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This site contains documents relating to Fisheries New Zealand and predecessors’ funded research from 1988 to the current date. To find the documents applicable to you, please expand the filter and select the relevant search parameters. If you identify errors or inconsistencies in the categorisation of specific documents please advise us by emailing Science Officer.
 
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35607/05/2025
Title: AEBR 356 Effect of changing sea temperatures on pāua (Haliotis iris) physiological condition at two sites in the Chatham Islands, New Zealand
AEBR-356-2025-Effect-of-changing-sea-temperatures-on-paua-physiological-condition-at-two-sites-in-the-Chatham-Islands-New-Zealand.pdf (5.7 MB)
 The Chatham Islands to the East of the South Island of New Zealand are in an area that has been identified as experiencing frequent marine heatwaves. We investigated the effect of changing sea surface temperatures on adult and sub-adult pāua (Haliotis iris) collected from Ascots Beach and Owenga Harbour in the Chatham Islands, between 2020 and 2022. Pāua at the two sites reacted differently to temperature changes based on microbial diversity and metabolic profile findings. Site specific differences were detected in histological assessments with pāua from Ascots Beach showing reproductive abnormalities and pāua from Owenga Harbour showing an increased presence of kidney stones. 
AUTHOR: Alfaro, A.C.; Venter, L.; Guo, J.; Copedo, J.S.; Nguyen, T.V.; Sharma, S.S.; Azizan, A.; Ericson, J.A.; Ragg, N.L.C.; Cooper, J.; McCowan, T.; Cameron, N.; Mundy, C;
 06/05/2025
Title: FAR 2025/22 Catch-at-age of snapper in SNA 7 in the 2022–23 and 2023–24 fishing years
FAR-2025-22-Catch-at-age-of-snapper-in-SNA-7-in-the-2022-23-and-2023-24-fishing-years.pdf (2.0 MB)
Snapper is New Zealand’s most important commercial and recreational inshore finfish species.
 
This report describes a research study conducted in 2022–23 and 2023–24 to find out the size and age of snapper in the commercial bottom trawl catch in SNA 7, which covers Tasman and Golden Bays (TBGB) and the west coast of the South Island (WCSI). For TBGB this project contributes to a timeseries extending back to 1992–93. This is the first study to investigate snapper size and age on the WCSI.
 
While some difficulties were experienced obtaining samples in 2022–23, access to electronic reporting data from fishing vessels greatly improved sampling in 2023–24. In 2022–23, a total of 26 landings were sampled and 1496 otolith pairs aged; whereas in 2023–24, 43 landings were sampled and 1796 otolith pairs were aged.
 
