed.

New insight into the diversity of exon and intron 5 regions of Oncorhynchus mykiss growth hormone (GH) gene: sexual dimorphism in the GH gene - Tahereh Akbarialmajough; Ramin Manaffar; Ebrahim H. Najdegerami; Peter Bossier (Reviews in Aquaculture, 2020)
The growth in vertebrates is controlled by growth hormone ( GH ) gene which is a member of the somatotropin/prolactin family. In salmonids, a series of gene duplications is thought to have occurred in GH gene. In this family, the diversity in intron and exon regions of the GH gene is assumed to be not only in charge of a different growth rate but also in sex maturation. Due to the sex determination importance in salmonids, especially during early stages of development, in present study, an easy and accurate molecular marker was investigated for sex determination of Oncorhynchus mykiss fish using the diversity of the exon and intron 5 of GH gene. A pseudogene ( GH ‐ψ) copy of growth hormone gene was found on the Y chromosome which is in homology with type‐2 GH genes that can be used for sexual dimorphism of this species. This pseudogene was detected using a specific primer pairs combination using polymerase chain reaction ( PCR ) to select monosex female population. As recent findings suggest new functions of pseudogenes in the regulation of gene expression, it is believed that the putative gene could have an impact on GH expression in this species.

Mycotoxins in aquaculture: feed and food - Rui A. Gonçalves; Dian Schatzmayr; Amaya Albalat; Simon Mackenzie (Reviews in Aquaculture, 2020)
Mycotoxins, secondary metabolites produced by moulds, are responsible for causing significant economic losses due to spoilage of agricultural products but also due to direct or indirect health impact on livestock upon ingestion of mycotoxin contaminated feedstuffs. Aquaculture farmed species are not an exception and studies reporting mycotoxin‐related issues in the aquaculture industry have been increasing. However, our understanding on the prevalence and impact of mycotoxins in the aquaculture sector is still lower compared to the terrestrial livestock sector. Consequently, regulatory limits and guidance values have been defined based on the studies on terrestrial farm animals. The aim of this review is to compile and critically assess mycotoxin occurrence and co‐occurrence in aquaculture finished feeds, and understand the risk of mycotoxin carry‐over in aquaculture seafood products. Furthermore, we aim with this review to raise awareness to the scientific community, the regulatory authorities and the aquaculture industry to the need for specific aquaculture mycotoxin maximum concentration levels for both aquaculture feeds and foods.

Potential biomarkers of DNA quality in cryopreserved fish sperm: impact on gene expression and embryonic development - Elías Figueroa; Manuel Lee‐Estévez; Ivan Valdebenito; Jorge G. Farías; Jaime Romero (Reviews in Aquaculture, 2020)
Sperm DNA quality and gene expression are crucial for early embryo development. Abnormal genomic processes can cause irreversible damage to totipotent cells, thereby altering the capacity for cell differentiation. Cryopreservation is a complex procedure that exposes cells to extreme conditions; it is therefore important to determine whether cryopreservation affects genomic stability. Despite this, few studies have focused on the effects of cryopreservation on the genomic stability of fish sperm. Thus, information is lacking to determine how the cryopreservation of fish sperm affects embryo quality and subsequently aquaculture. The aim of this review was to compile background information pertaining to the study of genomic stability in cryopreserved sperm. In this way, we hope to characterize more clearly the embryonic development of fish that are of biological and economic interest. We also discuss the potential use of antioxidants in cryopreservation to help preserve DNA integrity, gene expression and embryo quality. There is a current need to evaluate the use of potential biomarkers of genomic integrity to establish the effects of cryopreservation on the DNA quality of fish gametes and embryos.

Environmental colour impact on the life of lower aquatic vertebrates: development, growth, physiological and biochemical processes - Alexander B. Ruchin (Reviews in Aquaculture, 2020)
This review discusses environmental colour impact on such vital processes of lower aquatic vertebrates (amphibian and fish), as development, growth, consumption of food and its conversion ratio, secretion of hormones etc. For some species, different zones of the spectrum can act as a stimulator of growth and development processes, while other zones of the spectrum can, on the contrary, inhibit development and growth. This influence occurs at the physiological and biochemical levels. Physiologically, environmental colour can both activate and suppress fish nutrition. Changes in daily ration can change the food conversion ratio. In turn, the contrast of the feed against a particular environmental colour can also affect the amount of food consumed and the somatic growth respectively. Certain zones of the spectrum stress fish, which is confirmed by the increase in cortisol level. Illumination of certain colour can accelerate fish growth; in such cases, a decrease in cortisol is observed. Environmental colour also affects the secretion of other hormones (somatotropin, thyroxine) and, as a consequence, the biochemical and physiological status of organisms. There is certain amount of evidence that environmental colour can impact gene expression and thereby regulate the somatic growth and development of fish and amphibians. However, there is not yet enough evidence and only preliminary conclusions can be drawn, which must be taken into account in fish breeding practice. A brief description of the organs of vision of lower vertebrates is given. The problems of the influence of light on a number of biochemical parameters are discussed.

Facts, truths and myths about SPF shrimp in Aquaculture - Victoria Alday‐Sanz; James Brock; Timothy W. Flegel; Robins McIntosh; Melba G. Bondad‐Reantaso; Marcela Salazar; Rohana Subasinghe (Reviews in Aquaculture, 2020)
Shrimp domestication and genetic improvement programmes began in late 1980s, in the United States of America, under the United States Marine Shrimp Farming Program ( USMSFP ), using the Pacific whiteleg shrimp Penaeus vannamei . The USMSFP was based on proven concepts from the livestock and poultry industries and began with establishing a specific pathogen‐free ( SPF ) shrimp stock. The original shrimp stock was obtained using rigorous screening of captured wild shrimp for selection of individuals naturally free of major shrimp pathogens. Although the concept of SPF animals was well defined for terrestrial animals, it was relatively new for aquaculture, and it took some time to be adopted by the aquaculture community. In the early 1990s, parallel to USMSFP , several other programmes on genetic improvement of shrimp were also initiated in Latin America. Subsequently, several new terminologies and products, such as specific pathogen resistant ( SPR ) shrimp, specific pathogen tolerant ( SPT ) shrimp and even ‘all pathogen exposed’ ( APE ) shrimp, entered the shrimp industry vocabulary and became commercial. This led to confusion in the shrimp industry about the meaning, relationship and significance of these new terms with respect to SPF . This position paper attempts to clarify these concepts, provide science‐based definitions, reconfirms the importance of developing, maintaining and using domesticated, specific pathogen‐free ( SPF ) shrimp stocks (which may also achieve SPR and/or SPT status) to reduce the risk of disease outbreaks and increase production and profit. The same principles would apply to development of domesticated SPF stocks for other species used in aquaculture. The paper also discusses the difficulties of confirming and certifying SPF status due to the presence of endogenous viral elements ( EVE s) and calls for internationally agreed science and evidence‐based technical guidelines for producing healthy shrimp.

Metabolomics and fish nutrition: a review in the context of sustainable feed development - Simon Roques; Catherine Deborde; Nadège Richard; Sandrine Skiba‐Cassy; Annick Moing; Benoit Fauconneau (Reviews in Aquaculture, 2020)
Aquaculture is facing a strategic challenge to improve feed suitability and support the global increase in fish production. Improvements in diet formulation for sustainable nutritional strategies have focused to date on the partial substitution of marine resources by plant resources but will now include other alternative feedstuffs. Growth trials and body composition data provide valuable indicators of fish nutritional status, while omics technologies may contribute to a better understanding of fish nutrition and help to demonstrate how feed and nutrients act in fish metabolism. Metabolomic approaches give an insight into fish metabolism through a non‐targeted analysis of metabolites in tissues or biofluids that involve multiple factors affecting fish, such as nutrition. In this review, we highlight the outcomes of publications in metabolomics applied to fish nutrition. We explain the concept of metabolomics and discuss specific technical considerations related to sample type, sampling and sample preparation. We show how metabolomic studies help to elucidate the impact of nutrition on fish fillet composition and fish metabolism. Finally, we describe the potential applications of metabolomic approaches for the non‐invasive monitoring of fish nutritional status.

Antimicrobial peptides of fish: innocuous alternatives to antibiotics - Preeti Chaturvedi; Raja Aadil Hussain Bhat; Amit Pande (Reviews in Aquaculture, 2020)
Antimicrobial peptides ( AMP s) are the key components of the innate immune system and perform the various biological function which offers immunocompetence and homeostasis to the living organisms. Owing to their multidimensional properties, they can find an important role in therapeutics for the treatment of emerging diseases in fishes. Several AMP s are reported in fishes, including defensins, cathelicidins, hepcidins, histone‐derived peptides and piscidins having board antimicrobial spectrum. Various factors are necessary for the induction of AMP s expression like pathogen‐associated molecular patterns and damage‐associated molecular pattern. Moreover, with beneficial effects, AMP s are coupled with rare concerns which should be considered before bringing them under the label of ‘harmless alternative to antibiotics’.

Antimicrobial peptides from fish: beyond the fight against pathogens - Yulema Valero; Miguel Saraiva‐Fraga; Benjamín Costas; Francisco A. Guardiola (Reviews in Aquaculture, 2020)
Fish antimicrobial peptides ( AMP s) are small peptides whose actions have great implications in the innate immune response of teleost fish, being considered critical as the first line of defence against a wide spectrum of pathogens. Antibiotics have been widely used in aquaculture, resulting in bacterial resistance. The potential of AMPs as alternative to antibiotics makes them a very interesting tool as they represent lower‐risk peptides to develop resistances, or even in the fight against other pathogens such as viruses. Beyond their antimicrobial function, fish AMP s possess several relevant but little‐known characteristics and capabilities such as host‐defence peptides, antioxidants, active compounds of immunogenic drugs and as adjuvants. Moreover, their antitumour properties make them potential drugs to be used in oncological treatments in human subjects. Novel methodologies as clustered regularly interspaced short palindromic repeats associated proteins system ( CRISPR ‐Cas), or even their use as nutraceutics, seem to be promising instruments to enlarge the functions of fish AMP s. This review discusses these new methodologies, as well as the latest research on fish AMP functions, newly discovered properties of AMP s and their future applications in both the aquaculture industry and human health care.

Innovative protein sources in shrimp ( Litopenaeus vannamei) feeding - María José Sánchez‐Muros; Patricio Renteria; Antonio Vizcaino; Fernando G. Barroso (Reviews in Aquaculture, 2020)
Shrimps are one of the most important cultures in aquaculture with an estimated production of around 4.5 million MT , that is constantly growing. This fact entails the necessity to increase aquafeed production to meet demand. As in other aquaculture species, fishmeal ( FM ) is the main protein source used in shrimp feeding. In this context, the current review summarises several innovative protein sources for shrimp nutrition, focusing primarily on those sources that are less commercialised including fishery by‐products, terrestrial animal by‐products, single‐cell proteins, grain legumes, plant protein concentrates and cereal by‐products, with emphasis placed on novel raw materials in experimental phase: algae, insect meal or biofloc. Nutritive values, inclusion levels and constraints are discussed.

Performance measures and models for open‐water integrated multi‐trophic aquaculture - Gregor K. Reid; Sébastien Lefebvre; Ramón Filgueira; Shawn M.C. Robinson; Ole J. Broch; Andre Dumas; Thierry B.R. Chopin (Reviews in Aquaculture, 2020)
Qualifying and quantifying nutrient flows within open‐water Integrated Multi‐Trophic Aquaculture ( IMTA ) systems is necessary to determine transfer efficiencies and to assess overall system performance. There are numerous empirical performance metrics, such as spatially defined growth and nutrient sequestration, which may have application. When used in combination with modelling techniques, empirical approaches can be a powerful tool for system assessment or prediction. Simple empirical growth models, such as the thermal‐growth coefficient ( TGC ) and scope for growth ( SFG ), are applicable to aquatic animals and can include nutritional mass‐balance approaches to estimate nutrient loads. Comparable empirical growth models exist for seaweeds. Mechanistic‐based dynamic growth and reproduction models, such as Dynamic Energy Budget ( DEB ), are more complex, but have application beyond site‐specific empirical models and can, therefore, be included into larger ecosystem models for application to IMTA . Proximity, ecological transfer efficiencies, particle dynamics, species culture ratios and the timing of multi‐species production cycles can have profound implications for IMTA effectiveness and require careful consideration for system assessment. This review provides a pragmatic evaluation of performance measures and models to assess nutrient transfer and growth in open‐water IMTA systems.

Shellfish culture: a complex driver of planktonic communities - Vivien Hulot; Denis Saulnier; Céline Lafabrie; Nabila Gaertner‐Mazouni (Reviews in Aquaculture, 2020)
This review features recent updates on planktonic community alteration attributed to shellfish farming across three major drivers: predation, nutrient availability and the hydrodynamic environment. The grazing pressure generated by filter‐feeder communities (shellfish and epibionts) constitutes a ‘top‐down’ control of planktonic communities in aquaculture areas, inducing a significant depletion of planktonic organism concentration. By selecting larger cells during the filtration process, shellfish also favour smaller organisms in the water column, leading to the dominance of the latter. Direct excretion and the benthic alteration process tend to fertilise the water column and significantly stimulate primary production. The associated epibiont community particularly contributes to this regeneration process. The expected consequence of increasing nutrient availability is generally a planktonic shift in favour of small planktonic species. However, investigation on the relationship between planktonic structure and nutrient conditions has revealed a wide complexity and variability. Finally, all structures used in shellfish farming activities interact with water currents and tend to significantly increase the residence time of planktonic organisms inside shellfish farming areas. In grazing‐dominated systems, an increase in residence time tends to increase the exposure time of planktonic populations to detrimental conditions, reducing biomass and production. The general consequences of shellfish farming are a decrease in primary production in farming ecosystems, and a possible alteration of structure and functioning of planktonic communities. The implications of shellfish farming also appear to be quite different from other aquaculture activities such as fish farming, which tend to promote primary production leading to eutrophication process.

A review of the multiple benefits of mussel farming - Felipe Matarazzo Suplicy (Reviews in Aquaculture, 2020)
This review analyses how mussel farming can contribute to the challenge of feeding the current and future world population in a more efficient and sustainable way. The analysis lays a foundation of the main issues with current practices of animal protein production, and compares them with the alternative of a massive expansion of mussel farming as a means to produce high‐quality protein for human and animal nutrition. The review also covers the ecological goods and services that mussels provide to the ocean and to the atmosphere, the health of mussel products, and the many potential uses of by‐products from the mussel industry in agriculture, in wastewater treatment, and in the feed industry.

Phycocyanin sensors as an early warning system for cyanobacteria blooms concentrations: a case study in the Rotorua lakes - Vanessa Cotterill; David P. Hamilton; Jonathan Puddick; Alastair Suren; Susanna A. Wood (New Zealand Journal of Marine and Freshwater Research, 2019)
Cyanobacterial blooms pose health risks to recreational water users. In New Zealand, cyanobacteria biovolumes are used to assess risk, but analyses can be time‐consuming and costly. In this study, measurements from a handheld phycocyanin sensor (Cyclops‐7, Turner Designs, USA) were compared with biovolumes from five lakes and a river in the Rotorua district over two years (2016, n = 121; 2017, n = 63). In the laboratory, relationships between sensor phycocyanin and biovolumes were assessed for four species to investigate precision and detection limits. The relationship between phycocyanin and biovolume was generally weak ( R 2 = 0.4) and varied among lakes and years, except at high biovolumes. Precision and detection limits differed among species. The biovolume detection limit derived from relationships with phycocyanin was above alert level thresholds for two of the four cyanobacteria species assessed. The phycocyanin sensor that was tested likely has limited utility but may be useful for on‐site confirmation of exceedances of alert level thresholds corresponding to when authorities should immediately issue health warnings.

Assessing food web structure in relation to nutrient enrichment, macrophyte collapse and lake resilience in shallow lowland lakes - David J. Kelly; Marc Schallenberg (New Zealand Journal of Marine and Freshwater Research, 2019)
We examined food chain length and food web complexity as indicators for assessing shallow lake resilience from 18 lowland lakes, which included lakes in near‐reference condition through to lakes that had undergone catastrophic regime shifts. We observed a trend of decreasing food chain length and food web complexity in lakes that had undergone regime shifts. Across the full trophic gradient, food web metrics were correlated with factors related to trophic status (e.g. chlorophyll‐a) and macrophyte loss (e.g. exotic herbivorous fish), which have been previously associated with regime shifts in lakes. With increasing eutrophication, we identified a shift away from omnivory mostly in the lower trophic levels. Factors that impinge on macrophyte communities, such as nutrient loading and herbivory, reduce the resilience of shallow lake ecosystems, which is reflected in changes to lake food web structure. Thus, food web indicators can inform about the sensitivity of shallow lakes to eutrophication.

Lake resilience: concept, observation and management - Deniz Özkundakci; Moritz K. Lehmann (New Zealand Journal of Marine and Freshwater Research, 2019)

Long‐term changes in the water quality of a deep temperate oligotrophic lake in response to catchment disturbance: evidence from sediment cores - Alfred Theodore N. K. Kpodonu; David P. Hamilton; Christopher H. Lusk; Adam Hartland; Daniel C. Laughlin; Piet Verburg (New Zealand Journal of Marine and Freshwater Research, 2019)
This study examined long‐term stability in water quality of Lake Okataina, North Island, New Zealand, inferred from sediments deposited from 1836 to 2009, during which time there was a pyroclastic volcanic eruption (Tarawera 1886) and successive introductions of invasive mammals. Multiple geochemical proxies were analysed stratigraphically for organic matter loading, primary productivity, redox potential and phosphorus retention capacity. Organic matter loading to the lake is mostly authochthonous (algae) although there was increased allochthonous (terrestrial) loading immediately after the Tarawera eruption. After 1920, there was a sustained increase in inorganic erosion flux. Primary productivity appeared to increase considerably about 1960, but has remained relatively unchanged more recently. Our results suggest that the lake could recover from the impact of the volcanic eruption within a few decades, but the introduction of mammals may affect its resilience and lead to more pervasive impacts on the biogeochemistry.

Regional trends in remotely sensed water clarity over 18 years in the Rotorua Lakes, New Zealand - Moritz K. Lehmann; Uyen Nguyen; Kohji Muraoka; Mathew G. Allan (New Zealand Journal of Marine and Freshwater Research, 2019)
Observations by satellite sensors provide data on inland water systems at spatial and temporal coverage superior to current monitoring programmes. We derived an empirical relationship for Secchi depth using in situ data from eight lakes and data from the Landsat 5 Thematic Mapper, Landsat 7 Enhanced Thematic Mapper Plus and Landsat 8 Operational Land Imager between 1999 and 2018 in the Rotorua Lakes Region in New Zealand. This relationship was then applied to all Landsat data of 23 lakes in that region. A trend analysis on annual and summertime averages of Secchi depth revealed several statistically significant and positive trends, indicating improving water clarity. Our trends were in agreement with those based on in situ observations illustrating the opportunities of remote sensing time series data for lake monitoring and management.

