A summary is presented of the anthropogenic debris recorded up to 2020 in stomachs of marine fishes from New Zealand waters. This material (mainly plastics) was found in the stomachs of 28 species, with 24 of these species identified in two studies alone. Most of the New Zealand records were not identified in recently published global assessments of plastic ingestion by fish; the likely reasons for this are discussed. Consumpt...

Coastal squeeze of saltmarshes (CSS) has substantially eliminated valuable intertidal habitats and worsened local tidal hydrological environment by disintegrating tidal creek networks and losing tidal connectivity (TC). In this study, we explored the process response of creek network structure and TC to CSS dynamics, taking the southern Bohai Bay of China as a case study area. With the Landsat series data and ArcGIS spatial an...

The relationship between water temperature and gonadal maturation of a landlocked ecophenotype of marine pejerrey ( Odontesthes argentinensis ) in La Salada de Pedro Luro lake was analysed during three spawning seasons. Mainly vitellogenic females were found in August (winter), some ovulating in October (mid‐spring) and with atretic oocytes in December (end of spring). In accordance with this, gonadosomatic index (GSI) and est...

Stream bank erosion has been anecdotally identified as an important source of sediment in New Zealand catchments, however, there have been few attempts to quantify its contribution. Here we use a radionuclide‐based sediment tracing approach to determine the relative contribution of stream bank‐ and hillslope‐derived sediment within three catchments in the upper North Island of New Zealand. Both lithogenic (radium‐226 and radiu...

Muddy, faecally‐contaminated river flood plumes in coastal waters are a hazard to contact recreation and bivalve shellfish consumption but are difficult to study, being episodic and transient. We used a new underway flow‐through sampler in a small, fast boat, to map a flood plume within Wellington Harbour, while simultaneously sampling water in the Hutt River inflow. Faecal contamination (indexed by E.coli) correlated with flo...

Environmental indicators that reliably describe estuary trophic response to nutrient loading are required for the effective management of New Zealand estuaries. A common estuary eutrophication response is frequent, extensive and persistent opportunistic macroalgae blooms. This study explores the utility of the Opportunistic Macroalgal Blooming Tool (OMBT) in the New River Estuary (∼4600 ha), a shallow intertidal‐dominated syst...

This paper emerges from a Marsden project, Let the River Speak, focused on the Waimatā River in Gisborne, bringing insights from mātauranga and wānanga together with a wide range of disciplines to produce innovative and engaged understandings of ki uta ki tai‐the life of rivers from the mountains to the sea. In Te Ao Māori, waterways are relational knots/nodes/strands in a meshwork of whakapapa that arises from exchanges betwe...

Estuaries are the receiving environment for catchment‐derived contaminants, the fate of which depends on the interplay between the estuarine geomorphology and hydrodynamics. In large estuaries, biophysical processes are spatially and temporally‐diverse, which makes understanding and managing the impact of human activities challenging. Here we use two common modelling approaches to explore the advantages and limitations of biop...

Why have mangroves and their ecosystems been so hotly contested over the last quarter century in Aotearoa New Zealand's northern waters? Central to ‘mangrove mania’ are multiple, competing and often antagonistic perceptions of the perceived risks posed by mangrove presence, their removal and efforts to restore them. Not surprisingly this has led to a chaotic mangrove knowledge space, with significant gaps in knowledge required...

There is often confusion and sometimes controversy over whether a specific habitat or ecosystem is considered a wetland. In 2021, the New Zealand High Court issued a judgement that the wetland rules in the Resource Management (National Environmental Standards for Freshwater) Regulations 2020 (NES‐F) do apply to wetlands in the Coastal Marine Area (CMA), more particularly which ones apply to ‘natural wetlands’. From a scientifi...

Estuaries are hotspots of primary productivity and nutrient transformation that contribute to food webs and ecosystem functioning locally and in adjacent ecosystems. The depth‐dependence of nutrient transformation and primary productivity rates in the water column and the seafloor were investigated, and the lateral transport of solutes and materials across the estuary mouth were quantified. Using an estuary dominated by shallo...