Aging of otoliths has revealed that the bottom trawl catches in both TBGB and WCSI are dominated by young snapper, mostly five and six years of age and with average sizes of between 38 and 43 cm. Previous strong year-classes (notably 13 and 16 year old fish) are still present in the fishery, but are now of lesser importance (i.e., their abundance has decreased over the years since they were first present in the fishery). Overall, the SNA 7 fishery now includes multiple strong year-classes, which is generally a sign of an improving fishery.
&n
ISBN: 978-1-991345-80-6;
ISSN: 1179-5352;
FAR: 2025/22;
AUTHOR: Parsons, D.M.; Bian, R.; Walsh, C.; Johnson, K.; Smith, M.; Hart, A.; Sutton, C.; Olmedo-Rojas, P.; Stead, J.; Olsen, L.; Madden, B.; Armiger, H.;
 06/05/2025
Title: AEBR 355 Spatial risk assessment for selected shark species in New Zealand – Part II: trawl bycatch
AEBR-355-2025-Spatial-risk-assessment-for-selected-shark-species-in-New-Zealand-Part-II-trawl-bycatch.pdf (14.1 MB)
This report describes application of a novel risk assessment approach to trawl bycatch (non-target) shark species. The assessment estimated the exploitation rate inflicted on each of twelve species by fishing in the New Zealand Exclusive Economic Zone. Although trawl catches predominated, all relevant fishing methods were included so that the total fisheries impact could be gauged. The exploitation rate is a measure of the proportion of the selected population biomass that is killed as a result of fishing, and includes those individuals that die even when returned to the ocean. The exploitation was compared to a theoretical productivity measure to estimate whether it was high enough to inflict long-term damage on the population. Elephantfish (Callorhinchus milii) and carpet shark (Cephaloscyllium isabellum) were identified as being at higher risk from fishing.
ISBN: 978-1-991345-68-4;
ISSN: 1179-6480;
AEBR: 355;
AUTHOR: Edwards, C.T.T.;
 06/05/2025
Title: AEBR 354 Spatial risk assessment for selected shark species in New Zealand – Part I: pelagic bycatch
AEBR-354-2025-Spatial-risk-assessment-for-selected-shark-species-Part-I-pelagic-bycatch.pdf (7.2 MB)
 This report describes application of a novel risk assessment approach to pelagic bycatch (non-target) shark species. The assessment estimated the exploitation rate inflicted on each of six species by fishing in the New Zealand Exclusive Economic Zone. All relevant fishing methods were included so that the total fisheries impact could be gauged. The exploitation rate is a measure of the proportion of the selected population numbers that are killed as a result of fishing, and includes those individuals that die even when returned to the ocean. The exploitation was compared to a theoretical productivity measure to estimate whether it was high enough to inflict long-term damage on the population. Thresher shark (Alopias vulpinus), porbeagle (Lamna nasus) and mako shark (Isurus oxyrinchus) were identified as being at higher risk from fishing and risk for the protected basking shark (Cetorhinus maximus) and white pointer shark (Carcharodon carcharias) was lower but still non-negligible.
ISBN: 978-1-991345-67-7;
ISSN: 1179-6480;
AEBR: 354;
AUTHOR: Edwards, C.T.T.; Pinkerton, M.H.; Dunn, M.;
2025/2106/05/2025
Title: FAR 2025/21 Results of the 2023–24 Pāua Catch Sampling project
FAR-2025-21-Results-of-the-2023-24-paua-Catch-Sampling-project.pdf (4.6 MB)
 This report summarises pāua shell length information collected by sampling the commercial catch from areas PAU 2, PAU 3A, PAU 3B, PAU 4, PAU 5A, PAU 5B, PAU 5D and PAU 7 during the 2023–24 fishing year.
 
Over the last few seasons the length frequency distributions from PAU 5A show that there has been a decrease in the overall length of pāua measured live on the SciElex boards. All other areas were typical of commercial pāua fisheries, and consistent with previous years.
AUTHOR: Cooper, J.P.; McCowan T.A;
2025/2009/04/2025
Title: FAR 2025/20 The 2024 stock assessment of red rock lobsters (Jasus edwardsii) in CRA 4
FAR-2025-20-The-2024-stock-assessment-of-red-rock-lobsters-in-CRA4.pdf (15.2 MB)

The red rock lobster (Jasus edwardsii) supports the most valuable inshore commercial fishery in New Zealand. This fishery has been managed with catch quotas in nine Quota Management Areas (QMAs), which are usually treated as independent populations or stocks.

This document describes a stock assessment of red rock lobster in CRA 4 up to the 2023–24 fishing year. This stock assessment suggests that CRA 4 has experienced periods of biomass peaks and troughs over the time series modelled and has been increasing towards a peak for the past decade. This pattern has likely been driven by variability in recruitment and catch rates. Projections suggest the stock may hit a peak in biomass over the next five years.

AUTHOR: Rudd, M.B.; Webber, D.N.; Starr, P.J.; Roberts, J.; Pons, M.;
 07/04/2025
Title: FAR 2025/18 Additional analyses for orange roughy (ORH 3B)
FAR-2025-18-Additional-analyses-for-orange-roughy-ORH3B.pdf (5.7 MB)
 
