McGregor-Tiatia, V.L.; Langley, A.D. (2026). Assessment of hoki (Macruronus novaezelandiae) in 2025. New Zealand Fisheries Assessment Report 2026/04. 241 p.

Integrated stock assessments provide estimates of stock status based on available data and information. Stock status is the current biomass of the stock as a percentage of the biomass before the stock was fished. This report presents an integrated stock assessment for hoki, New Zealand’s largest finfish fishery. It includes information on movement and biology of hoki and data from commercial fisheries and research surveys.

The base model assumes there are two hoki stocks: an eastern stock that spawns in the Cook Strait and off the east coast of South Island; and a western stock that spawns off the west coast of South Island. To allow for uncertainty in this assumed stock structure, an alternative model with a single stock is also presented. Results from the assessment estimated current stock status to be at 55% of its unfished level for the eastern stock and 39% for the western stock. The combined stock status was estimated to be 45% (two-stock model) or 44% (single-stock model) of its unfished level. All assessments indicate the stock status for hoki is currently within the management target range of 35–50% of its unfished level.

• 100 years of weigh station records of individual fish from some sportfishing clubs.
• 50 years of charter boat average catch per day fished for marlin.
• 50 years of tag and release information from the Gamefish Tagging Programme.
• 47 years of the number of billfish, sharks, and tuna weighed by sport fishing clubs.
• 19 years of daily catch and effort data from the Billfish Logbook Programme.

Roberts, J.; Webber, D.N. (2025). Spatial risk assessment of threats to yellow-eyed penguin/hoiho (Megadyptes antipodes). New Zealand Aquatic Environment and Biodiversity Report No. 370. 162 p.

This research assessed the threats facing the northern population of yellow-eyed penguins/hoiho. The northern population includes the New Zealand South Island/Te Waipounamu and Stewart Island/Rakiura. Population models were developed for regional sub-populations from 1991 to 2023, to track changes in population size over time. The study found that hoiho numbers have declined across all areas, driven mainly by poor survival of juveniles and adults.

• Key threats include commercial set-net entanglements, which caused an estimated 17 deaths in 2022–23, mostly around Otago Peninsula, where risks have risen sharply since 2018–19.
• Malnutrition affects chicks and juveniles the most, particularly females, diseases have the greatest effect on chicks and juveniles, and predation primarily affects juveniles and adults.
• Warming sea temperatures across their range correlate with lower survival rates across all ages, suggesting climate change impacts on their main prey species.
• Otago Peninsula faces the highest overlap with human-related threats including direct interactions with humans and their dogs, recreational netting, oil spill risk, and other threats.

Projections su

Tait, L.W.; Pearson, R.; Whiteside, A; Thoral, F.; Mangan, S. (2025). Satellite derived national time series of giant kelp (Macrocystis pyrifera) abundance and key environmental drivers. New Zealand Aquatic Environment and Biodiversity Report No. 366. 50 p.

Giant kelp is one of the largest and fastest growing seaweeds in the world, it provides food and habitat for marine life, and engineers the physical environment around it. It is also a managed fishery in Aotearoa New Zealand. Because of its key role in supporting marine fisheries (particularly pāua, kina, kōura, and several key finfish) and the increasing interest in the commercial harvesting of seaweeds, we need a greater understanding of the current distribution of giant kelp.

Here we utilise satellite remote sensing to track the distribution of giant kelp across Aotearoa New Zealand over the last decade. Satellites provide a passive and free tool for monitoring the expanse of surface canopies. This is particularly relevant as kelp forest ecosystems are impacted by extreme events such as marine heatwaves and cyclones.

We show that satellite remote sensing of giant kelp can be used effectively to track the status and health of giant kelp which provides a powerful tool for identifying the drivers of change in kelp beds. By looking for relationships between key environmental parameters and kelp forest coverage, we found that national level declines in giant kelp beds are highly associated with per

Spyksma, A.J.P. (2025). Summarising and updating knowledge on the distribution of kina barrens in key regions of Aotearoa New Zealand. New Zealand Aquatic Environment and Biodiversity Report No. 365. 45 p.

Kelp forests are highly productive ecosystems but are increasingly threatened by overgrazing from sea urchins, creating persistent “urchin barrens.”