Stressor‐response relationships and the prospective management of aquatic ecosystems - Scott T. Larned; Marc Schallenberg (New Zealand Journal of Marine and Freshwater Research, 2019)
Scientists and environmental managers use stressor‐response (S‐R) relationships to characterise and predict ecological and socioeconomic responses to anthropogenic stressors in lakes and other aquatic ecosystems. S‐R relationships with thresholds (stressor levels beyond which small increases cause large responses) are reported with increasing frequency. Threshold responses pose risks of unanticipated degradation, but also provide a stimulus for shifting environmental management strategies from retrospective (focused on post‐hoc responses to degradation) to prospective (focused on preventing degradation). We set out a framework for interpreting S‐R relationships in terms of functional forms, trajectories, thresholds and slopes. These characteristics convey information about resistance to degradation and recovery, risks of threshold exceedance, and alternate stable states. We then set out steps for implementing threshold‐based management strategies, which are based on forecasting S‐R relationships and carrying out preventative actions within an adaptive framework. Prospective, threshold‐based management is a challenging yet promising alternative to the prevailing retrospective strategies.

Patterns and drivers of spatio‐temporal variability of suspended sediment in the Waikato lakes, New Zealand - Deniz Özkundakci; Mathew Grant Allan (New Zealand Journal of Marine and Freshwater Research, 2019)
Quantifying and interpreting variability in ecological systems allows us to better understand the driving forces that determine ecosystems functioning. We utilised earth observation‐based remote sensing to determine total suspended sediment (TSS) concentrations for 109 lakes over 16 years. The coefficient of variation (CV) was used to quantify variability of TSS at three temporal scales (monthly, annual and long‐term) and at the horizontal spatial scale. CV values varied between 0.14 and 1.09. Drivers of observed variability patterns were explored using five lake morphological and catchment characteristics. Lake area was the most important variable to predict variability of TSS. De‐vegetated lakes displayed significantly higher TSS concentrations than vegetated lakes; however, aquatic vegetation was found to moderate only spatial variability of TSS. As spatio‐temporal variability can be assumed to drive key ecosystem functions, determining characteristic variability patterns for various attributes should be a prerequisite when setting management goals and developing monitoring regimes.

Characteristics of consumer trophic resources for Waikato shallow lake food webs - Kevin J. Collier; Jeremy Garrett‐Walker; Deniz Özkundakci; Michael A. Pingram (New Zealand Journal of Marine and Freshwater Research, 2019)
We characterised the quantity (mass per unit area or volume), quality (cabon:nitrogen ratio) and enrichment (δ 15 N) of basal food resources and benthic macroinvertebrates in six shallow lakes in the Waikato region, New Zealand, to elucidate patterns related to lake type (peat, riverine), habitat (littoral, mid‐lake) and enrichment status (Trophic Level Index >6 or ≤5). Total seston dry mass was dominated by fine material that was correlated with chlorophyll a concentration. Seston was a higher quality food resource than benthic particulate organic matter which had higher biomass overall in littoral than in mid‐lake habitats. Biomass of Chironomidae was highest in the less‐enriched peat lakes, possibly due to clearer water supporting benthic algae in shallow littoral areas. Our results highlight the potential role of multiple bottom‐up influences on shallow lake food webs. The more abundant and higher quality pelagic food resources in highly enriched lakes may have implications for resilience to non‐indigenous fish invasion.

Chinese Abstracts (Reviews in Aquaculture, 2019)

Issue Information (Reviews in Aquaculture, 2019)

Transcriptomics in aquaculture: current status and applications - Sathyajith Chandhini; Vattiringal Jayadradhan Rejish Kumar (Reviews in Aquaculture, 2019)
Transcriptomics is the analysis of total RNA transcript in a cell, which gives a broad idea of cellular processes that are active and dormant. Recent advancement in next‐generation sequencing technologies like high‐throughput mRNA sequencing ( RNA ‐seq) facilitates in deciphering the functional complexity of the whole transcriptome of an organism. In the recent past, transcriptome profiling has been widely used in aquaculture for effective identification and expression analysis of candidate genes involved in growth, reproduction, development, immunity, disease, stress and toxicology. On the paucity of a comprehensive genome sequence, transcriptomics enables the detection of molecular markers such as simple sequence repeats and single‐nucleotide polymorphism associated with the trait of interest. This review summarizes the process of transcriptome analysis and the current state of transcriptomics in aquaculture related to diseases and immunity, reproduction and development, growth and nutrition, toxicology and stress. Further, this review highlights the application of transcriptomics, including generation of genetic resources, differential gene expression, analysis of molecular pathways and development of molecular markers.

The metabolic regulation of dietary L‐carnitine in aquaculture nutrition: present status and future research strategies - Ling‐Yu Li; Samwel M. Limbu; Qiang Ma; Li‐Qiao Chen; Mei‐Ling Zhang; Zhen‐Yu Du (Reviews in Aquaculture, 2019)
L‐carnitine is a multi‐functional nutrient which plays a leading role in fatty acid metabolism in mammals and other eukaryotes. Its main physiological function is to promote fatty acid β‐oxidation to produce energy, which reduces body fat content and improves body weight without affecting moisture content in whole body and muscle. In recent years, its dietary supplementation in aquaculture nutrition has been studied in different cultured species. It has been proved that L‐carnitine can improve growth and increase lipid utilization rate in some aquatic animals. However, such beneficial effects of dietary L‐carnitine are limited or absent in other species. The reasons for the conflicting results obtained on L‐carnitine functions in aquatic animals need to be elucidated. This review explores comprehensively the different physiological functions of L‐carnitine in various aquatic animals. In the end, research strategies are provided to elucidate the existing conflicts on dietary L‐carnitine application in aquaculture nutrition in order to promote its utilization in aquatic feed industry.

Sustainable alternatives to dietary fish oil in tropical fish aquaculture - Ramez Alhazzaa; Peter D. Nichols; Chris G. Carter (Reviews in Aquaculture, 2019)
Marine tropical carnivorous (MTC) fish are less tolerant to high dietary lipid compared with cold and temperate climate fish. However, insufficient n‐3 long‐chain (≥C 20 ) polyunsaturated fatty acids (LC‐PUFA) compromises MTC fish health and growth which requires attention when choosing lipid sources in aquafeed formulations. Fish oil (FO) has been the major lipid source for feeding key MTC fish. We estimated that more than 200 thousand tonnes of FO were used to feed farmed MTC fish in 2016, representing nearly 25% of global FO production. Nevertheless, recent increases in FO prices and demand, and the foreseen inability of wild fisheries to produce sufficient FO in the future, have created a need for cheaper and more sustainable alternatives. Meta‐analysis showed that feeding vegetable oils (VO) to MTC fish can slightly reduce their growth, with a marked decrease in n‐3 LC‐PUFA content in the fish tissues corresponding with the increased replacement of FO and fishmeal in the diet. Rendered terrestrial animal fat or modulating the bioconversion of n‐3 LC‐PUFA precursors in VO can be utilised further in MTC fish nutrition with more research recommended on these approaches. Oils and oil‐rich meals from non‐food marine organisms are rich in n‐3 LC‐PUFA and represent an underutilised alternative to FO for tropical aquaculture. With oils rich in n‐3 LC‐PUFA produced from transgenic plants presently gaining regulatory approvals and becoming available as a renewable alternative to FO, aquaculture in the tropics and around the globe is ready to leap into a new phase of sustainable expansion.

Omics approaches to investigate host–pathogen interactions in mass mortality outbreaks of Crassostrea gigas - Thao V. Nguyen; Andrea C. Alfaro; Fabrice Merien (Reviews in Aquaculture, 2019)
Mass mortality events are routinely reported in bivalve cultivation practices worldwide with significant economic consequences for the global aquaculture industry. Major contributors of these bivalve losses are infections caused by viruses and bacteria whose molecular action mechanisms are still not fully understood. This major bottleneck for shellfish cultivation presents an opportunity for fundamental research that can generate practical tools for reliable health assessments. To this end, newly developed omics approaches are likely to facilitate knowledge acquisition, especially if applied in conjunction with established and emergent immunological techniques. In recent years, various omics technologies (e.g. genomics, transcriptomics, proteomics and metabolomics) have been used to study the Pacific oyster mortality events associated with detection of ostreid herpesvirus type 1 (Os HV ‐1) and Vibrio bacteria. These new approaches, especially when used in combination have significantly improved our understanding of this syndrome and associated diseases. In this paper, we review the current omics technologies that have been employed to investigate the interactions between Pacific oyster Crassostrea gigas and pathogens (e.g. Os HV ‐1 and Vibrio sp.), infection mechanisms, host susceptibility and resistance. Herein, we also highlight some of the current challenges and future directions of omics approaches in shellfish health research, including disease detection, diagnosis and treatment.

Impacts of marine and freshwater aquaculture on wildlife: a global meta‐analysis - Luke T. Barrett; Stephen E. Swearer; Tim Dempster (Reviews in Aquaculture, 2019)
The global expansion of aquaculture has raised concerns about its environmental impacts, including effects on wildlife. Aquaculture farms are thought to repel some species and function as either attractive population sinks (‘ecological traps’) or population sources for others. We conducted a systematic review and meta‐analysis of empirical studies documenting interactions between aquaculture operations and vertebrate wildlife. Farms were associated with elevated local abundance and diversity of wildlife, although this overall effect was strongly driven by aggregations of wild fish at sea cages and shellfish farms (abundance: 72×; species richness: 2.0×). Birds were also more diverse at farms (1.1×), but other taxa showed variable and comparatively small effects. Larger effects were reported when researchers selected featureless or unstructured habitats as reference sites. Evidence for aggregation ‘hotspots’ is clear in some systems, but we cannot determine whether farms act as ecological traps for most taxa, as few studies assess either habitat preference or fitness in wildlife. Fish collected near farms were larger and heavier with no change in body condition, but also faced higher risk of disease and parasitism. Birds and mammals were frequently reported preying on stock, but little data exist on the outcomes of such interactions for birds and mammals – farms are likely to function as ecological traps for many species. We recommend researchers measure survival and reproduction in farm‐associated wildlife to make direct, causal links between aquaculture and its effects on wildlife populations.

The lesser mealworm Alphitobius diaperinus : a noxious pest or a promising nutrient source? - Christos I. Rumbos; Ioannis T. Karapanagiotidis; Eleni Mente; Christos G. Athanassiou (Reviews in Aquaculture, 2019)
The lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), is one of the most common insect pests in commercial poultry farms, where it reproduces within the litter floor, feeding on poultry manure, spilled feed and other organic material. It can also infest, feed and reproduce on stored grains and related amylaceous commodities. Its significance is related mostly with the fact that it serves as reservoir and vector for many pathogens that cause serious diseases, such as Salmonella, Escherichia and various viruses. Recently, A. diaperinus attracted a lot attention as it was listed in the EU Regulation 2017/893 among the insect species that are allowed to be used for the production of insect meal as aquafeed ingredient, changing our perspective on this insect from a noxious pest to a potential nutrient source. This is the first review on A. diaperinus summarizing the significant recent findings in its biology and control. Moreover, this review aims to provide a helpful tool for aquaculture scientists working with A. diaperinus as aquafeed ingredient. Therefore, we gather and highlight the available data that classify A. diaperinus as a promising insect‐based protein provider and we comment and discuss on the public concerns that arise from its utilization as feed.

Feasibility of the use of Spirulina in aquaculture diets - Victor T. Rosas; Luís H. Poersch; Luis A. Romano; Marcelo B. Tesser (Reviews in Aquaculture, 2019)
The growth of aquaculture depends on protein sources that can reduce the pressure on fishmeal ( FM ), and Spirulina feed could be an option due to its high nutritional value. Studies on Spirulina as a food in diets of aquatic organisms have increased substantially in the past decade, but the fact that its use in commercial rations does not occur today indicates that there are still challenges that need to be overcome. This review attempts to compile most of the work carried out through today in aquaculture that uses Spirulina as an FM substitute and as a functional feed. The high cost of Spirulina can be compensated if it is used in small quantities because it can improve the health and growth of organisms, compensating for its high economic cost by reducing costs in other production areas.

A systematic quantitative literature review of aquaculture genetic resource access and benefit sharing - Fran Humphries; John A.H. Benzie; Clare Morrison (Reviews in Aquaculture, 2019)
The Convention on Biological Diversity provides a framework for countries to implement laws regulating the access, use and exchange of genetic resources, including how users and providers share the benefits from their use. While the international community has been preoccupied with resolving the unintended effects of access and benefit sharing ( ABS ) on domestication in agriculture for the past 25 years, its far‐reaching consequences for global aquaculture has only recently dawned on policymakers, aquaculture producers and researchers. Using a systematic quantitative literature review methodology, we analysed the trends, biases and gaps in the ABS literature. Only 5% of the ABS literature related to the use and exchange of aquaculture genetic resources. Most of this literature related to use in developing countries or global use, but its authors were predominantly from developed countries. The literature covered a narrow range of countries (7) and regions (3), a narrow range of taxonomic groups (9) and a narrow range of uses. Given that aquaculture is the fastest growing global food production sector with products primarily from developing countries using over 580 species, there are significant gaps in aquaculture‐related ABS literature. We conclude that the sector needs urgent analyses on the consequences of ABS restrictions, obligations and opportunities for its early stages of domestication and product development. We recommend priority areas for attention to ensure that rapidly evolving national ABS laws take into account the special characteristics and needs of the aquaculture sector.

Influences of immunostimulants on phagocytes in cultured fish: a mini review - Emmanuel D. Abarike; Felix K.A. Kuebutornye; Jichang Jian; Jufen Tang; Yishan Lu; Jia Cai (Reviews in Aquaculture, 2019)
Lower vertebrates like fish mostly depend on innate immunity as the first line of defence against invading pathogens. One of the defence mechanisms in innate immunity for fish is the use of phagocytic cells such as monocytes, macrophages, neutrophils, mast cells and dendritic cells in fighting pathogens. These cellular cells employ a variety of mechanisms in protecting fish including but not limited to; the use of pattern recognition receptors and antigen presenting cells to detect the presence of pathogens in host, neutralising them using measures including; inflammation, production of lysosomal enzymes released into the phagosome to neutralising pathogens and prevention of systemic autoimmunity by apoptosis. Some phagocytic cells play the extra role of serving as a bridge between innate and adaptive immunity in fish. Recent accumulating data showed that phagocyte cell activity in fish could be enhanced by a natural or chemical substance (immunostimulants) that stimulates the immune system in fish principally meant to enhance the immune response mechanisms. In this review, the main focus is on elucidating the distinct phagocytic mechanisms played by monocytes, macrophages, neutrophils, mast cells and dendritic cells as principal phagocytes in immune defence and how their activities are influenced by immunostimulants in cultured fish.

Nutrition, growth and resilience of tiger grouper ( Epinephelus fuscoguttatus ) × giant Grouper ( Epinephelus lanceolatus ) hybrid‐ a review - Rossita Shapawi; Faihanna Ching Abdullah; Shigeharu Senoo; Saleem Mustafa (Reviews in Aquaculture, 2019)
The hybrid grouper discussed in this paper is a cross between female tiger grouper ( Epinephelus fuscoguttatus ) and male giant grouper ( Epinephelus lanceolatus ). Performed for the first time at this institute, the hybridization was motivated by the need to meet grouper demand. The hybrid has been a subject of thorough scientific investigations ever since it was produced. Qualities such as dietary needs, efficiency in growth and production and environmental resilience are of considerable aquaculture advantage, and account for interest in its commercial‐scale farming in the wider Asia‐Pacific region. This paper reviews scientific evidences on tolerance of hybrid grouper to environmental variability, nutrition, growth and genetic and other aspects. It makes serious attempt to summarize the pertinent data published on specific research questions to improve understanding of the diverse evidences, and to be able to identify gaps in knowledge. This has helped in articulating the current state of research and defining topics for future studies on the hybrid. From the analysis of published data it is obvious that hybrid has a higher production potential and resilience. Nevertheless, the hybrid is vulnerable to health problems linked to nutritional deficiencies and other factors. More comprehensive data on dietary requirements of the hybrid, especially larval stages, will help in formulating feeds that cater to metabolic requirements and improve the survival and biomass gains. Information on hybrid's dietary flexibility can be used in developing feeds for grow‐out stages comprising ingredients from sustainable sources. The hybrid could be a suitable candidate for adapting aquaculture to climate change.

Boom‐and‐bust production cycles in animal seafood aquaculture - Weiwei You; Dennis Hedgecock (Reviews in Aquaculture, 2019)
Although aquaculture has grown nearly exponentially over the last six decades, providing 31.6 million metric tons of animal seafood in 2015, its rate of growth has slowed over the last 15 years. Here, we use case studies, drawn mostly from Asian shellfish culture, to suggest that ‘boom‐and‐bust’ production cycles – periods of rapid growth followed by collapse – cause significant losses of seafood production and to illustrate the duration and repetition of boom‐and‐bust cycles. Next, using the global FAO database for aquaculture production from 1950 to 2015, we investigate whether boom‐and‐bust cycles occur more broadly and whether they are playing a role in the declining rate of global aquaculture production. Focusing on FAO production records with maxima before 2011, allowing time for collapse, we categorize production in each record, relative to its maximum value, as sustained, depleted, collapsed or lost. We find 278 of 453 records (61.4%) show collapsed or lost production, although production in most of these records comprises only a tiny fraction of global output. The top 30 records in the collapsed or lost categories do account for 2.4% of cumulative production over the 66‐year record of animal seafood aquaculture. We identify a strong association between short boom phases (5 years or less) and the probability that production will be lost and use this, as well as maximum annual production and year of maximum production, to model the probability of loss. Ecological limits and market problems are the most often discussed causes of boom‐and‐bust production cycles, but we focus, here, on disease as a major proximal cause of collapse and raise the hypothesis that inbreeding depression may often be an ultimate cause by exacerbating disease susceptibility.

Control of AHPND by phages: a promising biotechnological approach - Carlos Angulo; Abraham Loera‐Muro; Edgar Trujillo; Antonio Luna‐González (Reviews in Aquaculture, 2019)
Vibrio parahaemolyticus , V. campbellii , V. owensii and V. harveyi are causative agents of Acute Hepatopancreatic Necrosis Disease (AHPND) in shrimp. AHPND is recently one of the most important diseases worldwide because of the high mortality and huge economic losses in shrimp farms. Antibiotic resistance has caused concern into finding other options to fight against pathogenic bacterial diseases. Currently, the use of lytic phages has reemerged as a promising strategy to combat bacterial pathogens. Likewise, modern molecular tools have been applied to modify phages by genetic engineering to express specific antigens and antibodies. This study reviewed recent research reports in the development of phages to control Vibrio spp. infections in shrimp and discusses different specific strategies, placing them in perspective to combat AHPND.