  • We investigated orange roughy stock assessments for Chatham Rise, part of ORH 3B.
  • Stock assessments for this region have encountered problems, with models much more optimistic about stock status than suggested by fisheries statistics and some research surveys.
  • We describe skipper information on orange roughy behaviour and target fishing, the biology of orange roughy with respect to their sensory abilities, and observations of orange roughy responding to objects in the water column and to fishing disturbance.
  • Investigations of fisheries catch per unit effort found evidence of disturbance, where recent fishing activity reduced catch rates. The disturbance effect was considered useful but was not a “game changer”.
  • Seasonal trends in sea temperature, primary productivity, weather, and sea state, could be simply described using a “month” variable.  Spatial and regime shift models improved the fits to data.
  • Observed changes in orange roughy age frequency distributions have been poorly fitted in recent stock assessment models, but were better fitted here by models assuming reproduction had dropped to a very low level once the fishery started. One hypothesis that might explain this result is that fishing disturbance reduced reproducti
FAR: 2025/18;
ISSN: 1179-5352;
ISBN: 978-1-991345-46-2;
AUTHOR: Dunn, M.R.; Doonan, I.J.; Anderson, O.F.;
35307/04/2025
Title: AEBR 353 Environmental Health Measures for Open Ocean Aquaculture – Physiological responses of epifauna to enrichment under laboratory and field studies
AEBR-353-2025-Environmental-Health-Measures-for-Open-Ocean-Aquaculture-Physiological-responses-of-epifauna-to-enrichment.pdf (9.1 MB)
 Offshore finfish farming is expanding in New Zealand, but we lack knowledge about how seabed habitats and their species will respond to organic enrichment (in the form of faeces and waste feed) from salmon farms. This report, part of the Environmental Health Measures for Open Ocean Aquaculture project, investigates these impacts through laboratory and field experiments on three species: horse mussels, brachiopods, and scallops. Lab trials tested responses to controlled levels of enrichment, while field trials monitored animals near an operational salmon farm in the Marlborough Sounds.
 
              Key Findings
•Fatty acid tests showed that all species absorbed salmon waste, which affected their nutritional health.
•Breathing rates increased with enrichment in horse mussels and brachiopods, suggesting they were using more energy to survive.
•Changes in gene activity were strong in the lab but weaker in the field, potentially showing early warning signs of stress.
•Some animals developed health issues, including parasites in horse mussels and scallops, and tissue changes possibly linked to changes in their diet or normal variations in living functions.
•Overall, the effects did not cause death, with N. lenticularis showing higher tolerance than the two bivalve species. 
AUTHOR: McMullin, R.; McGrath, E.; Bennett, H.; Copedo, J.; Ericson, J.; Delorme, N.; Miller, M.; Biessy. L.; Pearman, J.;
 07/04/2025
Title: FAR 2025/19 Operational management procedures for New Zealand rock lobster (Jasus edwardsii) in CRA 7 and CRA 8 for 2025–26
FAR-2025-19-Operational-management-procedures-for-New-Zealand-rock-lobster-in-CRA7-and-CRA8-for-2025-26.pdf (1.6 MB)

The red rock lobster supports the most valuable inshore commercial fishery in New Zealand. This fishery has been managed with catch quotas in nine Quota Management Areas (QMAs), which are usually treated as independent populations or stocks.

The catch quotas are calculated for some QMAs using management procedures (MPs). Given an input, such as catch per unit effort (CPUE), MPs return an output such as Total Allowable Commercial Catch (TACC).

 

This document describes the operation of the current MPs used to manage New Zealand red rock lobster (Jasus edwardsii) in CRA 7 and CRA 8 for the 2025–26 fishing year. The operation of the MPs for the upcoming 2025–26 fishing year indicated that there should be no change in TACC for CRA 8, but indicated an increase in TACC for CRA 7.

FAR: 2025/19;
ISSN: 1179-5352;
ISBN: 978-1-991345-48-6;
AUTHOR: Webber, D.N.; Roberts, J.; Pons, M.; Rudd, M.; Starr, P.J.;
 07/04/2025
Title: AEBR 352 Marine heatwaves and fisheries in Aotearoa New Zealand: review of potential effects on marine ecosystems and fishstocks
AEBR-352-2025-Marine-heatwaves-and-fisheries-in-New-Zealand-review-of-potential-effects-on-marine-ecosystems-and-fishstocks.pdf (3.2 MB)
This research reviewed current data and information about marine heatwaves in New Zealand and their potential effects on marine ecosystems and fisheries. A marine heatwave is a prolonged period of warmer-than-usual water. Such events are increasing in frequency and intensity globally. Aotearoa New Zealand (Aotearoa-NZ) has experienced several in the last decade, and marine heatwaves are predicted to become more frequent and intense, and to last for longer, in the future.