In New Zealand, kina is the main urchin barren forming sea urchin, with fishing pressure on predators like snapper and rock lobster considered a key driver of urchin barren formation, particularly in northeastern New Zealand.

Despite widespread reporting of urchin barren habitats there has been no previous efforts to collate urchin barren distribution information across the country.

This study collated 27 data sources to produce a nationwide overview of urchin barren distribution and extent.

Barrens occur throughout the country, with large areas in northeastern New Zealand, Marlborough Sounds, Tasman Bay, Fiordland, and Stewart Island.

Additional aerial imagery mapping revealed barrens along ~36% of northeastern NZ’s rocky coastline, mostly on shallow, nearshore reefs, though estimates are conservative.

The resulting datasets provide a national starting point for future work and will help to inform management, track kelp forest recovery, and sup

Neubauer, P.; Kim, K.; Hill-Moana, T.; Langley, A. (2025). Considering ecosystem aspects when setting management targets for New Zealand’s fisheries: Insights from simulations and application to snapper and gurnard in FMA 7. New Zealand Fisheries Assessment Report 2025/40. 62 p.

We studied the implications of managing fish stocks in New Zealand by considering the wider ecosystem, instead of only focusing on individual fish species. We examined snapper and gurnard fisheries in the Tasman Bay Golden Bay areas to see what happens when fishing targets are set higher than traditional levels. Using computer simulations, we tested different management approaches that would leave more fish in the ocean than current practices typically require.

We found that keeping fish populations at higher levels led to more and bigger fish. However, this approach also meant fishers could catch 20 to 45% fewer fish, potentially reducing economic returns. Whether higher fish population targets made economic sense depended strongly on fishing costs—expensive operations benefited because they needed less effort to catch quotas, whereas cheaper operations lost money due to smaller catches.

We showed that snapper and gurnard fisheries are closely connected, with over half of snapper catches happening when boats were declaring gurnard target fishing. Managing one species differently affects the other, showing that it is important to con

Roberts, J. (2025). Harbour use by Māui/Hector’s dolphin and commercial net fisheries. New Zealand Aquatic Environment and Biodiversity Report No. 363. 56 p.

This document provides a summary of existing information of the use of West Coast North Island (WCNI) harbours by Māui/Hector’s dolphins (Cephalorhynchus hectori) and by commercial net fisheries.

Based on this review, Māui/Hector’s dolphins were much more frequently encountered in the coastal domain of the WCNI. By comparison, sightings and acoustic detections in harbour areas were much more infrequent and almost entirely located inside fishing prohibition areas in harbour mouths.

Commercial net fishing effort was described using recent data collected using electronic monitoring, which includes the locations of all reported fishing events. The two main net fishing methods used in WCNI harbours are set-nets and ring-nets, which differ in terms of the gear used and the nature of fishing operations. The overlap of harbour-based set-net effort with the dolphins is likely to be very low. By comparison, the overlap with ring-net fishing with the dolphins is likely to be a little higher in some harbour mouths, although ring-net fishers must attend their gear throughout short deployments, so this method is considered less likely to capture Māui/Hector’s dolphins. 

However, several opportunistic sightings of Hector’s and Māui dolphins were

Finucci, B.; Bennion, M.; Chin, C.; Duffy, C.A.J.; Morrison, M.; Struthers, C. (2025). Identification and mapping of habitats of significance for sharks. New Zealand Aquatic Environment and Biodiversity Report No. 361. 248 p.

The aim of this project was to review existing literature and analyse data to identify areas that may be further identified as a habitat of particular significance (HoPS) for chondrichthyans (sharks, rays, and chimaeras). This project proposed 30 HoPS for 20 species of interest: six of the 20 species had at least one potential HoPS for spawning purposes identified and 10 species had at least one suspected potential HoPS identified. There were four species (blue shark, mako, porbeagle, basking shark) where potential HoPS could not be identified. No proposed HoPS is completely closed to fishing, and 22 proposed HoPS are completely open to fishing. All species evaluated here need further information to reduce knowledge gaps. Focal species and areas for future research, and alternative opportunities to collect data are discussed.