Oxytetracycline in intensive aquaculture: water quality during and after its administration, environmental fate, toxicity and bacterial resistance - Joana F. Leal; Eduarda B.H. Santos; Valdemar I. Esteves (Reviews in Aquaculture, 2019)
Oxytetracycline ( OTC ) is one of the most used antibiotics in aquaculture. This raises concerns due to its effects in human and animal health, the environmental contamination and the consequences arising therefrom. This review focuses on the OTC application in intensive aquaculture. It compiles and complements the dispersed information, presenting a comprehensive study about the OTC effects, from its administration to farmed fish, until its release into the surrounding aquatic systems. Several topics about OTC are presented and discussed: physical–chemical properties, interaction with ions, application to farmed fish, effects in water quality and possible treatments, biological activity and toxicity of OTC by‐products, environmental fate. Based on the information gathered, one concludes that OTC establishes strong complexes with Ca 2+ and Mg 2+ , which may have implications on its biological activity. OTC acts as inhibitor of protein synthesis and is poorly metabolized or unmetabolized by fish. Its common recommended daily dose is about 75 mg kg −1 but depends on the administration conditions and on target fish species. Regarding OTC removal from water within a semiclosed aquaculture's water circuit, ozonation and photodegradation are not completely efficient methods as none of them promotes total mineralization. However, photodegradation can be applied as a complementary method prior to ozonation, allowing to reduce costs. OTC by‐products do not appear to retain its biological activity, but toxicity studies mimicking environmental conditions were not found. In open circuits (cages), water column where OTC is administered not suffer a specific treatment and the antibiotic is easily spread by the surrounding environments, affecting their inhabitants. OTC is released in the aquatic system in freely dissolved form and/or associated with organic or inorganic compounds, being subjected to natural photolysis, hydrolysis and/or biodegradation.

Adjuvant effects of medicinal herbs and probiotics for fish vaccines - Mehdi Soltani; Alan Lymbery; Seong Kyu Song; Pezhman Hosseini Shekarabi (Reviews in Aquaculture, 2019)
The most prominent limiting factor in aquaculture nowadays is infectious diseases as they lead to massive economic losses. These diseases are often partly controlled by vaccination, herbs or probiotics. Despite the fact that vaccination is the most effective prophylactic approach to disease prevention, researchers have started to use plant‐derived products and probiotics as adjuvants to boost the efficacy of fish vaccines. This review describes the efficacy and potency of plant extracts/essences and probiotics as adjuvants for various vaccines in aquaculture.

Insect meals in fish nutrition - Silvia Nogales‐Mérida; Paola Gobbi; Damian Józefiak; Jan Mazurkiewicz; Krzysztof Dudek; Mateusz Rawski; Bartosz Kierończyk; Agata Józefiak (Reviews in Aquaculture, 2019)
Different studies have shown that insect meals can partially or completely replace the fish and soya bean meals that are commonly used in aquaculture. However, information is lacking on the amino acid and fatty acid contents and digestibility of different insect meals. Moreover, we evaluated different proportions of insect diets and determined how these affected the nutritional values of insect meals. Our purpose was to clarify these aspects and consider the availability of protein, amino acids, lipids and fatty acids in insect meals in fish nutrition. Generally, insect meals have higher indispensable amino acid contents than other meal types, with contents closely related to those in fish meal. Insect meal can be an important source of essential amino acids such as methionine, with contents ranging between 0.47 and 4.03 g 100 g −1 sample. These values are higher than those reported for other animal and plant meals. In addition, insects are also good sources of lipids and fatty acids, and the amounts and types of fatty acids vary according to the species, stage of development and type of feed. Moreover, the additional nutritional value of insect meal includes compounds such as chitin, which is primarily considered a fibre but also contains nitrogen and amino acids. Insect peptides with activity against pathogenic microflora provide secondary biological effects, which may significantly improve animal health.

Gender action plans in the aquaculture value chain: what's missing? - Roel H. Bosma; Thi Dien Nguyen; Lorna M. Calumpang; Sef Alba Carandang (Reviews in Aquaculture, 2019)
Gender equality has been a political issue in view of human rights and welfare since several decades. Therefore, many countries have developed Gender Action Plans (GAPs) that support equal access of both sexes to education, employment and finance. Two workshops on GAPs in aquaculture and a literature review brought about the question: what's missing in Asian sectoral GAPs. Not all reviewed Asian countries have GAPs for fishery/ aquaculture, but all encountered constraints to achieve their goals regarding equal access for women. Women's contribution in aquaculture tends to go beyond the traditional gender divide. For example, women may lead in the area of production because they can combine aquaculture with their homebound tasks and own vertically integrated companies. However, skewed perceptions on the role, status and perception of women and men, more so in strong than weak patriarchies (the former accept the subservient role, while the latter exercise the dominant role) limit women's access to training opportunities on new aquaculture technologies. Women are also left out in policy‐ and decision‐making processes; and in the value chain, women receive lower wages than men. Their role is underestimated by lack of disaggregated data, as reflected in post‐disaster interventions and industrial development programs. To be effective sectoral GAPs, based on disaggregated data, should have budgets, plans and target indicators for which leaders could be held accountable. These GAPs, however, can't address the required radical change in attitude toward women; unless deliberately planned educational media campaigns are embedded into the national GAPs.

The toolbox for protein digestion in decapod crustaceans: a review - María A. Navarrete del Toro; Fernando García‐Carreño (Reviews in Aquaculture, 2019)
Pancrustacea, including both crustaceans and insects, is the most abundant and diverse clade of Animalia and occupy all types of environments. They are studied because of their ecological, agricultural, health and economic issues, some being delicatessens. Crustaceans evolved during the Cambrian, thanks to adaptations, such as macrophagy, that allowed them to prey on diverse and energy‐rich foods, which depended on complex digestive systems that drove evolution. As heterotrophs, crustaceans depend on their ability to obtain nutrients to fulfil their material, mostly carbon and energy requirements. Protein is the most important nutrient; up to 70% dry mass of a crustacean is protein. Hence, food protein is needed to obtain free amino acids to synthesize protein de novo (from scratch), because animals cannot synthesize the ten essential amino acids de novo . The ability to digest protein must have emerged early in evolution, as shown by the finding of trypsin coding genes in eubacterial genomes. Primitive organisms selectively fixed the ability to use foreign protein as a source of amino acids by synthesizing enzymes, now termed peptidases, which were capable of recognizing and hydrolysing peptide bonds in a specific region of a polypeptide chain, based on specificity for the side chains of amino acid residues in the carboxylic side of the site of cleavage. Here, we present a brief history on what and how digestive peptidases in crustaceans became known.

Life cycle assessments of aquaculture systems: a critical review of reported findings with recommendations for policy and system development - Florence Alexia Bohnes; Michael Zwicky Hauschild; Jørgen Schlundt; Alexis Laurent (Reviews in Aquaculture, 2019)
The aquaculture sector is anticipated to be a keystone in food production systems in the coming decades. However, it is associated with potentially important environmental damages caused by its contribution to eutrophication or climate change, for example. To comprehensively quantify those impacts, life cycle assessment ( LCA ) studies have been conducted on several seafood farming systems for the past 15 years. But, what major findings and common trends can we draw from this pool of studies? What can we learn to provide recommendations to decision and policymakers in the aquaculture sector? To address these questions, we performed a critical review of 65 LCA studies of aquaculture systems from the open literature. We conducted quantitative analyses to explore which impacts can be identified as dominating and to compare different types of aquaculture systems. Our results evidenced that the feed production is a key driver for climate change, acidification, cumulative energy use and net primary production use, while the farming process is a key driver for eutrophication. We also found that different aquaculture systems and technology components may exert considerably different environmental impacts. Based on identified patterns and comparisons, we therefore provided specific recommendations to aquaculture stakeholders for future policy and system development. Overall, the analysis of existing studies demonstrates that important insights can be gained by applying LCA to aquaculture systems, and, to move towards an environmentally sustainable aquaculture sector, we recommend its systematic use in the design of new aquaculture systems or policies, and/or in the evaluation and optimization of existing ones.

Starch gelatinization on the physical characteristics of aquafeeds and subsequent implications to the productivity in farmed aquatic animals - Nicholas Romano; Vikas Kumar (Reviews in Aquaculture, 2019)
Starches are added macronutrients in aquafeeds to act as binders and provide inexpensive digestible energy to aquatic animals. These qualities can be further enhanced through gelatinization, which occurs when the crystalline region of amylopectin within the starch granule melts along with the leaching of amylose to form a gel matrix. This process readily occurs in the presence of heat and water, and therefore, some degree of starch gelatinization is ubiquitous in aquafeeds. When using simple technology, such as hand pelleters that employ less heat, pressure and shear forces, the inclusion of pre‐gelatinized starch can effectively improve pellet quality and digestibility in aquatic animals. In this review, the implications of starch gelatinization to various pellet characteristics will first be presented, followed by a brief discussion on carbohydrate metabolism in aquatic animals. A common feature of gelatinized starch in fish includes a higher digestibility; however, the implications to growth, physiology, post‐harvest quality as well as waste and disease management can depend on the host species, starch type and degree of gelatinization. This review comprehensively discusses these factors in various aquatic animals and such information may assist feed manufacturers and nutritionists to optimize cost‐effective feed formulations.

Generation, characterization, perniciousness, removal and reutilization of solids in aquaculture water: a review from the whole process perspective - Weijun Bao; Songming Zhu; Guang Jin; Zhangying Ye (Reviews in Aquaculture, 2019)
The generation of solids by aquaculture activities has led to many problems in animal welfare, environmental quality, water treatment effects and public health, such as gill and intestinal damage, water eutrophication, system components blockages and antibiotics transfers through the food chain to human; thus, effective solid wastes management is very important. The purpose of this review is to summarize the sources, characterization methods, harmfulness, removal technologies and reutilization of solids in aquaculture water, including (i) different sources of solids, such as uneaten feed, feces and debris; (ii) solids characterization based on the general parameters, particle size distribution and chemical composition; (iii) the toxicity and detriment of solids to cultured species, the environment, aquaculture system components and human health; (iv) Solids removal, effluents solids thickening and source control techniques for better solids management; and (v) various methods for the reutilization of aquacultural solid wastes for resource value‐adding. In addition to these five specific objectives, the merits and drawbacks of each method or technology and future research priorities are discussed. The present review provides an understanding of the role played by solids in aquaculture water and provides guidance for aquacultural solid wastes precision management, aquaculture practices and technological developments. Thus, solids management can be carried out based on this guidance to improve animal welfare and the stability of water treatment systems, reduce harm to the environment and public health, and enable the development of aquaculture in a sustainable way.

Use of models for the environmental risk assessment of veterinary medicines in European aquaculture: current situation and future perspectives - Andreu Rico; Marco Vighi; Paul J. Van den Brink; Mechteld ter Horst; Ailbhe Macken; Adam Lillicrap; Lynne Falconer; Trevor C. Telfer (Reviews in Aquaculture, 2019)
Veterinary Medicinal Products ( VMP s) are used in intensive aquaculture production to treat a wide range of bacterial and parasitic infestations. Their release into the environment poses concerns regarding their potential ecotoxicological risks to aquatic ecosystems, which need to be evaluated making use of appropriate Environmental Risk Assessment ( ERA ) schemes and models. This study presents an overview of the major aquaculture production systems in Europe, the VMP s most commonly used, and the environmental quality standards and regulatory procedures available for their ERA . Furthermore, it describes the state‐of‐the‐art on the development of environmental models capable of assessing the fate, exposure, ecotoxicological effects and risks of VMP s in aquaculture production systems, and discusses their level of development and implementation within European aquaculture. This study shows that the use of environmental models in regulatory ERA is somewhat limited in many European countries. Major efforts have been dedicated to assess the fate and exposure of antiparasitic compounds in salmonid cage systems, particularly in Scotland, while models and scenarios for assessing dispersal of antimicrobials, in general, and antiparasitic compounds in the Mediterranean as well as in Scandinavian regions are less available. On the other hand, the use of ecological models for assessing the effects and risks of VMP s is almost absent. Recommendations are provided to improve the chemical exposure and effect assessments and the ecological realism of the modelling outcomes, paying special attention to the protection goals set for the regulatory ERA of VMP s in Europe.

Artemia feeds: a review of brine shrimp production in the Mekong Delta, Vietnam - Tran Huu Le; Nguyen Van Hoa; Patrick Sorgeloos; Gilbert Van Stappen (Reviews in Aquaculture, 2019)
Seasonal Artemia pond production has been practiced for several decades by rural salt producing communities in the Mekong Delta, Vietnam, with more success than elsewhere in the world. In spite of this success, yields have been stagnating for a long time due to suboptimal feeding conditions. As feeding is one of the most important factors affecting Artemia production, the aim of this article was to review the studies that have been done so far on the development and application of appropriate Artemia feeds and feeding protocols in this area. So far, there are three main approaches. Traditionally, phytoplankton blooming is stimulated by the use of fertilizers in so‐called fertilization ponds. This green water is supplemented by the use of cheap agriculture waste products and chicken manure, directly applied in Artemia ponds. As this technique, however, often results in suboptimal feeding levels and comes with high nutrient charges in pond effluents, recently a formulated feed has been developed specifically for Artemia pond production which allows further increasing production levels. Finally, also the biofloc technology can be applied in Artemia culture by adding tapioca flour or molasses as carbon source to obtain the ratio C/N ≥ 10 in order to stimulate biofloc development as feed for Artemia in ponds. The limitations of the above techniques are discussed. It is envisaged that the future success and further expansion of Artemia pond production, also outside Vietnam, will increasingly be determined by a flexible use of a combination of these techniques.

Paraprobiotics: an aquaculture perspective - Tanmoy Gon Choudhury; Dibyendu Kamilya (Reviews in Aquaculture, 2019)
Probiotics, which are considered as live microbial adjunct conferring health benefits to the host, represent a potentially effective strategy for infectious disease control. Nevertheless, there has been growing concerns about safety, applicability and functionality issues associated with the live probiotic microorganisms. Concurrently, recent observations indicate that even the non‐viable counterparts of the probiotic organisms, also known as paraprobiotic, can be used to harness similar beneficial effects. Considering the limitations of probiotic application, paraprobiotics constitute a potential alternative strategy for improving health and wellness of fish and shellfish in aquaculture. Eventhough the concept of paraprobiotic is relatively established in higher vertebrate models and related food production sectors, its application in aquaculture is still in its early stage. In light of this, the present review delineates the concept of paraprobiotic, inactivation methods used for its preparation, the role of paraprobiotic in modifying biological responses as well as their potential application in aquaculture.

The complex interactions of Ostreid herpesvirus 1 , Vibrio bacteria, environment and host factors in mass mortality outbreaks of Crassostrea gigas - Andrea C. Alfaro; Thao V. Nguyen; Fabrice Merien (Reviews in Aquaculture, 2019)
From the first detection in the Eastern oysters ( Crassostrea virginica ) in 1972, herpes‐like viruses/herpesviruses have been identified in at least 20 bivalve species and have caused massive mortalities in six cultured species of bivalves. Among them, the Pacific oyster ( Crassostrea gigas ) is most threatened by massive mortalities associated with detection of Ostreid herpesvirus 1 (Os HV ‐1) and its variants. These mortality events have been reported in more than 12 countries, and Os HV ‐1 itself has been reported in 15 countries worldwide. Traditionally, the genotype Os HV ‐1 (or Os HV ‐1 Var) is the main contributor to bivalve mortalities, but the emergence of variants (e.g. Os HV ‐1 μVar and related ones, acute viral necrosis virus— AVNV , Os HV ‐1‐ SB ) is now responsible for new mortality outbreaks in Pacific oysters and other bivalve species. In addition to Os HV ‐1, Vibrio bacteria and other abiotic and host factors also significantly contribute to mortality outbreaks. To this end, the current contribution aims to synthesize the body of literature on our current knowledge of these mass mortality events to provide insights into the role of each risk factor and complex interactions in the disease process. Specifically, this review encompasses our current knowledge and critical gaps. Important suggestions for future investigation are also presented.

Salmon lice treatments and salmon mortality in Norwegian aquaculture: a review - Kathy Overton; Tim Dempster; Frode Oppedal; Tore S. Kristiansen; Kristine Gismervik; Lars H. Stien (Reviews in Aquaculture, 2019)
With the expansion of Atlantic salmon aquaculture, the economic and ecological impacts of salmon lice ( Lepeophtheirus salmonis ) has increased. Norway battles this problematic parasite with various control and preventative methods within farms. We analysed two national‐level databases to examine the number of operations reported each year from 2012 to 2017 and salmon mortality rates attributable to each operation type. From 2012 to 2017, 1.4 times more operations were registered, despite only limited increases in biomass produced across this period. We detected a rapid and recent paradigm shift in the industry's approach to lice control from chemotherapeutant to non‐medicinal operations. Chemotherapeutants (azamethiphos, cypermethrin, deltamethrin and hydrogen peroxide) dominated operations from 2012 to 2015 (>81%), while mechanical and thermal treatments dominated in 2016 and 2017 (>40% and >74%, respectively). Thermal operations caused greatest mortality increases (elevated mortality for 31% of treatments), followed by mechanical (25%), hydrogen peroxide (21%), and azamethiphos, cypermethrin and deltamethrin (

The importance of behaviour in improving the production of shrimp in aquaculture - Guillermo Bardera; Nafiha Usman; Matthew Owen; Daniel Pountney; Katherine A. Sloman; Mhairi E. Alexander (Reviews in Aquaculture, 2019)
There is an increasing recognition within the aquaculture industry that understanding the behaviour of farmed animals can help provide solutions to feeding problems. However, most studies have focused on finfish production, with fewer behavioural studies on feeding processes in commercially produced crustaceans. More than 60% of crustacean aquaculture is attributed to the production of penaeids, particularly the Pacific white‐leg shrimp ( Litopenaeus vannamei Boone). The profitability of the Pacific white‐leg shrimp for aquaculture stems from its ability to survive in a wide range of environments and its fast growth at high densities. However, there are significant setbacks within their farming. In particular, while they can move rapidly to take food pellets, they can be slow to consume them leading to food wastage and subsequent economic losses for the industry. Understanding shrimp behaviour provides a starting point for refinements to feeding practices. Here, we review the different influences on shrimp behaviour which are likely to influence productivity such as individual‐level effects (e.g. moulting, sex), environmental influences (e.g. photoperiod, conspecific presence) and water quality (e.g. salinity, temperature). Although work on feed management has been conducted, providing information on nutrition, feeding frequency and schedules, here we demonstrate that such advances must be accompanied by behavioural approaches to allow the development of optimal feeding efficiencies and to support the continued growth of the crustacean aquaculture industry.