Scientific reports from overseas suggest that marine heatwaves could affect both individuals and populations, causing redistributions such as range expansions or contractions, and affect reproductive success and survival of early life stages. In Aotearoa-NZ, spatial redistributions have been observed but whether they were caused by environmental change is unknown or speculative. Fishes may also be impacted by marine heatwaves through ecosystem changes, in particular the distribution and abundance of prey, changes to biogenic habitat, and disease, as much as through direct physiological effects.
 
We reviewed published information on 32 species or species groups of importance to fisheries in Aotearoa-NZ. Documented evidence of the impact of marine heatwaves in New Zealand were only found for green lipped mussel, snapper, and king (chinook, quinnat) salmon. Some information was found for bluefin tuna, rock lobster, and snapper outside of Aotearoa-NZ. Further inte
AEBR: 352;
ISSN: 1179-6480;
ISBN: 978-1-991345-47-9;
AUTHOR: Cook, K.M.; Dunn, M.R.; Behrens, E.; Pinkerton, M.H.; Law, C.; Cummings, V.J.;
 19/03/2025
Title: FAR 2025/17 Annual survey of the Foveaux Strait oyster (Ostrea chilensis) fishery (OYU 5) and Bonamia exitiosa prevalence, intensity, and disease mortality in February 2024
FAR-2025-17-Annual-survey-of-the-Foveaux-Strait-oyster-fishery-OYU5-and-Bonamia-exitiosa-prevalence-intensity-and-disease-mortality-in-February-2024.pdf (5.6 MB)
The Foveaux Strait oyster fishery (OYU 5) is a high value, nationally important fishery. 
A defining feature of the OYU 5 fishery is the recurrent infection by the parasite Bonamia exitiosa (Bonamia)
Annual research surveys monitor both oyster abundance within the fishery and the prevalence of Bonamia infection annually.
A dredge survey was undertaken in February 2024, in collaboration with the Bluff Oyster Management Company Ltd on FV Golden Harvest. 
Oyster densities have declined since 2021.
In 2024, 1755 oysters were tested from 71 stations, with 18.1% testing positive for Bonamia.
The prevalence of infection is higher than in 2023 (8.7%) and the highest it has been since at least 2015. 
The increased prevalence of infection is expected to affect the number of recruit-sized oysters in the population. 
 
ISBN: 978-1-991345-42-4;
ISSN: 1179-5352;
FAR: 2025/17;
AUTHOR: Morrison, M.; Lane, H.S.; Bian, R.; Moss, G.; Brooks, A.; Smith, L.; Forman, J.;
 19/03/2025
Title: FAR 2025/16 Camera, dive, and dredge surveys of scallops in SCA 1 and SCA CS, 2024
FAR-2025-16-Camera-dive-and-dredge-surveys-of-scallops-in-SCA1-and-SCACS-2024.pdf (6.9 MB)
 Scallops (Pecten novaezelandiae) are a species of shellfish that live on the seabed in sandy coastal areas in Aotearoa-New Zealand (NZ). Scallops support highly valued commercial and non-commercial (customary and recreational) fisheries, but fishery closures have been put in place due to sustainability concerns.
 
Scallop populations in northeastern NZ were surveyed in 2024 to assess the status of the scallop beds since the closures were first put in place in 2022. A variety of camera, dive, and dredge survey methods were used to survey the main scallop fishing areas to collect the images and data for analysis.
 
The 2024 survey work included the first use of Artificial Intelligence (AI) in a NZ scallop survey. AI was used to automatically find and measure the size of scallops visible in the photos from the camera survey. The AI method was tested using data collected by the divers. The dredge survey allowed a comparison between the camera and dredge survey methods.
 
The findings of the camera/AI and dredge surveys were similar. The AI correctly identified and measured most of the scallops in the camera survey photos. Future work could further improve this new method.
 