Water quality in estuarine and coastal waters of Aotearoa New Zealand is of concern yet currently under‐monitored, reflecting challenges of sampling at regular intervals across large areas. Satellite products are currently underutilised (globally) by management agencies but could be part of a holistic approach. NIWA‐SCENZ (Seas, Coasts and Estuaries New Zealand) is a website providing access to MODIS‐Aqua products at moderate...

Estuaries are threatened with increasing sedimentation and nutrients, however research is limited on the interaction of these stressors on ecosystem functions. A field experiment adding nitrogen (N) fertiliser at high (600 g N m −2 ) and medium (150 g N m −2 ) concentrations and control plots was established in two sandy and two muddy sites (mud content 0–15%) to investigate context dependency of nitrogen enrichment on nutrien...

Many estuaries are squeezed between sea‐level rise, coastal hardening and adverse cumulative effects from unsustainable catchment activities. In Aotearoa New Zealand, there is little planning to provide future accommodation space for estuaries. A complex knot of policies and plans, and accompanying poor implementation also affect ecological sustainability. We examine these issues for Brooklands Lagoon/Te Riu o Te Aika Kawa, a...

Community participation is increasingly embedded into environmental policy with the aim of accelerating transformative change towards sustainable management. A common approach to engaging with communities is through key stakeholders, who are still often selected ad hoc based on their activities. We tested an analytical approach for identifying distinct groups of community preferences as part of a case study to develop a commun...

Mātauranga Māori (Māori knowledge) is grounded in place‐based, multi‐generational knowledge and the connection of that knowledge with the environments from which it is derived. It takes for granted that all elements of the natural world are related, and it is upon those relationships that survival depends. A Māori worldview advocates for the responsibility of each generation to pass onto their descendants at least as good a su...

The article analyses participatory processes in estuary restoration in Maketū on the East Coast of the North Island to examine how evolving relational dynamics amongst key stakeholders and Māori led to the achievement of a collective environmental imaginary. The case, marked by a history of conflict over the diversion of the Kaituna River and resulting estuary degradation, led to a focussed period of community engagement betwe...

Estuaries are complicated systems to manage effectively, requiring the monitoring of robust environmental indicators to assess health and detect changes. Routine estuarine monitoring programmes in New Zealand have only existed for 30 years at most, but estuaries have been significantly affected by anthropogenic pressures for at least 100 years. We reconstructed long term changes in indicators of estuarine health using historic...

Despite the Southern Hemisphere's high proportion of endemic diadromous fish, the trophic role of upstream migrating forage fish in freshwater ecosystems remains unquantified. We combined food web δ 13 C and δ 15 N analyses with fish biomass estimates to quantify estuarine resource contribution (from the ecologically significant Waituna lagoon) to the diet and growth of the apex predators, longfin eels ( Anguilla dieffenbachii...

Sea level rise (SLR) has been described as one of the greatest potential causes of ecosystem disruption, putting many coastal areas at risk of irreversible changes. However, the loss of intertidal areas from SLR and the associated ecological and social repercussions receive little attention. Within estuaries, extensive intertidal areas harbour a variety of habitats and communities and represent hotspots of ecosystem functions....

Throughout the evolution of fish nutrition science, the importance of dietary arachidonic acid (ARA, 20:4n‐6) has been somewhat overlooked, likely due to the polarizing research focus on docosahexaenoic (DHA, 22:6n‐3) and eicosapentaenoic (EPA, 20:5n‐3) acids. Nevertheless, especially during the past two decades, increasing attention has been paid to the requirements and functions of ARA in fish nutrition, and a number of rele...

The spiny lobsters Panulirus ornatus and Panulirus homarus are important developing tropical aquaculture species, with high demand and limited supply. The established industry in Vietnam relies on wild‐caught mixed seafood bycatch as feed, a practice linked to water quality degradation and potentially disease proliferation in lobster aquaculture, necessitating formulated feed development. The emerging Indonesian and Australian...