Comparative toxic effects of copper‐based nanoparticles and their microparticles in Daphnia magna by using natural freshwater media - Francisca Arratia; Pamela Olivares‐Ferretti; Alba García‐Rodríguez; Ricard Marcos; Erico R. Carmona (New Zealand Journal of Marine and Freshwater Research, 2019)
Copper‐based nanoparticles (NPs) are being widely used in different application fields and their health impacts to aquatic environments represent a current concern. Few studies are available about their comparative toxicity with their bulks and ions under natural exposition in aquatic organisms. Thus, the toxicity of Cu and CuO NPs and their microparticle and ionic forms was assayed in the acute immobilisation test of Daphnia magna by using freshwater media. Electronic microscopy, laser doppler velocimetry, and dynamic laser scattering methodologies were used to NPs characterisation. The results indicated that CuNPs and CuONPs were more toxic than their microparticles. Among NPs, CuNPs showed higher toxicity than CuONPs. Copper‐based nanoparticles showed similar hydrodynamic particle size and were agglomerated in culture media, suggesting toxic‐ionic release relationship and corroborated by the high toxicity induced by CuSO 4 . Additionally, water chemistry of natural freshwater used in the experiments also favoured the ion release of these NPs.

Metazoan parasite communities of Selar crumenophthalmus and Decapterus muroadsi (Pisces: Carangidae) from Mexican Pacific coasts - Yesenia Gallegos‐Navarro; Juan Violante‐González; Scott Monks; Sergio García‐Ibáñez; Agustín A. Rojas‐Herrera; José Luis Rosas‐Acevedo (New Zealand Journal of Marine and Freshwater Research, 2019)
Metazoan parasites communities of marine fishes can include both adults and larval stages of several endoparasite groups that use fishes as intermediate or paratenic hosts. The richness and abundance of parasite species larvae that harbour a fish species can therefore be a good indicator of that species’ role as an intermediate host to endoparasite species. The parasite communities of two small carangid fishes ( Selar crumenophthalmus and Decapterus muroadsi ) from Mexican Pacific coasts were quantified and analysed. Five hundred sixty‐three carangids ( S. crumenophthalmus , n = 402; and D. muroadsi , n = 161) were collected between April 2014 and April 2018 from three locations. Twenty‐four metazoan parasite species were identified in both hosts: five species of Monogenea (adults), eight of Digenea (7 adults and 1 metacercaria), two of Cestoda (larvae), two of Nematoda (one adult and one larva), two of Acanthocephala (adults), and five of Copepoda. Larval helminths numerically dominated the endoparasite communities of both hosts, suggesting that these carangids are important intermediate hosts for several parasite species. Component parasite community richness and species composition differed between hosts, locations, and sampling years. Variations in host feeding behaviour, and body size were considered as important factors influencing these differences.

Predicting spatial patterns in riverbank erosion for catchment sediment budgets - Hugh G. Smith; Raphael Spiekermann; John Dymond; Les Basher (New Zealand Journal of Marine and Freshwater Research, 2019)
Riverbank erosion is an important component of catchment sediment budget models but remains one of the least well‐understood processes, particularly at large spatial scales. Here, we develop and test a new bank migration model in New Zealand for large catchment applications that (1) better represents spatial variability in factors influencing bank erosion and (2) improves predictive performance. We represent bank migration rates as a function of reach‐scale stream power, channel sinuosity, soil texture, valley confinement, riparian woody vegetation and channel protection works. The new model significantly improves prediction compared to the SedNetNZ model. Comparison of measured bank migration rates with individual variables shows percent silt + clay derived from soil maps exhibited the strongest correlation, whereas other variables were non‐significant. The model results demonstrate that improved prediction can be achieved by combining spatial representation of multiple factors over large areas, despite low correlation between individual variables and bank migration rates.

Ocean temperature change around New Zealand over the last 36 years - Philip J. H. Sutton; Melissa Bowen (New Zealand Journal of Marine and Freshwater Research, 2019)
Ocean temperature changes around New Zealand are estimated from satellite sea surface temperature (SST) products since 1981, two high resolution expendable bathythermograph transects (HRXBT) since 1986 and 1991, and Argo data since 2006. The datasets agree well where they overlap. Significant surface warming is found in subtropical waters. Greatest warming is east of Australia and in the central Pacific. All NZ coastal waters are warming, with strongest warming east of Wairarapa and weakest between East Cape and North Cape. Temperature changes are surface intensified, extending to ∼200 m in the northeast and at least 850 m in the eastern Tasman. Significant interannual variability is coherent over a large area of ocean north of the Subtropical Front and modulates extreme events. NZ air temperatures are highly correlated at interannual timescales with SSTs over a broad region of ocean north of the Subtropical Front from the eastern Tasman to east of the dateline.

CPOD successful in trial for detecting Māui dolphin outside harbours - Andrew J. Wright; Nick Tregenza (New Zealand Journal of Marine and Freshwater Research, 2019)
Critically endangered Māui dolphin ( Cephalorhynchus hectori maui ) are found exclusively off the west coast of New Zealand’s North Island. One important data gap troubling efforts to reduce the current unsustainable level of bycatch is the limited information on the offshore and alongshore limits of their range. Passive acoustic monitoring studies could address this data gap, but Māui dolphin habitat is dominated by a sandy substrate that can shift greatly in the strong local currents. In February 2016, a short pilot CPOD deployment was thus attempted as a first step to see if the equipment could be deployed and recovered in the area and if the data collected would be viable, with a second unit deployed inside a harbour for comparison with earlier TPOD data. The pilot was largely successful, and roughly 11% of all minutes in the core habitat location contained detections of clicks attributed to Māui dolphin. A visual inspection of the data suggests some trends with diel and tidal patterns. Further work of this type is thus recommended.

Faecal indicator bacteria in New Zealand freshwater fish: a pilot study - Sarah Coxon; Jon S Harding; Brent Gilpin (New Zealand Journal of Marine and Freshwater Research, 2019)
Recent studies have suggested that poikilothermic animals, such as fish, may represent a previously overlooked source of the faecal indicator bacteria (FIB) used for the assessment of water quality. However, quantitative studies of FIB in poikilotherms are scarce. We investigated the presence of FIB in the faeces of five freshwater fish species. E. coli and enterococci were detected in 71 and 76% of faecal samples, respectively. Concentrations were highly variable, with maximum concentrations (2.1 × 10 4 E. coli and 1.3 × 10 6 enterococci per gram of faecal material) up to four orders of magnitude higher than present in the water column. FIB were not detected in faecal samples from marine fish. Our findings suggest that FIB ingested from the environment may be capable of replication within the fish gut, making fish a potential source and transport mechanism for FIB in New Zealand freshwaters. This may have implications for water quality monitoring.

Plankton: A guide to their ecology and monitoring for water quality, 2nd edition - Miles Lamare (New Zealand Journal of Marine and Freshwater Research, 2019)

Echyridella menziesii (Bivalvia: Hyriidae) as a predator of zooplankton of different sizes; are large non‐indigenous Daphnia a potential food source? - Anita A. C. Pearson; Ian C. Duggan (New Zealand Journal of Marine and Freshwater Research, 2019)
Interactions between two recent invaders to New Zealand, the cladocerans Daphnia galeata and D. pulex , and native filter‐feeding freshwater mussels, are unknown. We examined predation rates of the common native mussel Echyridella menziesii (kākahi, kāeo) on non‐native Daphnia (comparatively large zooplankton in New Zealand), relative to two common native species, the smaller cladoceran Bosmina meridionalis and rotifer Brachionus calyciflorus . Controlled laboratory experiments were conducted in which each zooplankton species was exposed to bivalve predation for a two‐hour period. Comparing treatments to non‐mussel controls, removal rates of non‐indigenous D . pulex and native B . calyciflorus were statistically significant. Nevertheless, kākahi removal rates may not be ecologically significant for daphnids (1.7% D . galeata and 7.4% D. pulex ). Kākahi removed 8.8% of B. meridionalis and 30.2% of B. calyciflorus , suggesting that small, feeble zooplankton species (particularly rotifers) are most susceptible to predation, and potentially function as an energy source for native freshwater mussels.

Effects of sediment deposition on the New Zealand cockle, Austrovenus stutchburyi - Tara Anderson; Henry Barrett; Don Morrisey (New Zealand Journal of Marine and Freshwater Research, 2019)
New Zealand estuaries and harbours are subjected to increasing sediment deposition that can smother and bury infaunal communities, yet how coastal species respond to sediment deposition is not well understood. Here, we experimentally examined the effects of native marine sediment deposition on the NZ cockle ( Austrovenus stutchburyi ). Cockles were found to be highly mobile and capable burrowers, able to resurface within days from beneath 2–25 cm of sediment where no physical disturbance to their natural orientation occurred. Cockles were also resilient to daily (2 cm) reburials. However, following disturbance to their natural orientation, inverted cockles were significantly impeded when buried under 5–10 cm of sediment, with fewer adults resurfacing than sub‐adults. Cockle populations are likely to be resilient to native sediment deposition, unless physically disturbed. When disturbed from their natural orientation in the sediment, higher mortality of larger adult‐sized cockles would be predicted, with mortality increasing under thicker sediment deposits.

Lamprey ( Geotria australis ; Agnatha) reddening syndrome in Southland rivers, New Zealand 2011–2013: laboratory findings and epidemiology, including the incidental detection of an atypical Aeromonas salmonicida - Cara L. Brosnahan; Anjali Pande; Suzanne E. Keeling; Mary van Andel; John B. Jones (New Zealand Journal of Marine and Freshwater Research, 2019)
From 2011, lamprey ( Geotria australis ) populations in Southland, New Zealand have been affected by reddening along the length of the body and increased mortalities, termed lamprey reddening syndrome (LRS). Molecular testing, bacteriology, histopathology and epidemiology were used to determine if an infectious agent was present and to increase the understanding of this syndrome. An atypical Aeromonas salmonicida was detected from affected lamprey in 2011. This organism has not previously been reported from New Zealand. Investigative molecular testing indicated the organism was an uncharacterised, unculturable, atypical A. salmonicida and a likely incidental finding. Histopathology did not indicate an infectious process was involved, but suggested the reddening may be due to blunt trauma. Epidemiological investigation found the Mokoreta River had a significantly higher prevalence of LRS than others in the Southland region, but there was no clear reason why. To date, no infectious aetiology for this syndrome has been identified.

Reproducibility of river water quality measurements: inter‐agency comparisons for quality assurance - Rob Davies‐Colley; Juliet Milne; Mark W. Heath (New Zealand Journal of Marine and Freshwater Research, 2019)
We assessed the reproducibility of river state‐of‐environment (SoE) water quality measurements in the Wellington Region, New Zealand (NZ). Field staff from GWRC and NIWA conducted 29 side‐by‐side water sampling and in‐situ measurements at six river sites of diverse water quality for 12 variables measured routinely in river SoE monitoring across NZ. Field measurements of water temperature, dissolved oxygen, electrical conductivity and visual clarity agreed closely with strong numerical similarity (within 10%). Numerical similarity ranged widely for laboratory measurements, from strong for nitrate‐nitrite‐nitrogen to weak for turbidity, dissolved reactive phosphorus, and ammoniacal‐nitrogen. Numerical agreement was very weak for laboratory pH (which is problematic) and E. coli –which is ‘tolerable’ for many applications given good correlation ( R = 0.94) over a 2000‐fold concentration range. The findings of our inter‐agency comparison have contributed to quality assurance recommendations in the NZ National Environmental Monitoring Standard (NEMS) for water quality.

Fish community responses to invasive fish removal and installation of an exclusion barrier at Lake Ohinewai, Waikato - Grant W. Tempero; Brendan J. Hicks; Nicholas Ling; Dai Morgan; Adam J. Daniel; Deniz Özkundakci; Bruno David (New Zealand Journal of Marine and Freshwater Research, 2019)
Introduced common carp ( Cyprinus carpio ) are a recognised threat to New Zealand’s freshwater ecosystems. In 2011, an invasive fish removal programme was undertaken in 16.8 ha Lake Ohinewai, a Waikato riverine lake. Active fish removal using netting and boat electrofishing was supported by installation of a one‐way exclusion barrier on the outflow to Lake Ohinewai. The barrier was designed to allow fish passage downstream out of the lake, while preventing adult carp from moving upstream. The estimated carp population was reduced from 8,548 fish (5,863–12,937, 95% confidence limits) in 2011–454 fish (251–889, 95% CL) in 2014. However, by 2016 the carp population had recovered to 2,063 fish (1,070–4,328, 95% CL) with increased abundance in invasive brown bullhead catfish ( Ameiurus nebulosus ) also observed. This research demonstrates that carp populations can be reduced to low abundances in the short to medium term, but continued removal will be required for on‐going control.

Chinese Abstracts (Reviews in Aquaculture, 2019)

Issue Information (Reviews in Aquaculture, 2019)

Male morphotypes and alternative mating tactics in freshwater prawns of the genus Macrobrachium : a review - Ilan Karplus; Assaf Barki (Reviews in Aquaculture, 2019)
The discontinuous variation in male mating behaviour is termed alternative mating tactics. A distinction is commonly made between alternative mating tactics that are fixed for life or flexible with simultaneous or sequential switches between tactics over the sexually mature life. Freshwater species of the genus Macrobrachium demonstrate flexible tactics with sequential (i.e. developmental) switch between tactics. Sexually mature populations of the commercially important giant freshwater prawn M. rosenbergii consist of three morphologically and behaviourally distinct male morphotypes: small males, orange claw and blue claw males, representing (respectively) successive stages in the developmental pathway of sexually mature males. The dominant blue claw males secure mating by guarding receptive soft‐shelled females with their long chelipeds while the subordinate SM use an alternative tactic of sneak mating to fertilize females. Current knowledge of the mating behaviour and reproductive success of these male morphotypes, including male competition over females, female mate choice and the involvement of pheromones, is reviewed. So far, the occurrence of distinct sexually mature male morphotypes has been described in 24 species within the genus Macrobrachium . The prevalence of distinct male morphotypes and alternative mating tactics among Macrobrachium species is discussed in view of the phylogeny of the genus, based on molecular markers. The environmental and genetic determination of the male morphotypes is discussed, as well as the evolution of the developmental alternative mating tactics in the genus Macrobrachium . Possible implications for prawns’ aquaculture and future research are suggested.

Advancing assessment of marine phytoplankton community structure and nutritional value from fatty acid profiles of cultured microalgae - José P. Cañavate (Reviews in Aquaculture, 2019)
The dual function of fatty acids as both biomarkers of phytoplankton community structure and proxies of their nutritional value is becoming increasingly recognized as a substantial complement to elemental stoichiometry studies in aquatic ecology and aquaculture. Despite information on fatty acid composition of marine microalgae being more abundant, phytoplankton fatty acid reviews as well as information on their nutritional quality and effects in food webs are far more frequent for freshwater species. Here, 683 fatty acid profiles of 115 genera of marine microalgae belonging to 17 classes from eight phyla and cultured under nonstressful conditions were compiled. Data analysis allowed establishment of fatty acid reference values that can be used to quantitatively determine marine phytoplankton community structure with an unprecedented descriptive level. Fatty acids also served to generate the first microalgae nutritional index adapted to requirements of consumers and their trophic upgrading capabilities. Fatty acid profile allowed taxonomically differentiating among marine microalgae within a group comprising 14 classes and the Bacillariophyta phylum. Phylogeny was the strongest driving force of fatty acid variation, whereas the marine or freshwater origin of microalgae contributed

Applications of plant ingredients for tropical and subtropical freshwater finfish: possibilities and challenges - Koushik Ghosh; Arun K. Ray; Einar Ringø (Reviews in Aquaculture, 2019)
The demand for cultured finfish has increased tremendously during the last decades, but the success of intensive farming is dependent on several factors, namely management, dietary supplementations and welfare. During the last decades, increasing demand, high price and limited supply of fishmeal have emphasized the need for alternative protein sources in aquafeeds, but plant proteins possess a series of endogenous antinutritional factors ( ANF s; e.g. protease inhibitors, tannin, mimosine, phytic acid, nonstarch polysaccharides), and they must be destroyed or inactivated. Inclusion of alternative protein sources has resulted in production losses and is a concern for farmers. However, the problem with ANF s might be solved using advanced processing techniques. The present review, focusing on tropical and subtropical freshwater finfish, will discuss findings on applications of conventional methods, as well as fermentation technology for deactivation of endogenous ANF s, and the use of probiotics with ANF degrading potential when plant ingredients are included in fish feeds.

A literature review as an aid to identify strategies for mitigating ostreid herpesvirus 1 in Crassostrea gigas hatchery and nursery systems - Chris Rodgers; Isabelle Arzul; Noèlia Carrasco; Dolores Furones Nozal (Reviews in Aquaculture, 2019)
An understanding of husbandry strategies and any associated risk factors is important for designing management control measures that can reduce mortality in Pacific oysters, Crassostrea gigas , caused by ostreid herpesvirus 1 (Os HV ‐1). The type of culture facility can be considered in relation to the potential pathways that could lead to the entry of a pathogen and its survival. In addition, the animal host (e.g. age, physiological state, selective breeding programmes), husbandry procedures (e.g. stocking density), the pathogen itself (e.g. pathogenicity, virulence) and environmental effects (e.g. temperature) represent other relevant interconnected factors. However, all these factors provide valuable background information for outlining the mitigation strategies needed by the industry, as well as in the context of surveillance and biosecurity programmes. These control mechanisms for hatchery or nursery areas are related to movement restrictions, water treatment, virus inactivation, the production calendar and practical farm management decisions. This comprehensive literature review compiles information related to such approaches and also includes the different existing guidelines suggested for control of Os HV ‐1. Therefore, the review represents a solid foundation for a more critical appraisal currently being developed to support recommendations for disease management strategies.