The 2024 survey results showed there had been some localised increases in scallop numbers in Eastern Coromandel and in Whangarei Harbour, but there was no e
ISBN: 978-1-991345-39-4;
ISSN: 1179-5352;
FAR: 2025/26;
AUTHOR: Williams, J.R.; Underwood, M.J.; Rensen, T.; Hughes, R.; Bian, R.; Middleton, C.; Evans, O.; Middleton, I.;
2025/1510/03/2025
Title: FAR 2025/15 Results of the 2022–23 Pāua Catch Sampling project
FAR-2025-15-Results-of-the-2022-23-paua-Catch-Sampling-project.pdf (3.7 MB)
This report summarises pāua shell length information collected by sampling the commercial catch from areas PAU 2, PAU 3A, PAU 3B, PAU 4, PAU 5A, PAU 5B, PAU 5D and PAU 7 during the 2022–23 fishing year.

The length frequency distributions were typical of commercial pāua fisheries, and consistent with previous years.

AUTHOR: Cooper, J.P.; McCowan, T.A.;
2025/1410/03/2025
Title: FAR 2025/14 Assessment of hoki (Macruronus novaezelandiae) in 2024
FAR-2025-14-Assessment-of-hoki-in-2024.pdf (9.9 MB)

 

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 51% of its unfished level for the eastern stock and 41% for the western stock. The combined stock status was estimated to be 45% (two-stock model) or 46% (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.

 

AUTHOR: McGregor, V.L.; Langley, A.D.;
2025/1327/02/2025
Title: FAR 2025/13 Albacore catch sampling during 2021–22 to 2023–24
FAR-2025-13-Albacore-catch-sampling-during-2021-22-to-2023-24.pdf (12.6 MB)
• Albacore are mostly caught by trolling on the west coast of New Zealand. Albacore catch is composed of three distinct sizes in most years, probably reflecting one- to three-year-old fish.
• Albacore caught by trolling during the 202122, 202223, and 202324 fishing seasons were sampled onshore to determine the length frequency composition and length-weight relationship. 
• Albacore were sampled from two ports, in Greymouth and for the first time, in Nelson, New Zealand. The numbers targeted for sampling were based on the commercial catch each month during recent years. Fish were sampled between January and March / April each year.
• Each year roughly 3700 – 4500 fish had their length measured, and approximately 400 fish were weighed. 
• We investigated patterns over space and time of catch and effort. These were different for the three fishing seasons. Sampling captured the patterns of the commercial fishery well.
• The length distribution showed three peaks visible in most samples during 202122 and 202223. In 2023−24 there was only one peak around 62 cm, with few small or large fish.
 
2025/1227/02/2025
Title: FAR 2025/12 New Zealand billfish and gamefish tagging, 2022–23 to 2023–24
FAR-2025-12-New-Zealand-billfish-and-gamefish-tagging-2022-23-to-2023-24.pdf (3.0 MB)
This report outlines the findings of the New Zealand Gamefish Tagging Programme (NZGTP) for the 2022–23 and 2023–24 fishing years. The NZGTP is a cooperative project between Fisheries New Zealand, the New Zealand Sport Fishing Council (NZSFC), its affiliated clubs, and other recreational and commercial fishers.
 
The programme collects data on the tagging and recapture of key gamefish species, including marlin, swordfish, kingfish, and some shark and tuna species, within New Zealand's waters and surrounding areas. Over the last two years, 2049 fish were tagged in New Zealand waters, with an additional 35 tagged internationally.
 
Information collected in this project are used to describe: 
•When each species of fish is available in New Zealand;
•Seasonal migrations; 
•Stock boundaries or management regions
•Growth rates;
•Changes in distribution over time.
 