Macroalgae as a sustainable aquafeed ingredient - Alex H.L. Wan; Simon J. Davies; Anna Soler‐Vila; Richard Fitzgerald; Mark P. Johnson (Reviews in Aquaculture, 2019)
Macroalgae, commonly known as seaweed, offer a novel and added‐value dietary ingredient in formulated diets for fish. Production of biomass can be achieved without reliance on expensive arable land, as seaweed may be collected from coastal regions or farmed. There are three taxonomic groups represented by the term ‘macroalgae’: Rhodophyta (red), Chlorophyta (green) and Phaeophyta (brown). Like terrestrial plants, nutritional content in macroalgae can vary greatly amongst species, genera, divisions, seasons and locations. Aside from their basic nutritional value, seaweeds contain a number of pigments, defensive and storage compounds, and secondary metabolites that could have beneficial effects on farmed fish. This review appraises the beneficial qualities of these macroalgae compounds and their potential for exploitation in commercial finfish feeds. The current knowledge of the effects of macroalgae inclusion in finfish diets is also addressed. From these >50 fish feeding studies that were analysed, enhancing trends in fish growth, physiology, stress resistance, immune system and fillet muscle quality were reported. However, only a small fraction of algal species have so far been investigated as potential components in finfish diets, and furthermore, this review has identified a number of knowledge gaps that current research has yet to address. To conclude, an appraisal is made of the possible technologies employed to exploit seaweeds to an industrial level through stabilising the algal meal, enhancing the digestibility and functional food properties.

Probiotic application for sustainable aquaculture - Mahmoud A.O. Dawood; Shunsuke Koshio; Mohamed M. Abdel‐Daim; Hien Van Doan (Reviews in Aquaculture, 2019)
Aquaculture, which constitutes one of the largest food production sectors in the world, is preferably practiced with natural organic products rather than with synthetic chemicals or antibiotics. In addition to the daunting challenge of providing food and livelihood to the exponentially increasing world population, the aquaculture industry is key to ensuring that development is based on environmentally sustainable practices, specifically in the production of aquafeeds. Terrestrial microorganisms that act as natural defence systems of cultured species have been identified as the main producer for the beneficial bacterial candidates. Probiotics have recently gained popularity as beneficial microbes candidates in cultured organisms to maintain the health condition and well‐being of different aquatic animals. This review aimed to understand the necessity of using probiotics as a sustainable alternative to regulate the growth performance, feed utilisation and general health condition for sustainable aquaculture. Also, explanatory discussion about the host microbiota and its ability to produce different probiotic strains and the probiotic functionality to ameliorate the host immunity to provide the interactive effects on the host‐derived probiotics. By presenting the results obtained from the previous studies about the ability of probiotics to sustain the aquatic animal's performances, this study condensed the current knowledge and information for future research and development of the probiotic application in aquaculture.

Fish sperm motility assessment as a tool for aquaculture research: a historical approach - Victor Gallego; Juan F. Asturiano (Reviews in Aquaculture, 2019)
Fish sperm motility is nowadays considered the best biomarker for the quality of fish spermatozoa, and sperm motion parameters from more than 300 fish species have been reported in more than 1500 scientific articles covering a wide range of topics, from molecular biology to ecology. The most studied topics have been (i) the sperm storage (involving both the use of chilled‐storage protocols for short‐term periods and sperm cryopreservation techniques for long‐term storage), (ii) the sperm physiology (fathom in the spermatozoa activation process and the whole propulsion machinery of the sperm cells) and (iii) the broodstock management (covering aspects such as rearing conditions, dietary requirements or hormonal induction treatments). In addition, other aquaculture and ecological topics, such as (iv) the knowledge of the breeding cycle of the species, (v) the phenomenon of the sperm competition and (vi) ecotoxicological studies for the evaluation of aquatic environments, have also been approached from the evaluation of sperm motion performance. Therefore, fish sperm motility assessment can serve as a potential tool for aquaculture and ecological purposes, covering key topics of fundamental and applied research. This review gives an overview of the major research areas in which fish sperm motility has been applied successfully.

Encapsulation for delivering bioactives in aquaculture - Seyedehsara Masoomi Dezfooli; Noemi Gutierrez‐Maddox; Andrea Alfaro; Ali Seyfoddin (Reviews in Aquaculture, 2019)
The exploitation of wild fisheries has driven the seafood industry to develop more sustainable resources and high‐intensity aquaculture. However, high‐density aquaculture is prone to outbreaks of diseases. The use of chemicals and antimicrobial drugs in aquaculture is common practice, but such chemicals can have serious detrimental environmental impacts and antibiotics may result in bacterial resistance in many species. The development of non‐antibiotic and green strategies, such as using probiotics and immunostimulants, aims for a more sustainable practice for health maintenance in aquaculture. Although the efficacy of such strategies has been demonstrated in cultivations settings, the effective delivery of bioactives remains a challenge. Conventional delivery methods are often ineffective in terms of dosage, stability and species specificity, and can possibly cause widespread environmental contamination. However, recently developed drug delivery systems may provide innovative ways to improve delivery with minimal waste and improved environmental protection. Indeed, such cutting‐edge drug delivery systems have already provided measurable benefits in human medicine over the past two decades. New technologies, such as encapsulation and controlled release systems, can be used readily in scaled‐up operations to improve the delivery of bioactives and ultimately increase production and profitability in aquaculture. This review critically analyses the use of encapsulation technology with a focus on microparticles for delivery of bioactive agents to farmed aquatic animals. This review discusses various potential encapsulation materials, their properties and a range of methods that can be applied and scaled‐up for aquaculture. Finally, practical considerations for designing an efficient delivery system for aquaculture are discussed.

Mineral nutrition and bone health in salmonids - Grete Baeverfjord; P. Antony Jesu Prabhu; Per Gunnar Fjelldal; Sissel Albrektsen; Bjarne Hatlen; Vegard Denstadli; Elisabeth Ytteborg; Harald Takle; Erik‐Jan Lock; Marc H.G. Berntssen; Anne‐Katrine Lundebye; Torbjørn Åsgård; et al. (Reviews in Aquaculture, 2019)
In the recent years, challenges faced in salmonid farming with regard to deformities have helped to improve our knowledge on skeletal biology and development of bone health in salmonids. Different nutritional, genetic and environmental factors are associated with skeletal deformities in salmonids and other fish species. Minerals are a group of essential nutrients having a vital role to play in skeletal development, growth and remodelling. The knowledge generated thus far on the structural and functional importance of minerals in salmonid bone health is largely restricted to phosphorus. A brief account of dietary phosphorus‐related bone deformities encountered in salmonids, critical life stages for the development of bone deformities, recent developments in the understanding of their aetiology and dietary phosphorus levels required to improve bone health are presented. The effect of increased dietary level of phosphorus in reducing bone health disorders under conditions of improved feed conversion efficiency and use of triploids in salmon farming are illustrated with help of metadata analysis from literature. With regard to the role of other essential minerals (macro‐ and micro‐) impacting bone health in salmonids, data available are extremely limited and hence information on other fish species and mammals is summarized in relation to bone development and incidence of deformities. The need to improve mineral bioavailability, utilization and reduce effluent mineral load is presented in brief with example from Norwegian salmon farming. Refinements in mineral requirement recommendations for salmonids and advanced methodologies for studying aetiology of skeletal anomalies, bone mineral status, skeletal development and deformities are also discussed.

A critical review on control methods for harmful algal blooms - Juan J. Gallardo‐Rodríguez; Allisson Astuya‐Villalón; Alejandra Llanos‐Rivera; Veronica Avello‐Fontalba; Viviana Ulloa‐Jofré (Reviews in Aquaculture, 2019)
The impacts of harmful algal blooms on human health, tourism, fisheries and ecosystems have increased in recent decades. Eutrophication and the feared climate change are believed to further challenge authorities and those whose activity depends on coastal resources. While in most of the affected countries, regulatory steps have been taken to protect consumers of contaminated food, there has been an unequal focus on management systems. Some countries such as EEUU and Canada have focused on monitoring and prediction programs, whereas others (e.g. Korea, China) have relied on direct control of blooms in the sea. Here, we review current control methods for HAB s including their fundamentals and the last scientific advances. A thorough revision of all considered approaches so far has been included. Ecological studies of the impact of the countermeasures were also considered.

Economically viable aquaponics? Identifying the gap between potential and current uncertainties - Asael Greenfeld; Nir Becker; Jennifer McIlwain; Ravi Fotedar; Janet F. Bornman (Reviews in Aquaculture, 2019)
Aquaponics, which integrates hydroponic farming and aquaculture, has the potential for sustainably producing high‐quality food, but has yet to achieve commercial success. In recent years, however, commercial‐scale aquaponics has received considerable attention from the scientific community, with the current literature covering many aspects of aquaponic production. We reviewed this literature and classified the specific areas covered by each paper and its contribution to either cost reduction or benefit enhancement. The literature regarding the economic benefits of aquaponics was summarised, and despite contradicting views of current profitability, there is a consensus that (i) larger systems are economically superior to smaller ones; (ii) profitability is sensitive to retail prices; and (iii) commercial aquaponics are more profitable through improved business plans. This review provides a quantitative scientific analysis of the bioeconomics and potential of commercial aquaponics, useful for both researchers and practitioners. We argue for greater focus on three understudied aspects that could each be a ‘game changer’ for commercial aquaponics. These include the following: (i) grower considerations such as financial planning and risk management that affect potential growers’ initial engagement in aquaponics; (ii) consumer perception of aquaponic products including the willingness to pay more for its added value; and (iii) the economic value of the environmental benefits of aquaponic systems and ways to internalise them for profit. Further study of each of these aspects, along with the ongoing improvement of production systems, will support the establishment of large‐scale aquaponics as an economically sustainable industry.

Cellular and molecular changes associated with fish oocyte ageing - Azin Mohagheghi Samarin; Azadeh Mohagheghi Samarin; Tomas Policar (Reviews in Aquaculture, 2019)
Post‐ovulatory oocyte ageing in fish is associated with limited fertilization rate, poor embryo development, larval malformation, ploidy anomalies and various other offspring abnormalities. Many studies have focused on morphological, physiological, biochemical and histological changes that occur during oocyte ageing. However, little is known about molecular changes associated with this process. This review covers the cellular and molecular characteristics of ageing oocytes with special focus on age‐associated changes affected by oxidative damage. The contribution of oxidative stress and mitochondrial dysfunction, as well as new insights into oocyte ageing in higher vertebrates, is discussed to provide direction for future studies. Investigating the genomics and proteomics of oocyte ageing, including underlying molecular mechanisms, could contribute valuable information on determinants of egg quality. Such knowledge can be translated into practical applications in aquaculture, such as supplementation of oocyte culture media with antioxidants and other agents as a means to inhibit or delay development of the aged oocyte phenotype. Identification of cellular and molecular markers associated with the oocyte ageing process will benefit such developments.

US antidumping petitions and revealed comparative advantage of shrimp‐exporting countries - Chia‐Lin Chang; Michael McAleer; Dang‐Khoa Nguyen (Reviews in Aquaculture, 2019)
The paper explores the trade competitiveness of seven major shrimp‐exporting countries, namely Vietnam, China, Thailand, Ecuador, India, Indonesia and Mexico, to the United States. Specifically, we investigate whether the US antidumping petitions have an impact on the bilateral revealed comparative advantage ( RCA ) indexes for each of the seven shrimp‐exporting countries with the United States. Monthly data from January 2003 to December 2014 and a panel data model are used to examine the determinants of the RCA for the shrimp‐exporting countries. The empirical results show the shrimp‐exporting countries have superior competitiveness against the shrimp market in the United States. Moreover, the RCA indexes are significantly negatively influenced by shrimp prices, and are positively affected by US income per capita. However, the EMS (Early Mortality Syndrome) shrimp disease, domestic US shrimp quantity, exchange rates and US antidumping laws are found to have no significant impacts on the RCA indexes. In terms of policy implications, the United States should try to reduce production costs of shrimp in the US market instead of imposing antidumping petitions. Moreover, the shrimp‐exporting countries should try to maintain their comparative advantage and diversify into new markets.

Hydrodynamic effects on oyster aquaculture systems: a review - Matthew D. Campbell; Steven G. Hall (Reviews in Aquaculture, 2019)
Hydrodynamics (i.e. interactions of fluid motion with solid bodies) affect oyster aquaculture within every phase of farming. Although it has many direct and indirect implications to the success of any particular aquaculture endeavour, hydrodynamics is the least understood of environmental factors affecting oyster growth. As the industry continues to mature, it is imperative that the influence of hydrodynamics on oyster aquaculture is thoroughly understood. Hydrodynamics also interacts with other environmental factors, such as salinity, temperature, turbidity, food supply and oxygen, which affect the health and growth of oysters through mixing and transport. Proper siting and management of aquaculture requires a comprehensive understanding of the hydrodynamics involved and its impact on the culture of oysters. Unfortunately, literature is inconsistent on oyster feeding and growth response to the influence of hydrodynamics. Feeding and growth limiting velocities are reported that range from 1 to above 22 cm s −1 . This is in contrast with thriving oyster reefs in a natural setting that exist and thrive above 15 cm s −1 . Upweller systems have reported bulk velocities that range from 0.5 to 7.1 cm s −1 . In practice, higher current velocities are desirable because they increase delivery of food to the oysters, improve water quality, and enhance dispersal of biodeposits. This paper summarizes the findings of those studies in regard to hydrodynamics and provides suggestions for future work.

Bioeconomic modelling of the intensive production of white‐leg shrimp ( Litopenaeus vannamei ) in a photo‐heterotrophic hypersaline system, with minimal seawater replacement - Luis Daniel Moreno‐Figueroa; Humberto Villarreal‐Colmenares; José Naranjo‐Páramo; Mayra Vargas‐Mendieta; Laurence Mercier; Ramón Casillas‐Hernández; Alfredo Hernández‐Llamas (Reviews in Aquaculture, 2019)
We use a bioeconomic approach to analyse the production, and economic performance of shrimp ( Litopenaeus vannamei ) reared in a photo‐heterotrophic, hypersaline intensive system with minimal water replacement during spring‐summer ( SS ) and summer‐autumn ( SA ) production cycles in the semiarid region of Baja California Sur, Mexico. Salinity was maintained at 45 ± 2.0 ( SS ) and 46 ± 2.5 g L −1 ( SA ), dissolved oxygen at 4.8 ± 0.5 ( SS ) and 4.4 ± 0.4 mg L −1 ( SA ), pH at 7.9 ± 0.3 ( SS ) and 7.8 ± 0.2 ( SA ), and temperature at 28.4 ± 2.4 ( SS ) and 31.6 ± 0.7°C ( SA ). The bioeconomic analysis indicated that the mean production in SS is 13.2 t ha −1 , and that mean net revenues of 12 600 $USD ha −1 and a benefit‐cost ratio of 1.31 could be obtained. For SA , mean production was 17.7 t ha −1 , and mean net revenue and the benefit‐cost ratio were 38 930 $USD ha −1 and 1.93, respectively. The optimum harvesting times were at 90 ( SS ) and 92 days ( SA ) when the economic indicators and the confidence of obtaining them were maximized. Superior economic performance of SA was a consequence of faster shrimp growth and higher shrimp prices. More stable conditions of water quality resulted in better production in SA . A sensitivity analysis showed that shrimp price was the most important factor influencing net revenue, and that final weight of shrimp, dissolved oxygen and temperature had intermediate influence. Positive economic outcomes indicate the potential of the photo‐heterotrophic technology for shrimp production in semiarid regions.

Meta‐analysis on nutrition studies modulating sea urchin roe growth, colour and taste - Sílvia Lourenço; Luísa M.P. Valente; Carlos Andrade (Reviews in Aquaculture, 2019)
Sea urchin roe is highly appreciated worldwide as a gourmet product comparable to caviar. Research in echinoculture mainly focus on the production of high‐quality roe which stands for large golden orange to yellow gonads with a distinct, sweet ocean taste known as uni . The scientific approaches to manipulate roe quality are diverse in terms of targeted species and manipulated factors as nutrition, environmental and husbandry conditions. In this study, a meta‐analysis approach was applied to systematically review the research conducted between 2000 and 2017 aiming to enhance the sea urchin roe quality. The 48 studies selected and analysed here show that those targeting the growth of gonads were successful, independently of the selected species, the rearing system adopted, or the diet or nutrient tested. In contrast, most trials focusing on colour manipulation resulted in roe colour similar to the control group (sea urchins fed with algae). Only six studies aiming to enhance roe taste were selected but described inconclusive results. In conclusion, while the production of large gonads seems easily achievable, the enhancement of its colour and taste is still a challenge.

Advances in the use of alternative protein sources for tilapia feeding - Nathaly Montoya‐Camacho; Enrique Marquez‐Ríos; Francisco Javier Castillo‐Yáñez; José Luis Cárdenas López; José Antonio López‐Elías; Saúl Ruíz‐Cruz; Edgar Iván Jiménez‐Ruíz; Martha Elisa Rivas‐Vega; Víctor Manuel Ocaño‐Higuera (Reviews in Aquaculture, 2019)
The raising demand of fish for human consumption has caused a rise in fish cultivation to become a more intense activity and has increased the need for fish feed formulas for aquaculture. Tilapia are aquatic organisms with moderate protein requirements. One of the traditional ingredients used to develop protein diets is fish meal. Despite its high cost, this supply is of high demand for both aquaculture and terrestrial animals. Efforts to seek for alternative sources of conventional and unconventional proteins are ongoing. The purpose of this study is to review alternative sources of proteins with potential to partially or fully substitute fish meal in tilapia feed. Also, it addresses the challenges that aquaculture feeding is facing regarding the substitution of fish meal with proteins from plant sources.

Seeking the perfect oyster shell: a brief review of current knowledge - Darien Danielle Mizuta; Gary H. Wikfors (Reviews in Aquaculture, 2019)
Current trends in the seafood market indicate increased demand for within‐shell oysters, associated with increasing popularity of oyster bars. As this specialized, demanding market increases globally, there is strong incentive to improve quality. In this context, the manipulation of oyster shell traits through aquaculture as a means of improving oyster quality is timely and promising in terms of marketing. Several oyster shell characteristics, most especially shape, measured as length (L), width (W) and depth (D), result from a combination of three factors: genetics, environmental condition to which the oyster is exposed and husbandry practices. Although breeding programmes have targeted several important commercial traits, selection for shell traits has not been widely performed. Additionally, accumulated knowledge of the effects of environmental conditions and farming methods on shell characteristics exists at a local level, but as such, it is not always validated with scientific data. The existing local knowledge and practices, however, are of extreme importance for the improvement and adaptation of the farming sector to market demands. Current knowledge about the genetic, environmental and husbandry effects on shell and related aquaculture practices for manipulation of shell appearance and robustness in commercially important oysters of the Genus Crassostrea is compiled here. As the topic has not been well documented in the academic field, information from scientific articles was complemented by technical reports and commercial sources. A combination of aquaculture practices is needed to produce oysters of acceptable shape, thickness, cleanliness and colour, although suitable shell characteristics may vary with different markets.