Striped marlin, one of the main species, was tagged and released in significant numbers, especially in early 2024. Yellowtail kingfish is another important species in the programme and the number tagged and released from commercial vessels has increased. The catch rates for other species, like blue marlin and yellowfin tuna, have varied. The number of tagged sharks has declined, particularly for mako and blue sharks, while bro
AUTHOR: Holdsworth, J.C.; Curtis, S.;
35014/02/2025
Title: AEBR 350 Electronic Automated Reporting System (EARS): Remote at-sea monitoring of seabird bycatch mitigation measures
AEBR-350-2025-Electronic-Automated-Reporting-System-Remote-at-sea-monitoring-of-seabird-bycatch-mitigation-measures.pdf (5.9 MB)
 Methods to reduce and monitor seabird bycatch in tuna longline fisheries are subject to ongoing investigation globally. Proven methods to reduce seabird bycatch are available, while these may not be implemented at sea. This project progressed the development of a working benchtop prototype device designed to monitor deployment of a tori line (a line with streamers attached that is deployed astern the fishing vessel, and reduces the risk of seabird bycatch by deterring birds from attending longline gear during setting), night setting, and the presence of weights on longline branchlines. The benchtop prototype device was transformed into a unit designed for at-sea deployment and subjected to proof-of-concept at-sea testing. The seagoing prototype design incorporated two small IP cameras, a GPS antenna, a rotation sensor, and an externally produced tracking buoy intended to record the location of the terminal end of the tori line. Forty-five hours of camera imagery and associated data were collected from five longline sets during at-sea testing in New Zealand. Tori line deployment could be verified and longline setting time was recorded (relevant to monitoring night-setting). The tracking buoy located at the end of the tori line failed to record GPS information during testing. Therefore, the location of the terminal end of the tori line astern the vessel could not be determined. The project also encountered many logistical difficulties, in part due to taking place at the h
AUTHOR: Carovano, K.; Pierre, J.; Fuller, J.; Cozza, A.; Wealti, M.; Torgersion, E.; Jones, Z.;
34914/02/2025
Title: AEBR 349 Review of New Zealand fur seal (Arctocephalus forsteri) mitigation technology
AEBR-349-2025-Review-of-New-Zealand-fur-seal-mitigation-technology.pdf (4.8 MB)
The New Zealand fur seal faces threats from disease, climate change effects on their prey, and interactions with commercial fishing. This project aimed to identify areas where New Zealand fur seals and fisheries interact and evaluate ways to reduce these interactions, while balancing conservation and fishing needs.
 
In some areas around New Zealand, at different times of the year, hoki, middle depth, southern arrow squid, and southern blue whiting trawl fisheries pose the highest fishery-risk to New Zealand fur seals. Lower risk are shark, flatfish, minor set net fisheries, and the southern bluefin tuna surface longline fishery.
 
A literature review examined potential options to reduce New Zealand fur seal interactions. For trawl fisheries, solutions included a Seal Exclusion Device (optimised for New Zealand fur seals), net binding during shooting, and net constriction during hauling. Acoustic devices, designed to cause a startled response in fur seals, showed promise for set net fisheries. Switching from set net to demersal longlining or potting might also be an option. In surface longline fisheries, covering the catch or using acoustic devices may be a solution, although have not commonly been used for seals and sea lions.
 
Mitigation success varies by target species, fishery, and gear type, so a one-size-fits-all approach is not effective. This study
AUTHOR: Underwood, M.J.; Jones, E.G.; Roberts, J.O.; Wells, R.;
34814/02/2025
Title: AEBR 348 Non-target fish and invertebrate catch and discards in New Zealand southern blue whiting trawl fishery from 2006–07 to 2022–23
AEBR-348-2025-Non-target-fish-and-invertebrate-catch-and-discards-in-New-Zealand-southern-blue-whiting-trawl-fishery-from-2006-07-to-2022-23.pdf (9.3 MB)
 This report provides estimates of non-target catch and discards in the southern blue whiting fishery between 2006–07 and 2022–23 (comprising 12 195 trawls from 30 vessels).
 
Southern blue whiting (SBW) accounted for over 99% of the total estimated catch from all observed tows; with no other species contributing more than 0.2% of this catch. The remainder of the observed catch included ling (534 t), hoki (382 t), hake (275 t), porbeagle (178 t), silver warehou (106 t), silverside (51 t), plus a range of other species caught in small amounts, such as rattails, morid cods, and chondrichthyans.
 
Total estimated annual non-target catch ranged from about 57 t to 341 t, similar to levels for earlier periods from the previous assessment and without any clear indication of increasing or decreasing levels over time.
 
Southern blue whiting made up most of the discards due to gear breakage, malfunction, or net damage. Estimated annual discards of southern blue whiting ranged from 19 t to 272 t and showed a slight decline over time.
AUTHOR: Anderson, O.F.; Edwards, C.T.T.; Finucci, B.;
2025/1114/02/2025
Title: FAR 2025/11 Rapid update for the New Zealand rock lobster (Jasus edwardsii) in CRA 2 in 2024
FAR-2025-11-Rapid-update-for-the-New-Zealand-rock-lobster-CRA2-in-2024.pdf (1.9 MB)
 The red rock lobster supports the most valuable inshore commercial fishery in New Zealand. This fishery has been managed with catch quotas in nine Quota Management Areas (QMAs), which are usually treated as independent populations or stocks.
 