A review on the research status and development trend of equipment in water treatment processes of recirculating aquaculture systems - Ruichao Xiao; Yaoguang Wei; Dong An; Daoliang Li; Xuxiang Ta; Yinghao Wu; Qin Ren (Reviews in Aquaculture, 2019)
Recirculating aquaculture systems ( RAS s) are intensive aquaculture facilities models that depend on diverse water treatment equipment to maintain good water quality and produce safe and healthy high‐quality aquatic products. This article combines the main farming‐mode of water purification recirculating processes with recent cultivation‐mode scientific research and the current development of the recirculating aquaculture industry. Harmful substances are present in aquaculture wastewater due to large quantities of residual particulate matter such as residual feed, faeces and small suspended solid particles, as well as ammonia, nitrite, bacteria and carbon dioxide ( CO 2 ), in the water. These harmful substances seriously affect the quality of aquatic products, so water treatment equipment is needed to remove these substances, add oxygen (O 2 ) to the water and adjust the temperature of the water to ensure a high‐quality environment for fish survival. This article reviews the equipment for physical filtration (e.g. solid–liquid separation equipment, microscreen drum filter and foam fractionator) that could remove suspended solids during the water treatment of RAS s and the equipment for biological filtration (e.g. fluidized sand biofilter ( FSB ), moving‐bed biofilm reactor ( MBBR ) and rotating biological contactor ( RBC )) that could remove ammonia nitrogen, nitrite and other hazardous substances from wastewater, as well as equipment for water disinfection and sterilization, O 2 addition, CO 2 removal and temperature control. Comprehensive analysis and discussion of water treatment efficiency are provided for reference to create efficient high‐end recirculation aquaculture models and increase the precision and intelligence degree of recirculating water treatment technologies in the future.

Cultivation of native fish in Mexico: cases of success - Claudia Araceli Dávila‐Camacho; Itzel Galaviz‐Villa; Fabiola Lango‐Reynoso; María del Refugio Castañeda‐Chávez; Cecilia Quiroga‐Brahms; Jesús Montoya‐Mendoza (Reviews in Aquaculture, 2019)
Aquaculture practice in Mexico is commonly carried out with some freshwater species, which are introduced in the region for its production, with technology developed in other countries. The growth of this activity has been slow, sometimes leading to loss of investments due to difficulties in the implementation of foreign technological packages, poor selection and inadequate management of the species, or farming sites, and even confusing legal procedures. Mexico stands out for the development of crops of exotic species more than native species, of which most are freshwater type. There are thirty‐four recorded species of freshwater fish, six of them are native and twenty‐eight are introduced species. The success of cultivating native species lies mainly in the process of selecting species with potential and certain characteristics. Mariculture is relatively new in Mexico; it has been intensibly developed, mostly in the north‐west of the country. It has a great potential due to the high commercial value of its species, excellent quality and demand in the market. Ornamental aquaculture is the most developed in Mexico; the main producer is the state of Morelos, with total technological expertise in production of introduced and native species. It should be noted that this success has been achieved, in some cases, with the support of projects from government institutions, universities, research centres, associations and private companies. Pointing out that the common factor for a successful aquaculture practice is an ecosystemic and sustainable approach, continuously improving practices and fish farming management, while complying with regulatory standards.

The ecosystem approach to aquaculture 10 years on – a critical review and consideration of its future role in blue growth - Cecile Brugère; José Aguilar‐Manjarrez; Malcolm C. M. Beveridge; Doris Soto (Reviews in Aquaculture, 2019)
Over a decade ago, the ecosystem approach to aquaculture ( EAA ) emerged from discussions between the Food and Agriculture Organization ( FAO ) of the United Nations and international aquaculture experts on how to move aquaculture development towards greater sustainability. The purpose of this review is to critically examine the use and mainstreaming of the EAA in aquaculture development to date and consider its possible evolution in the next decade. We systematically searched citations of key EAA publications in the academic and related literature for the period 2007–2016 and analysed all relevant FAO publications and project documents. We assessed the lessons learnt from the past decade of EAA experiences, the opportunities the EAA has created and the links between the EAA and the new development agenda. Our review suggests that mainstreaming the EAA in planning processes has raised awareness of the usefulness of holistic and participatory approaches in aquaculture and helped to steer the sector towards greater sustainability. However, the approach has had varying degrees of resonance and uptake with different user groups. The emphasis on spatial planning that has developed as part of the EAA implementation efforts, and close links between the EAA and initiatives such as ‘blue growth’, constitute significant opportunities for the future of the approach, although its ability to tackle increasingly complex governance issues may be limited. Thus, it is now opportune to reconsider the EAA 's raison d’être , taking into account ongoing developments within and outside the aquaculture sector.

The adherence and colonization of microorganisms in fish gastrointestinal tract - Xuemei Li; Einar Ringø; Seyed Hossein Hoseinifar; Hélene L. Lauzon; Harry Birkbeck; Deguo Yang (Reviews in Aquaculture, 2019)
Eggs, gills, skin and intestinal tracts of fish harbour bacterial communities that are thought to impact fish health through their interaction with the tissues. In particular, the gastrointestinal ( GI ) tract possesses numerous microbes and is considered an infection route. During the infections caused by pathogenic bacteria, mucosal adhesion is a critical early phase and plays an important role in fish development. This review focused on knowledge regarding the adherence and colonization of microorganisms in fish GI tract mucus, including various methods such as in vivo , in vitro , and ex vivo , host specificity, lactic acid bacteria nonfish origin using the adherence of pathogenic bacteria, gnotobiotic approaches and molecular methods. However, probiotics might not be possible to truly colonize the digestive tract of fish. The term ‘ temporal colonization ’ might be a better phrase to use when discussing probiotic persistence and presence within the mucosal layer. Recent and promising results in this field were presented based on new perspectives and future research directions of the adherence and colonization of microorganisms in fish GI tracts.

Tilapia lake virus: a threat to the global tilapia industry? - Mona Dverdal Jansen; Ha Thanh Dong; Chadag Vishnumurthy Mohan (Reviews in Aquaculture, 2019)
Tilapia lake virus (TiLV) is a recently described virus affecting wild and farmed tilapines. At present, it has been reported on three continents (Asia, Africa and South America) and the number of countries where the agent has been detected is likely to increase rapidly as a result of increased awareness, surveillance and availability of diagnostic methods. Any lack of openness regarding the TiLV status of a translocating live tilapia population destined for aquaculture may inadvertently contribute to the spread of the agent. Currently, there is no cure for viral diseases in aquaculture and while vaccines and selective breeding have proved successful in reducing the severity of some viral diseases, there are currently severe knowledge gaps relating to TiLV and no effective, affordable vaccines are yet available. This paper summarizes the published scientific information on TiLV and highlights important issues relating to its diagnosis, mitigation and control measures. While there have been no scientific studies on the socio‐economic impact of TiLV, it may pose a significant threat particularly to small‐scale fish farmers’ livelihoods and wild tilapine populations if left uncontrolled. To aid disease investigations, the authors propose case definitions for suspected and confirmed cases of TiLV infections.

Multifunctionality of pond fish farms in the opinion of the farm managers: the case of Hungary - József Popp; Emese Békefi; Szabolcs Duleba; Judit Oláh (Reviews in Aquaculture, 2019)
Freshwater fish ponds, besides producing fish, function as valuable aquatic habitats, contribute to the maintenance and enrichment of the quality of the ecosystem, play an important role in water and landscape management, provide services for various recreational activities and contribute to the preservation of the cultural heritage. The multifunctional character of pond fish farming has been recognized for long time; however, recently it has also been realized that the deliberate multidirectional use of fish ponds (production, angling, recreation, education, etc.) offers additional economic benefits. Experience with the operation of multifunctional fish farms in Hungary has clearly shown that the diversification of activities is a promising alternative during the development of sustainable pond fish farming. However, further efforts are required to investigate the specificities and applicability of the various factors and also the optimal ratio between them to utilize the opportunities offered by multifunctional use of freshwater fish ponds. Research on multifunctional pond fish farming has mainly been limited to descriptions of the various functions of fish ponds, for example environmental services. However, the attitude of farm managers towards the possible multifunctional use of their farming system has never been investigated. In this study, the importance of the various existing or potential functions of a pond fish farm and their role in the future development of multifunctional pond fish farms have been investigated through the analysis of the appraisal of experienced farm managers by analytic hierarchy process. The results of the research provide empirical evidence that can be used for the elaboration of policies, development strategies, R&D and the legal frameworks needed for the sustainable development of multifunctional pond fish farming.

Application of herbal anaesthetics in aquaculture - Seyyed Morteza Hoseini; Ali Taheri Mirghaed; Morteza Yousefi (Reviews in Aquaculture, 2019)
Anaesthesia is a widely used tool in fish handling, sampling and surgery in aquaculture; thus, fish anaesthesiology has been studied for a long time. In this case, there are several common anaesthetics in aquaculture, namely tricaine methanesulfonate (a chemical agent) and clove oil (a natural agent). Recently, there was an increasing interest to use herbal materials (other than clove oil) in fish anaesthesia. In this review, current knowledge about the use of herbal anaesthetics has been summarized. To date, essential oils/extracts of different plants have been studied for fish anaesthesia; most of them belong to Lamiaceae , Verbenaceae , Lauraceae and Myrtaceae . In addition, menthol, linalool, myrcene, cineole, globulol, spathulenol, guaiol, caryophyllene oxide, terpinen‐4‐ol and dehydrofukinone are herbal compounds that their anaesthetic effects have been studied in fish. Compared with clove oil and eugenol as the most common herbal anaesthetic, all tested herbal materials are less efficacious to anaesthetize fish. Some plants’ essential oil/extract, namely Aloysia triphylla , Myrcia sylvatica , Lippia alba and Curcuma longa , have beneficial health effects including suppression of physiological and oxidative stress. There is a lack of data in mechanism of anaesthesia and health effects of the herbal anaesthetics, which should be followed in future studies. In addition, most of the current studies have focused on certain fish species such as silver catfish ( Rhamdia quelen ), tambaqui ( Colossoma macropomum ) and common carp ( Cyprinus carpio ), and in most of the studies, essential oils/extracts of South American plants have been used. Thus, there is a need to study other fish and plant species.

Early life stage bottlenecks of carnivorous molluscs under captivity: a challenge for their farming and contribution to seafood production - Iker Uriarte; Marcela Astorga; Juan Carlos Navarro; María Teresa Viana; Carlos Rosas; Carlos Molinet; Jorge Hernández; Jorge Navarro; Ignacio Moreno‐Villoslada; Rodolfo Amthauer; Gudrun Kausel; Jaime Figueroa; et al. (Reviews in Aquaculture, 2019)
This work brings together the view of different specialists in the areas of larviculture, physiology, ecology, nutrition and animal health, regarding how to deal with the aquaculture farming of species with complex life cycles in a multidisciplinary way, using as models the octopus and the muricid C. concholepas , with the aim of reducing the gap between the experimental and the industrial culture of species that are relevant for the diversification of aquaculture, particularly in Chile. Although these species are similar in their difficulty to reach the terminal planktonic phase prior to juvenile, they differ in the bottlenecks they have to overcome to reach it. Relevant aspects of study to achieve juvenile production from early life stages rearing, whether for repopulation or for ongrowing, are as follows: (i) Replacement or supplementation of live diets with inert diets to achieve significant survival values over the first stages of life. (ii) Physiological approaches to establish cultivation conditions evaluating the individual responses to several rearing conditions, specially the interaction between temperature, dissolved oxygen and acidity. Studies of urgent character due to the global warming scenario. (iii) Genomic studies associated with the effect of ontogenetic development, environment, health and nutrition on gene expression to understand, in an integrated way, the key processes for the development and growth of immature stages. (iv) Studies on the control of reproduction, the quality control of the ova, the genetic structure of reproductive populations and the characterization of diseases are also necessary to achieve efficient hatchery technologies.

Correction (New Zealand Journal of Marine and Freshwater Research, 2019)

Predicting seasonal ocean variability around New Zealand using a coupled ocean‐atmosphere model - Catherine O. de Burgh‐Day; Claire M. Spillman; Craig Stevens; Oscar Alves; Graham Rickard (New Zealand Journal of Marine and Freshwater Research, 2019)
We present a first assessment of the Sea Surface Temperature (SST) and 300m Heat Content (HC) ensemble mean skill of the Australian Community Climate and Earth‐System Simulator‐Seasonal v1.0 (ACCESS‐S1) around New Zealand on seasonal timescales, using a set of retrospective ensemble forecasts for 1990‐2012. This was verified against Reynolds AVHRR analysis and Bluelink ReANalysis 3.5 (BRAN3.5). For inshore areas with depth

Sediment grain size measurements are affected by site‐specific sediment characteristics and analysis methods: implications for environmental monitoring - Stephen Hunt; Hannah F. E. Jones (New Zealand Journal of Marine and Freshwater Research, 2019)
Sediment grain size, and specifically changes in the percent mud content (i.e. the fraction

Evaluating practical macrophyte control tools on small agricultural waterways in Canterbury, New Zealand - Kathryn E. Collins; Catherine M. Febria; Helen J. Warburton; Hayley S. Devlin; Kristy L. Hogsden; Brandon C. Goeller; Angus R. McIntosh; Jon S. Harding (New Zealand Journal of Marine and Freshwater Research, 2019)
Excessive macrophytes can cause significant problems in agricultural waterways requiring active management. Conventional control techniques can have a range of adverse effects. We investigated several control tools in two experiments: firstly, we tested eight treatments at a small‐scale (2 m × 2 m). We found intensive hand weeding, weed mat and herbicide spraying to be effective treatments, reducing macrophyte cover to

Impacts on CPUE from vessel fleet composition changes in an Australian lobster ( Jasus edwardsii ) fishery - John Feenstra; Richard McGarvey; Adrian Linnane; Malcolm Haddon; Janet Matthews; André E. Punt (New Zealand Journal of Marine and Freshwater Research, 2019)
The Australian Victorian Western Zone rock lobster fishery is assessed using standardised catch‐per‐unit‐effort (CPUE). Nominal CPUE declined over 1978–2009, but this underrepresents the estimated decline in abundance, and since 2009 standardised CPUE rose notably less than nominal CPUE. This study identified vessel as a key factor that explains the discrepancy between nominal and standardised CPUE. The composition of the fleet changed since 2009, under the pressure of constraining total allowable catch quotas, with vessels exiting the fishery having substantially lower estimated catchability, which increased the average catchability of the remaining fleet. New diagnostic indices were constructed to quantify discrepancies between trends in nominal and standardised CPUE that assisted in identifying periods during which both catchability and fleet composition changed.

The influence of environmental cues on the activity of silver eels ( Anguilla dieffenbachii ) in Lake Manapouri, New Zealand - Rose E. Stuart; Gerard P. Closs; P. Mark Lokman; Don Jellyman (New Zealand Journal of Marine and Freshwater Research, 2019)
Lake Manapouri in the South Island of New Zealand has a significant hydroelectric generation facility, which potentially has a negative impact on the successful emigration of longfin eels ( Anguilla dieffenbachii ) from the upper Waiau catchment. Consequently, a trap‐and‐transfer programme has been implemented to allow silver (migratory) eels access to the sea. The present study analysed data on the timing of captures and numbers of silver eels over four seasons, including the influence of possible migration cues. Silver eels were captured over an extended season of seven months (November–May), with peak numbers during December and January. Flow at the lake outflow was found to have a weak relationship with the number of eels caught, as did lake level, but moon phase and rainfall had no significant effect. These results highlight the variability in silver longfin eel behaviour both in terms of timing and response to potential environmental cues.

Distributions of settlers suggest greater dispersal and mixing of Ostrea chilensis larvae in Foveaux Strait, New Zealand - Keith P. Michael (New Zealand Journal of Marine and Freshwater Research, 2019)
The Foveaux Strait oyster ( Ostrea chilensis ) fishery in southern New Zealand comprises many localised populations (oyster beds) that have survived disease mortality and 150 years of fishing. The reproductive biology of O. chilensis underlies the assumption that these populations are self‐recruiting. A three‐year study using passive, artificial collectors deployed in a gradient design around an isolated natal population investigated the hypothesis of self‐recruitment. Spat settlement patterns measured the distributions of competent larvae as indicators of dispersal. This research also investigated the relationship between settler and brooder densities. Settler densities were not predicted by direction along or across the current, distance from the focal population, or by brooder densities. Settlement was widespread, and settlement patterns imply greater dispersal and larval mixing than previously reported. The swift currents and variable pelagic larval duration may enhance mixing and connectivity between populations. Demographically open recruitment should provide some resilience to disease mortality and fishing.

A checklist of the benthic and epiphytic marine dinoflagellates of New Zealand, including Rangitāhua/Kermadec Islands - Lesley Rhodes; Kirsty F. Smith (New Zealand Journal of Marine and Freshwater Research, 2019)
New Zealand benthic and epiphytic dinoflagellate records increased in recent years as harmful algal bloom research increased. This was largely due to risk assessments of micro‐algal biotoxins for the seafood industry and concerns regarding ciguatera fish poisoning in humans from toxic finfish. High‐throughput sequencing enabled the detection of dinoflagellate species that were previously overlooked by microscopy, particularly where diatoms or sediments obscured visual identification. This checklist includes new species records for New Zealand and species usually considered planktonic, but which have benthic life stages. Thirty‐one dinoflagellate genera were recorded from isolations and descriptions of living cells: Alexandrium, Amphidinium, Archaeperidinium, Azadinium, Biecheleria, Blastodinium, Bysmatrum, Coolia, Crypthecodinium, Cryptoperidiniopsis, Durinskia, Ensiculifera, Fukuyoa, Gambierdiscus, Gymnodinium, Gyrodinium, Heterocapsa, Karenia, Kryptoperidinium, Ostreopsis, Pelagodinium, Pentapharsodinium, Pfiesteria, Polarella, Prorocentrum, Protodinium, Protoperidinium, Pseudopfiesteria, Scrippsiella, Togula and Vulcanodinium . A further nine genera were detected by high‐throughput sequencing: Cachonina, Dinophysis, Fragilidium, Gonyaulax, Karlodinium, Lepidodinium, Protodinium, Symbiodinium and Woloszynskia .

Communicating biophysical conditions across New Zealand's rivers using an interactive webtool - Amy L. Whitehead; Doug J. Booker (New Zealand Journal of Marine and Freshwater Research, 2019)
Scientific research is often targeted towards predicting broad‐scale patterns in biophysical variables, with spatial data traditionally communicated using static figures and written descriptions in scientific journals and reports. However, inaccessibility and lack of flexibility mean that these communication methods have often hindered research uptake by resource managers and decision‐makers. We used R shiny to develop an interactive webtool that maps estimates of 109 biophysical variables, including hydrology, ecology and water quality metrics across the New Zealand digital river network. NZ River Maps is freely available online and can be used to visualise regional patterns, identify site‐specific characteristics and overlay regional planning layers. Interactive webtools improve on traditional communication methods by allowing inspection of predictions for selected sites and plotting of spatial patterns. The ability to quickly visualise and quantify relevant spatial data has enabled better communication of research outputs to provide robust and transparent inputs into environmental management.