To estimate those quotas, each population is fully assessed every five years, requiring a lot of time and effort by a team of at least five researchers working on the review of the previous stock assessments and data inputs, the processing and addition of new data, and development of a new assessment.
 
Every year, instead of a full assessment, a rapid update assessment is done for some of the stocks that were not assessed that year. A rapid update repeats the previous full assessment model, only updating data inputs, which significantly speeds up the required process to provide advice about stock status in the interim years between full stock assessments.
 
This document describes the operation of the stock assessment rapid update completed in 2024 for CRA 2 which can be used to guide management decisions.
 
For the beginning of the 2024–25 fishing year, red rock lobster in CRA 2 was estimated to be above sustainable levels and projected to be above reference levels in five years under current catch limits.
AUTHOR: Pons, M.; Webber, D.N.; Rudd, M.B.; Starr, P.J.; Roberts, J.;
2025/1014/02/2025
Title: FAR 2025/10 Rock lobster catch and effort data: 1979–80 to 2023–24
FAR-2025-10-Rock-lobster-catch-and-effort-data-1979-80-to-2023-24.pdf (4.1 MB)
 This paper summarises commercial catch and effort statistics for red rock lobsters, which are also known in New Zealand as “crayfish” or “kōura”. The summaries are by the fishing year as set out in the Fisheries Act, with the rock lobster legal fishing year defined as the period 1 April–31 March. The summaries presented in this document cover the period 1 April 1979 to 31 March 2024.
 
There are nine red rock lobster Quota Management Areas (QMAs) that cover all inshore waters of the North Island, the South Island and the Chatham Islands. There are 43 statistical areas that lie within these nine QMAs. The summaries are ordered by QMA, with each QMA identified by a three-letter code and a number. The red rock lobster code is CRA, so the nine QMAs are labelled CRA 1 to CRA 9.
 
The first three tables for each CRA QMA summarise, by statistical area and fishing year, (1) number of vessels, (2) catch and (3) effort. The last category is defined as the total number of rock lobster pots lifted within each fishing year and statistical area. The fourth table summarises catch by month and fishing year for the entire QMA and a fifth table gives the monthly catch by statistical area for just the final fishing year, which is 2023–24 in this document.
 
The sixth table for each QMA summarises catch-per-unit-effort (CPUE) by statist
AUTHOR: Starr, P.J.;
2025/0814/02/2025
Title: FAR 2025/08 Estimates of pāua harvest by land-based amateur fishers—Kaikōura Marine Area in 2024
FAR-2025-08-Estimates-of-paua-harvest-by-land-based-amateur-fishers-Kaikoura-Marine-Area-in-2024.pdf (1.4 MB)
 This report outlines the findings of the 2024 onsite survey estimating the amateur harvest of pāua in the Kaikōura Marine Area, New Zealand. The fishery was closed after the 2016 Kaikōura earthquakes due to significant habitat damage and pāua mortality. Following public consultation and engagement with tangata whenua, the fishery reopened for a three-month open season in summer 2021–22. An onsite survey was designed and implemented to estimate recreational harvest from land-based access points.
 
This report describes the method and results for the third survey of amateur pāua harvest in the Kaikōura Marine Area, covering a 61 day open season from 1 April to 31 June 2024. A roving survey that counted the number of fishers in the water was used to estimate hourly fishing effort. Separate onsite interviews recorded catch per fisher when they had finished fishing. Oaro, south of the main survey area was included for a second year. Interviewers collected individual pāua weight and length from all surveyed catch.
 
Across the 27 survey days, clerks interviewed a total of 353 individual fishers and counted 1074 fishers in the water. The total recreational harvest for all daylight hours and days in the Kaikōura Marine Area was estimated to be 15.83 tonnes (CV 0.18), which is higher than the 2023 harvest estimate.
AUTHOR: Holdsworth, J.C.; Curtis, S.; Neubauer, P.;
2025/0714/02/2025
Title: FAR 2025/07 Estimation of release survival of Patagonian toothfish Dissostichus eleginoides
FAR-2025-07-Estimation-of-release-survival-of-Patagonian-toothfish.pdf (1.9 MB)
 This study estimated the proportion of Patagonian toothfish caught within the New Zealand EEZ that would survive if they were released alive.
 