First record of male freshwater eels ( Anguilla dieffenbachii ) caught at sea - Don J. Jellyman; Andrew I. Stewart (New Zealand Journal of Marine and Freshwater Research, 2019)
Two silver (migratory) male freshwater eels, Anguilla dieffenbachii , were caught in a commercial trawl net in the South Taranaki Bight in April 2014. The capture date and the relatively small eye size indicated that both eels had probably only recently entered the sea. This is the first record of male A. dieffenbachii caught at sea, en route to the presumed spawning area in the South Fiji Basin.

Salmon farming in Chile: key ecological and socio‐economic issues and challenges for the sustainable development of the sector - Doris Soto; Devin M. Bartley; Renato A. Quiñones (Reviews in Aquaculture, 2019)

Addressing viral and bacterial threats to salmon farming in Chile: historical contexts and perspectives for management and control - Jaime Figueroa; Juan Cárcamo; Alejandro Yañez; Victor Olavarria; Pamela Ruiz; René Manríquez; Claudio Muñoz; Alex Romero; Ruben Avendaño‐Herrera (Reviews in Aquaculture, 2019)
The rapid growth of the salmon farming industry in Chile has led to the appearance of various viral, bacterial, parasitic, and fungal pathogens affecting farmed fish. The Chilean salmon industry has suffered several health crises associated with high fish mortalities, such as caused by the infectious salmon anaemia virus (2007) and harmful algal blooms (2016). In addition to these events, marine farms are continuously affected by outbreaks of harmful pathogens, including the bacteria Piscirickettsia salmonis and, most recently, a reappearance of Renibacterium salmoninarum , and the infectious pancreatic necrosis virus. These outbreaks have led to stricter regulations, but the salmon farming industry continues to struggle despite reforms. In addition to the aforementioned pathogens, which are a continuous threat, other apparently under control pathogens have also reappeared in recent years. In this review, we analyse the current state of knowledge on four of the main pathogens affecting salmon farming in Chile. The infectious pancreatic necrosis virus is relevant as it affects freshwater‐stage fish, with survivors then acting as carriers. The infectious salmon anaemia virus currently appears to be under control; however, P. salmonis and R. salmoninarum continue to be the cause for high mortalities in the Chilean aquaculture industry.

Environmental issues in Chilean salmon farming: a review - Renato A. Quiñones; Marcelo Fuentes; Rodrigo M. Montes; Doris Soto; Jorge León‐Muñoz (Reviews in Aquaculture, 2019)
The growth of Chilean salmon production has not been free of important sanitary and environmental shortcomings. To ensure sustainability, it is necessary to understand the environmental impacts of salmon production on the Patagonian ecosystems. Currently, there is limited regulation or monitoring of impacts in the freshwater phase compared to the marine fattening stage, and there is some evidence of local eutrophication impact and diversity changes downstream the farms. Eutrophication of Patagonian channels and fjords from marine farms has been recognized as crucial environmental risk, although most scientific evidence comes from local effects below and around farms. So far, there are no regulations based on carrying capacity estimates to limit maximum fish biomass per area or water body. There is controversy regarding the potential role of nutrients derived from farming in triggering harmful algal blooms, yet current environmental monitoring and available information does not allow establishing or rejecting a cause–effect relationship. Pesticides used to control sea lice infestation have been shown to be deleterious to some non‐target species. There is evidence that the use of high quantities of antibiotics has allowed the development of antibiotic‐resistant bacteria in sediments and there is concern that salmon aquaculture has the potential to increase the proportion of antimicrobial‐resistant bacteria to antibiotics that are used in human medicine. There is an urgent need for more comprehensive ecosystem (beyond farm) studies on the impacts of antibiotics. Escapes of salmon (exotic species) from farms are a relevant environmental risk, although the most farmed species, Salmo salar , has shown little success in establishing wild populations. The review identifies critical knowledge gaps whose fulfilment is essential to advance towards an ecosystem approach to aquaculture and to protect Patagonian ecosystems.

Salmon farming vulnerability to climate change in southern Chile: understanding the biophysical, socioeconomic and governance links - Doris Soto; Jorge León‐Muñoz; Jorge Dresdner; Carol Luengo; Fabián J. Tapia; René Garreaud (Reviews in Aquaculture, 2019)
Here, we describe an assessment of climate‐change vulnerability for the salmon farming sector in southern Chile using a model that combines semi‐quantitative measures of Exposure (risks), Sensitivity (economic and social dependence) and Adaptation Capacity (measures that prevent and mitigate impacts). The evaluation was carried out in eight pilot communes representative of salmon production (marine grow‐out). Exposure was estimated with a semi‐quantitative risk assessment tool based on oceanographic, meteorological and hydrological information, mortality‐by‐cause databases, and through extended consultation with experts and relevant stakeholders. Threats included relevant changes in water temperature and salinity, declines in dissolved oxygen, occurrence of HAB s, and diseases that could be associated with climate change. Based on our analysis of the data, we divided the farming regions into four sub‐regions with distinctive oceanographic properties and superimposed the sea surface warming trend and a spatial pattern of mortality by respective cause. Reduction of precipitation and the increase of air and sea surface temperature are the most relevant foreseen climate change drivers, especially for regions X and XI . The resulting vulnerability matrix indicated that communes with higher production concentrations were more exposed, which in some cases coincided with higher sensitivity and lower adaptation capacity. Our models of four management scenarios allowed us to explore the changes in vulnerability associated with a southward movement of salmon production towards the Magallanes region. By identifying new protocols to increase adaptation and reduce vulnerability in a spatially explicit fashion, we provide policy recommendations aimed at increasing climate change adaptation and the long‐term sustainability of the sector.

The race between host and sea lice in the Chilean salmon farming: a genomic approach - Cristian Gallardo‐Escárate; Gabriel Arriagada; Crisleri Carrera; Ana Teresa Gonçalves; Gustavo Nuñez‐Acuña; Diego Valenzuela‐Miranda; Valentina Valenzuela‐Muñoz (Reviews in Aquaculture, 2019)
Sea lice are a group of ectoparasite copepods negatively affecting fish health in the salmon farming industry worldwide. Due to their biology, including several stages of development with different sensitivities to chemotherapeutants and their complex host–parasite interactions, the control of sea lice represents one of the major obstacles for sustainable aquaculture. Interdisciplinary approaches are required to avoid the environmental impacts of antiparasites commercially used during the fish production cycle and the increasing emergence of drug resistance in lice populations. Herein, control methods based on genomic analyses will allow for the development of novel tools such as vaccines, immune‐modulators, in‐feed masking compounds and non‐pharmacological therapies. This review highlights the genomic knowledge on the race between hosts and sea lice, with emphasis on Salmo salar and Oncorhynchus kisutch as host fish species and Caligus rogercresseyi as the main threat affecting the Chilean salmon industry.

Main issues and challenges for sustainable development of salmon farming in Chile: a socio‐economic perspective - Carlos Chávez; Jorge Dresdner; Yanina Figueroa; Miguel Quiroga (Reviews in Aquaculture, 2019)
We identify and discuss the main problems and challenges in sustainable development faced by the salmon farming industry in Chile from a socio‐economic perspective. This perspective is broad, in that it includes how the industry interacts with society and the environment, but also limited, in that it only assesses the impact on different social groups and economic agents. First, we present a brief description of the structure and socio‐economic relevance of salmon farming in the country. Second, we identify and discuss the primary current issues in the sustainable development of salmon farming in Chile. Third, we identify and discuss the challenges for developing sustainable salmon farming in Chile, including regulatory design and sectoral management, options for future expansion of the industry, responses and adjustments in the face of climate change and climatic variability, and the proper handling and growth of public‐private cooperation and goods governance.

Chinese Abstracts (Reviews in Aquaculture, 2019)

Advances in genetic improvement for salmon and trout aquaculture: the Chilean situation and prospects - Jean P. Lhorente; Marcelo Araneda; Roberto Neira; José M. Yáñez (Reviews in Aquaculture, 2019)
Genetic improvement is key to the development of a more efficient aquaculture industry. By 2010, there were 104 breeding programmes for aquaculture species in the world, most of them for fish species. Usually, the breeding goals include traits such as growth rate, disease resistance, maturation and carcass quality. Resistance to specific pathogens has been one of the main objectives of research and development in the genetic improvement programmes of salmonids in Chile and worldwide. In Chile, trait selection has been conducted through the application of selection indexes. New technologies like next generation sequencing and genotyping have helped disentangle the genetic basis and enhance genetic evaluation methods of economically important traits. This work aims to review the advances in genetic improvement for salmon and trout aquaculture with emphasis on the Chilean experience. We focus on the implementation of breeding programmes in the country, definition of breeding objectives, results on genetic parameters and response to selection and incorporation of genomics. Future challenges and opportunities regarding genotype‐by‐environment interactions, climate change and research and development, plus the demonstration of the economic benefit of breeding programmes are also addressed.

Issue Information (Reviews in Aquaculture, 2019)

Assessment of Holothuria arguinensis feeding rate, growth and absorption efficiency under aquaculture conditions - Jorge A. Domínguez‐Godino; Mercedes González‐Wangüemert (New Zealand Journal of Marine and Freshwater Research, 2019)
Holothuria arguinensis is a potential species for sea cucumber aquaculture in Europe. In a first experiment, feeding rate (FR), growth, absorption efficiency (AE) and survival of adults (135.01 ± 10.87 g eviscerated weight) were assessed under sediment tank conditions. In a second experiment, the feasibility to use sea bream ( Sparus aurata ) biodeposits as a food source was studied for adults (168.69 ± 14.59 g eviscerated weight). Individuals in the first experiment showed an increase of weight (specific growth rate (SGR) = 0.2% d −1 ), positive FRs and mean value of AE close to 80% with a mean organic matter content of 90.07 ± 11.5 mg/g in the offered sediment. Sea cucumbers fed with fish biodeposits showed a reduction of weight (SGR −1 ), low FRs and negative values of AE. The influence of low salinity and temperature during experiments should be considered to explain these results. Indeed, sea cucumbers can be affected by a decrease of these parameters during winter months resulting in a period of inactivity.

Emerging organic contaminants (EOCs) in freshwaters in Dunedin, New Zealand - Melody J. Bernot; Randall J. Bernot; Christoph D. Matthaei (New Zealand Journal of Marine and Freshwater Research, 2019)
Emerging organic contaminants (EOCs) in New Zealand freshwaters are not well documented for regulatory assessments. We collected water and sediment samples for measurement of 26 EOC compound concentrations at four waterways within the city of Dunedin (Otago province). Compounds measured ranged from stimulants and depressants to pain‐killers and insect repellants. Sampling was conducted before and after the student ‘Orientation Week’ at the University of Otago. Most compounds were below detection limits in all samples. However, caffeine, carbamazepine, cotinine and DEET were all measured at concentrations above detection limits. In general, concentrations of EOC compounds were ∼20% higher following the influx of students to the University though student effects varied by site and additional sampling is needed to better assess temporal variation in concentrations. These data indicate that some EOCs are present in New Zealand freshwater ecosystems.

Eutrophication In Lake Rotorua. 2. Using ROTAN and OVERSEER to model historic, present and future nitrogen loads - J. Christopher Rutherford; Christopher C. Palliser; Alastair MacCormick (New Zealand Journal of Marine and Freshwater Research, 2019)
OVERSEER is used in New Zealand to estimate nutrient losses from farmland, but does not quantify subsequent movement through the catchment, or attenuation. This paper uses the ROTAN model, based on the Scandinavian HBV‐N model, to route nitrogen losses from 1900–2015 to Lake Rotorua where groundwater age ranges from 14 to 170 years. ROTAN conceptualises three delivery pathways (quickflow, groundwater and streamflow) with different attenuation. When calibrated to measured stream and groundwater concentrations, several combinations of attenuation gave equally good fits largely because of sparse and uncertain input and calibration data. Nevertheless, lake N loads were predicted for current land use (754 ± 39 t y −1 ) and with proposed N loss reductions (431 ± 26 t y −1 ). Probabilities were also calculated that the reductions are more (12%–18%) or less (82%–88%) than required to meet the target lake N load (405 t y −1 ). ROTAN shows promise for calculating nitrogen movement in catchments dominated by groundwater where there is limited data.

Assessment of chemical and physical treatments to selectively kill non‐indigenous freshwater zooplankton species - Louis A. Tremblay; Olivier Champeau; Patrick L. Cahill; Steve Pullan; Natasha Grainger; Ian C. Duggan (New Zealand Journal of Marine and Freshwater Research, 2019)
Non‐indigenous zooplankton species pose a biosecurity threat to New Zealand’s freshwater native taxa. Nine species are known to have established in New Zealand lakes to date. The spread of some zooplankton taxa is linked to the translocation of farmed fish, principally grass carp ( Ctenopharyngodon idella ), and recreational vessel movements. The aims of this study were to assess the effectiveness of a range of chemical and physical treatments for transport water and associated equipment to kill freshwater cladoceran, copepod, and rotifer zooplankton species, and their risk to non‐target fish. Sodium chloride was the most effective and applicable chemical treatment tested at length in the cladoceran and, combined with physical treatment via mechanical filtration of water or hot water immersion of equipment (to also manage the risk of diapausing eggs), represents an effective option for the control of non‐indigenous zooplankton, with limited impact on stenohaline fish.

Editorial - Candida Savage (New Zealand Journal of Marine and Freshwater Research, 2019)

Age and life histories of black and smooth oreos inferred using bomb radiocarbon dating and stable isotope analysis - Peter L. Horn; Peter J. McMillan; Helen L. Neil (New Zealand Journal of Marine and Freshwater Research, 2019)
Black oreo ( Allocyttus niger ) and smooth oreo ( Pseudocyttus maculatus ) are commercially exploited deepwater fishes in New Zealand. They are considered to be long‐lived with unvalidated maximum otolith growth zone counts of 153 years and 86 years, respectively. Bomb radiocarbon dating results supported the otolith age estimates for A. niger , but those for P. maculatus provided only partial support. Oxygen isotope (δ 18 O) results for A. niger otoliths suggested that juveniles were in near‐surface waters and adults in depths of 700–1300 m. In contrast, P. maculatus otoliths suggested a variable depth history (500 to at least 1500 m) throughout life. Carbon isotope (δ 13 C) results showed a steady enrichment from core values to c. 20 years for both species, owing to changes in diet and metabolic rate from the juvenile to the adult fish, associated with a depth increase. Von Bertalanffy growth parameters are provided for both species.

Recent (post‐1930) changes in the extent of subtidal seagrass ( Zostera muelleri ) beds of the eastern Bay of Islands, New Zealand - John D. Booth (New Zealand Journal of Marine and Freshwater Research, 2019)
The surface areas of 12 subtidal seagrass Zostera muelleri beds at the islands and adjacent mainland shores of the eastern Bay of Islands (35° 12′ S, 174° 10′ E), New Zealand were estimated from aerial images. It appears that little subtidal seagrass existed until after the early‐1950s, so significant beds here may be a relatively recent biome. Possible explanations for recent emergence of subtidal seagrass include that debilitating periods of turbid water and pulses of sedimentation associated with the land clearances of the late 1800s had worked through the marine ecosystem. An overall peak in seagrass‐cover in the 1960s to 1980s was followed by declines in several beds in the 1990s to 2000s, with recovery since. The temporal presence of seagrass was well‐correlated among the three mainland beds, and moderately well among the south‐facing beds on the islands, consistent with mechanisms driving seagrass establishment and persistence operating at reasonably broad scales.

Diet composition of New Zealand’s endemic rough skate, Zearaja nasuta - Jerusha Bennett; Haseeb S. Randhawa (New Zealand Journal of Marine and Freshwater Research, 2019)
Diet analysis can provide an insight into the structure and function of an ecosystem, and can be used in ecosystem‐based frameworks to inform management and conservation decisions. Diet composition of rough skate ( Zearaja nausta ) from the south east coast of New Zealand, was investigated for the first time. We examined 35 stomachs from three trawls between March and June 2017. Prey importance was assessed by a prey specific index of relative importance (PSIRI). This population of rough skates (n = 32) was found to be specialised feeders, primarily preying on one species, Nectocarcinus antarcticus . This study provides the first insight into rough skate trophic interactions in the surrounding marine community.

DNA barcode, taxonomic and ecological notes for the identification of the invasive amphipod Monocorophium acherusicum (Costa, 1851) - Mariano J. Albano; Carlos Rumbold; Ignacio L. Chiesa; Guadalupe Vazquez; Eduardo D. Spivak; Sandra M. Obenat (New Zealand Journal of Marine and Freshwater Research, 2019)
We report the occurrence of the invasive amphipod Monocorophium acherusicum in Mar del Plata port, Argentina, using morphological and molecular analysis and estimated mean abundance to detect monthly variations of this population. We compared M. acherusicum morphology with that of M. insidiosum and Crassicorophium bonelli , the two most similar locally occurring species, to establish the diagnostic characteristics for the correct identification of them; moreover, we provide some taxonomic notes about others corophiids regionally distributed. M. acherusicum were collected in a subtidal biofouling community and its mean abundance was maximum in summer. In the molecular analysis, the maximum‐likelihood tree showed that specimens from Mar del Plata were clustered with M. acherusicum specimens from GenBank and Boldsystems. We support and confirm the species identity in Mar del Plata port using DNA barcoding and with taxonomic methods.

Physical and biological drivers of sediment oxygenation and denitrification in a New Zealand intermittently closed and open lake lagoon - Josie A. Crawshaw; Marc Schallenberg; Candida Savage (New Zealand Journal of Marine and Freshwater Research, 2019)
Intermittently closed and open lakes and lagoons (ICOLLs) are shallow estuarine ecosystems, many of which show eutrophication symptoms. The physical and biological drivers of sediment oxygenation and denitrification were examined in a New Zealand ICOLL using in situ enclosures for one year. Denitrification was seasonally and spatially variable, and higher denitrification rates were driven by organic matter availability, temperature and nitrate flux. The bulldozing invertebrates generally deepened oxygen penetration in 18% of oxygen profiles, consistent with their effect in multiple regressions. Chironomid larvae (Chironomidae) dominated the benthic community, and their tubular burrows modified oxygen penetration into the sediment in 18% of profiles, potentially affecting denitrification in the ICOLL through bioirrigation. Our study shows that macroinvertebrates support increased sediment oxygenation; therefore the use of artificial opening regimes in many ICOLLs may have negative effects on macroinvertebrate community composition and may consequently inhibit denitrification.

Issue Information (Reviews in Aquaculture, 2019)

Chinese Abstracts (Reviews in Aquaculture, 2019)

From an open‐access fishery to a regulated aquaculture business: the case of the most important Latin American bay scallop ( Argopecten purpuratus ) - Lotta C. Kluger; Marc H. Taylor; Matthias Wolff; Wolfgang Stotz; Jaime Mendo (Reviews in Aquaculture, 2019)
The South Pacific bay scallop Argopecten purpuratus represents a high‐value species harvested along the Peruvian and Chilean coastline for more than 60 years. Following the strong El Niño event of 1983/84, both countries experienced a boom in scallop fisheries, but catches dropped as soon as environmental conditions normalized. Aquaculture production began in Chile, which dominated the Latin American scallop market in the 1990s. Peruvian production remained small until the early 2000s, but has increased dramatically ever since, with a single location in northern Peru, Sechura Bay, contributing most (50%) to the Latin American scallop production. We review the historical trends of this species’ production and analyse the ecological and socio‐economic factors that have favoured Sechura Bay's progress, and largely displaced Chilean production through dominance of the market. Advantageous environmental conditions in Sechura Bay (e.g. low water depths, higher temperatures, high natural seed supply) result in improved scallop growth and production, and the socio‐economic factors, causing lower operational costs than those of the Chilean production favoured this development. The bottom‐up initiation of aquaculture operations by small‐scale producers likely created a personal incentive for the long‐term sustainable use, which differs from the more industrialized aquaculture activities in Chile.

A novel two‐stage seaweed integrated multi‐trophic aquaculture - Doron Yehoshua Ashkenazi; Alvaro Israel; Avigdor Abelson (Reviews in Aquaculture, 2019)
Marine aquaculture is undeniably a key future direction for the production of food. However, traditional aquaculture involves some significant drawbacks, the major one of which is the surplus discharge of organic matter and dissolved nutrients. To mitigate the environmental impact, integrated multi‐trophic aquaculture ( IMTA ) systems, which advocate the integration of fed fish with inorganic and organic extractive species, may offer a sustainable solution. This study focuses on an innovative experimental setting, integrating three marine macroalgae species ( Ulva rigida , Gracilaria conferta , Hypnea musciformis ) serially connected via two‐stage seaweed culture tanks to a finfish culture (the gilthead sea bream; Sparus aurata ). The aim was to compare and assess the biofiltration and growth performances of the seaweeds, while altering their order in the two‐stage system. The results indicated U. rigida as the fastest growing species. Ulva rigida also displayed the highest total ammonia nitrogen ( TAN ) uptake rates and removal efficiency. The design allowed the production of high tissue protein and carbohydrate levels for potential biorefinery uses. Ulva rigida protein content averaged 23%, while that of H. musciformis and G. conferta averaged 25% and 18%, respectively. Hypnea musciformis and G. conferta grown under low nutrient conditions presented a significantly higher total carbohydrate content of nearly 50%, compared to 34% exhibited by U. rigida . In summary, the seaweed pairing in a two‐stage system did not inhibit the performance of each individual species and improved overall production. Consequently, it offers significant advantages for future IMTA systems.

The use of feed and water additives for live fish transport - Myriam Vanderzwalmen; Lewis Eaton; Carrie Mullen; Fiona Henriquez; Peter Carey; Donna Snellgrove; Katherine A. Sloman (Reviews in Aquaculture, 2019)
The transport of live fish for aquaculture, either for food or as companion animals, presents a major issue for animal welfare. The stressors associated with live transportation are well documented with a focus on maintaining water quality during transport to reduce stress. Far less considered is our ability to enhance health and welfare during transport through the use of dietary and water additives prior to and during transport. With increasing interest in the use of plant essential oils as feed additives in food fish aquaculture and the increased availability of products claiming to alleviate stress in ornamental species, there is a need for scientific investigation into these potential welfare‐promoting methods. Here, we summarise current knowledge on the use of food additives, water conditioners, antibiotics, antimicrobials and probiotics to promote fish health during transport. This review aims to highlight the gaps in our knowledge surrounding promising ways of promoting fish health during transport and to stimulate new research in this area.

The future of caviar production on the light of social changes: a new dawn for caviar? - Benedetto Sicuro (Reviews in Aquaculture, 2019)
Caviar consumption is increasing, and main projections indicate that the presumable maximum production will be of 3000 t year −1 . From the productive point of view, the principal difference from the past caviar production is the definitive shift from wild to farmed caviar. Due to the recent advances in sturgeon aquaculture and the expansion of luxury consumers, there remains vast potential to reshape caviar consumption. Luxury market is extremely lucrative, it accounted for €217–€253 billion in 2016 and this is about 1.5 times of world aquaculture production. However, these perspectives are not only positive as this market segment is also affected by the diffusion of imitation (i.e. caviar substitutes, in this case). The proliferation of caviar substitutes can be interpreted as a kind of commercial Müllerian mimicry, while the adoption of new marketing strategy defined ‘Masstige’, which describes a downward luxury extensions directed towards middle‐class consumers and introduces new perspectives to this sector in its totality. What suggestions can be made by observing luxury consumers attitudes? This review takes into consideration the relation between sturgeon farming and quality of caviar on the light of modern societal changes. The main challenge for sturgeon aquaculture will be to spread a positive image of farmed caviar, thus introducing the aspects of excellence related to extensive aquaculture in controlled conditions by the adoption of shared rules on caviar quality. The most interesting aspects emerged are related to potential social expansion of caviar consumption, particularly in the middle‐class consumers.

Biosensors: a potential tool for quality assurance and food safety pertaining to biogenic amines/volatile amines formation in aquaculture systems/products - Veluthevar Ramanathan Heerthana; Radhakrishnan Preetha (Reviews in Aquaculture, 2019)
The present review focuses on the role of volatile amines as a quality indicator which affects the safety and acceptance parameters of the aquaculture products. The nurturing aquaculture requires good aquaculture practice to safeguard aquaculture environment. Particularly, poor water quality of aquaculture systems, changes in storage temperature after harvest and unhygienic handling practices enhance the growth of harmful microbes and thereby magnify the accumulation of biogenic amines (histamines, prolamines cadaverine, putrescine, spermidine, spermine, tyramine and tryptamine) and total volatile basic nitrogen (dimethylamine, trimethylamine and ammonia) content in the aquaculture products. Various conventional and advanced tools used to monitor the aquatic environment/aquaculture products are discussed in this review. Moreover, this review focuses on the biosensors used for determination of biogenic amines/volatile amines for assuring safety and quality of aquaculture products and aquaculture systems.

Shells from aquaculture: a valuable biomaterial, not a nuisance waste product - James P. Morris; Thierry Backeljau; Gauthier Chapelle (Reviews in Aquaculture, 2019)
Mollusc aquaculture is advocated as a highly sustainable food source and may play an important role in future food security globally. With production increasing worldwide, it is timely to appraise all aspects of aquaculture when considering its expanding role as a food source. In this regard, one regularly overlooked aspect of mollusc aquaculture is waste generation: namely the production of calcareous shells. Shells from the aquaculture industry are widely regarded as a nuisance waste product, yet at the same time, calcium carbonate is mined in the form of limestone and viewed as a valuable commodity. In a time of increased awareness of the need for a circular economy, the aquaculture and seafood industry should consider shells as a valuable biomaterial that can be reused for both environmental and economic benefit. This review discusses the current waste shell issue and identifies large‐scale shell applications that are already in place. Further, it highlights proposed applications that have the potential to be scaled up to address the problem of waste shell accumulations and reduce our reliance on environmentally damaging incineration and landfill disposal. Of the plethora of shell valorisation techniques proposed in the scientific literature, this review will focus only on those that can incorporate large‐scale shell utilisation, and do not require high‐energy processing, and are thus; simple, sustainable and potentially economically viable. Further, this review questions whether, in many cases, shells can provide more inherent value being returned to the marine environment rather than being used in land‐based applications.

Opportunities for strengthening aquaculture industry through multicriteria decision‐making - Francisco Vergara‐Solana; Marcelo E. Araneda; German Ponce‐Díaz (Reviews in Aquaculture, 2019)
In operations research, there are methodological tools included in decision theory that can help decision‐makers understand and systematize the decision‐making process. Decisions can be classified either as mono‐criterial, when only one criterion or goal is considered to evaluate its performance or multicriterial, which takes into account the interaction between two or more goals or criteria that can be in conflict. Natural resource management and finance are some important examples where the implementation of this type of tools has benefited the decision‐making process because they allow a number of criteria or objectives to be weighted in a transparent manner to assist when one or more decision‐makers are involved. Despite this, its application was not common in aquaculture; however, in recent years, efforts have increased exponentially. This work seeks to identify opportunity areas for development of new aquaculture‐related research through the implementation of multicriterial decision‐making methods (MCDM). To achieve this, a comprehensive bibliometric analysis was performed to detect MCDM applications that have been implemented in aquaculture industry (24 documents that were grouped into eight applications). Later, this information was complemented through the analysis of selected applications in natural resources management, specifically in fisheries, animal husbandry and agriculture. We propose 23 research topics relevant to the aquaculture industry that can be addressed by the methodologies in MCDM.

Predictive functional profiles using metagenomic 16S rRNA data: a novel approach to understanding the microbial ecology of aquaculture systems - Ángel Martín Ortiz‐Estrada; Teresa Gollas‐Galván; Luis Rafael Martínez‐Córdova; Marcel Martínez‐Porchas (Reviews in Aquaculture, 2019)
Micro‐organisms are an essential component of natural marine ecosystems, but also play important roles in anthropogenically modified ecosystems, including aquaculture. Although metagenomics is currently used to explore microbial communities, its application has not been as extensive in aquaculture. Although some taxonomic profiles and phylogenetic studies have been deciphered using biomarker genes, the functional potential of microbial communities associated with aquaculture systems is still unknown in most cases. Predicting functional profiles through 16S rRNA gene‐based metagenomics analysis is perhaps the most promising tool to elucidate the metabolic capabilities of microbial communities because there is no need to perform shotgun sequencing to have an idea of these capabilities. Moreover, robust bioinformatics background is not required to assess this information, and so the same data (16S rRNA sequences) are used to estimate both taxonomic and functional profiles, therefore providing deeper insights into these kinds of communities. In this review, we suggest the need to major use of novel bioinformatics tools that construct functional profiles from metagenomic 16S rRNA data, as strategy to obtain a preliminary approach about metabolic capacities of microbes that coexist in aquaculture systems.

Oyster culture on the Amazon mangrove coast: asymmetries and advances in an emerging sector - Dioniso de Souza Sampaio; Claudia Helena Tagliaro; Horacio Schneider; Colin Robert Beasley (Reviews in Aquaculture, 2019)
Oyster culture activity along the eastern Amazon mangrove coast in Pará state, Brazil, was evaluated using socio‐economic data to support its management and future development. Between 2013 and 2014, surveys were carried out in the region's seven oyster culture associations through interviews with the president of each association as well as with 56 members (72% of the total). Further data up to 2016 were obtained from annual reports of the Serviço Brasileiro de Apoio às Micro e Pequenas Empresas in Pará and the Instituto Brasileiro de Geografia e Estatística . Two associations stand out from the rest due to their larger on‐growing areas and total production in 2013. However, smaller associations are more efficient with higher production per unit area. Currently, oyster culture in Pará provides an alternative source of income for 80 families, where total production has increased from 8.25 tons in 2013 to 41.8 tons in 2016. Although associations have grown in number since 2006, along with increased capacity and production due to government assistance, in comparison with other regions of Brazil, they need to be better organized internally, including regular monitoring of growth, production and environmental variables, development of depuration facilities and improved distribution and presentation of products. Diversification of seed supply among different locations is desirable. There should also be less dependence on public funding and more partnerships with private enterprise, as well as active coparticipation in the development of legislation and public policies regulating both oyster culture and protection of natural oyster beds.

Trends in aquaculture sciences: from now to use of nanotechnology for disease control - Angélica Irasema Sibaja Luis; Estefânia Vangelie Ramos Campos; Jhones Luiz de Oliveira; Leonardo Fernandes Fraceto (Reviews in Aquaculture, 2019)
Aquaculture is increasingly important in global food production. Consequently, the control of diseases in aquaculture is essential, due to the potential environmental impacts, notably in terms of the states of health of freshwater bodies and the oceans. In this study, we review the possible uses of different management systems, highlighting essential oils and novel nanotechnological strategies, for the control of diseases in aquaculture.

Physiological roles of tryptophan in teleosts: current knowledge and perspectives for future studies - Seyyed Morteza Hoseini; Amalia Pérez‐Jiménez; Benjamin Costas; Rita Azeredo; Manuel Gesto (Reviews in Aquaculture, 2019)
Tryptophan is an essential amino acid with a huge functional versatility, in addition to its participation in protein synthesis. Because of the complexity of its metabolism, and the functional relevance of several of its metabolites, it directly or indirectly participates in a wide array of physiological pathways. This amino acid is a precursor for the synthesis of the neurotransmitter/neuromodulator serotonin (5 HT ), the hormone melatonin and kynurenine and related compounds such as kynurenic acid, quinolinic acid or niacin. Because of this, it has a key role in the regulation of processes ranging from the neuroendocrine to the immune system in vertebrates. In aquaculture, extensive research has been performed to optimize the levels of tryptophan in the commercial diets for many fish species. Providing adequate levels of this amino acid is critically important for fish growth but also for fish welfare, as tryptophan has been shown to modulate fish behaviour, stress responses, and antioxidant and immune systems. Currently, available data suggest a wide variation in tryptophan requirements of different species ranging 0.3–1.3% of dietary protein level, but recent evidence also shows that fish tryptophan requirements can greatly vary depending on the rearing conditions of the fish. We also review here the participation of tryptophan and related metabolites in different physiological functions that are crucial for fish welfare. The review covers the involvement of tryptophan in 5 HT ‐ and melatonin‐mediated functions, along with its participation in the regulation of the immune system and its role as an antioxidant and antitoxic agent in fish.

Terrestrial fatty acids as tracers of finfish aquaculture waste in the marine environment - Camille A. White; Skye H. Woodcock; Raymond J. Bannister; Peter D. Nichols (Reviews in Aquaculture, 2019)
Waste from open‐cage aquaculture flows directly into the marine environment from uneaten feeds, faecal material and dissolved nutrients. Sustainable management outcomes are regularly based on the dispersal patterns of the waste, with biochemical tracing a key tool in understanding the footprint of aquaculture. We examined the use of fatty acid ( FA ) analysis to trace aquaculture waste for this purpose, with the aim of identifying specific biomarkers for environmental applications, as well as identifying challenges that are regularly encountered. Overall, the widespread use of terrestrial‐based oils in the production of marine aquaculture feeds has increased the use of FA biomarkers to trace aquaculture waste across benthic and pelagic systems, in vertebrates, invertebrates and environmental samples such as sediment and seston. A combination of linoleic acid ( LA ), oleic acid ( OA ) and α‐linolenic acid ( ALA ), which are dominant C 18 FA in terrestrial seed and animal oils, is the most commonly used biomarkers, along with overall shifts in FA profile related to diet. A challenge regularly encountered, particularly in lower trophic species, was the capacity of an organism to biomodify or selectively spare certain dietary FA , which can mask assimilation of aquaculture‐derived FA . In these species, controlled feeding studies are needed to properly understand FA metabolism and to ensure correct interpretation of FA data collected from wild samples. Overall, as FA biomarkers have the capacity to link aquaculture waste in the environment with potential effect, they are a valuable and increasingly applied tool for examining the overall influence of aquaculture in marine ecosystems.

A review of grouper (Family Serranidae: Subfamily Epinephelinae) aquaculture from a sustainability science perspective - Michael A. Rimmer; Branko Glamuzina (Reviews in Aquaculture, 2019)
Aquaculture of groupers is carried out in tropical and subtropical areas throughout the world, but most production is from Asia, with three countries responsible for an estimated 92% of global production: China (65% of total production), Taiwan Province of China (17%) and Indonesia (11%). We calculate that there are at least 47 grouper species plus 15 grouper hybrids that have been trialled or are currently aquacultured. While grouper aquaculture has undoubtedly provided positive social and economic benefits to coastal communities in Asia, practices associated with grouper aquaculture have also led to widespread concerns regarding its environmental impacts. This paper reviews environmental, economic and social impacts of grouper aquaculture within a sustainability science framework. An update, building on early technical reviews of grouper aquaculture, was used to identify the main environmental, economic and social impacts. The main environmental impacts identified were as follows: seedstock sources, particularly the use of wild‐caught postlarval or juvenile fish as seedstock; the use of ‘trash’ fish as the major feed source; and water quality and substrate impacts of sea cage aquaculture. Significant economic and social impacts arising from grouper aquaculture include employment and income generation, but the economic impacts of disease outbreaks are significant, reducing fish survival to harvest size to around 50–70%. Current approaches to ameliorate negative impacts include the following: development and implementation of better management practices ( BMP s) at national level, and the development of a global ecolabel certification scheme by the Aquaculture Stewardship Council. Both these approaches have significant constraints, particularly when applied to small‐scale farmers who produce the bulk of farmed grouper. We conclude that there is a need for improved higher level coordination between the major producer countries to address identified sustainability constraints to grouper aquaculture.

Recent developments in aquaculture of Palmaria palmata (Linnaeus) (Weber & Mohr 1805): cultivation and uses - Britta Grote (Reviews in Aquaculture, 2019)
This review summarizes the recent literature on the biology, cultivation techniques and uses of the red seaweed Palmaria palmata ((Linnaeus) Weber & Mohr 1805). The paper covers its distribution, appearance and life cycle, the state of the art cultivation techniques for spore release and seeding, and the culture of meristematic fragments of fronds harvested from natural populations. Furthermore, culture conditions for P. palmata sporelings and gametophytes and set‐ups of tank and open sea culture are presented. For tank culture, relatively high irradiance and frequent seawater exchange to supply carbon dioxide and nutrients are the most important parameters. In open sea culture, site selection and system design play an important role. Land‐based culture has the advantage that optimum culture conditions can be applied and quality‐controlled, whereas nearshore cultivation is less costly and labour intensive. In addition, the bioremediation potential and the use of P. palmata in integrated multitrophic aquaculture ( IMTA ) are discussed. More research is needed to investigate bioremediation potential of different P. palmata strains. Recent developments in uses of P. palmata as food supplement, source of bioactive compounds, animal feed and compound for biofuels are presented. Finally, the possibilities of cultivation of P. palmata enhance the prospects for the expansion of the cultivation of this seaweed. However, future research is needed regarding balance of culture conditions, costs and biomass in land‐based tank culture and in terms of site selection, system design, maintenance and harvest techniques in sea cultivation to establish a commercialization of the aquaculture of this species in Europe.