These survival estimates were based on the available New Zealand and overseas studies and on information from experts, such as fishers, fishery observers, and research scientists.
AUTHOR: Devine, J.; Underwood, M.J.;
2025/0114/02/2025
Title: FAR 2025/01 Stock assessment and spawning potential ratio-based management procedures for pāua (Haliotis iris) fisheries in PAU 3A
FAR-2025-01-Stock-assessment-and-management-procedures-for-paua-fisheries-in-PAU3A.pdf (6.3 MB)
Stock assessments support the sustainable management of fisheries resources, such as pāua, throughout New Zealand. This study assessed pāua stocks in the area around Kaikōura, which was affected by the 2016 earthquake (now quota management area PAU 3A). The current project aimed to assess the status and management options for pāua stocks there by developing stock assessment models for pāua. The models were informed by fisheries, biological and survey data, and performed well based on data from the periods before and after the earthquake. Although there were some uncertainties about the representativeness of the survey data and about recreational take of pāua, the modelling estimated that the pāua stock in PAU 3A was at or above target levels in 2023. In addition, this study also evaluated management strategies for supporting sustainable pāua fisheries following the earthquake. This part of the study considered different limitations, known as harvest control rules, for pāua fisheries in this area. Different scenarios of limitations were assessed, associated with reproductive output of pāua. Based on the exploration of different strategies, the harvest control rules proposed here indicated that their implementation would maintain the PAU 3A fishery in a healthy state.
AUTHOR: Neubauer, P.; Kim, K.; Amar, T.; Prince, J.;
35114/02/2025
Title: AEBR 351 Marine heatwaves and fisheries in Aotearoa New Zealand: observed and projected temperature anomalies and potential impacts by fisheries management area
AEBR-351-2025-Marine-heatwaves-and-fisheries-in-Aotearoa-New-Zealand.pdf (19.3 MB)
The ocean around Aotearoa New Zealand has been warming, and marine heatwaves have become more prevalent and more intense.
This project examines patterns in warming (the slow warming trend over time) and heatwaves (shorter periods that are exceptionally warm) around Aotearoa New Zealand.
 
Maps of past and future projected coastal and ocean temperatures are reported for “shallow” (0–200 m) and “deep” (200–1500 m) waters in the ten Aotearoa New Zealand Fisheries Management Areas.
 
Most coastal waters show a sea surface warming trend between 0.2–0.3°C per decade.
 
Coastal bottom temperatures are warming by about 0.1°C per decade.
 
Marine heatwaves are projected to get hottest around the North Island, and more frequent around the South Island.
 
The fish stocks more likely to be impacted by future temperature changes include: green-lipped mussels on the west coast of the North Island; pelagic mackerels and tunas around the North Island and the west coast of the South Island; pāua around the Chatham Islands; snapper and John dory around the North Island and the west coast of the South Island; and arrow squid off Southland and northern parts of the Sub-Antarctic.
 
We recommend these regions and fisheries would benefit from further and more d
AUTHOR: Behrens, E.; Dunn M.R.; Holmes, S.J.; Cummings, V.J.;
2025/0914/02/2025
Title: FAR 2025/09 Commercial Catch sampling programme for Highly Migratory Species in 2021–22, 2022–23, and 2023–24
FAR-2025-09-Commercial Catch-sampling-programme-for-Highly-Migratory-Species-in-2021-22-2022-23-and-2023-24.pdf (7.7 MB)
 Kendrick, T.H. (2025). Commercial Catch sampling programme for Highly Migratory Species in 2021–22, 2022–23, and 2023–24. New Zealand Fisheries Assessment Report 2025/09. 34 p.
 
Swordfish and tunas caught by tuna longline vessels are processed at sea, preventing the measurement of lengths in port samples, but individual processed weights of the catch are kept by those fish processors that export, in a relatively whole state, these large and valuable fish. Processed weights can be converted to lengths so that this project effectively augments observer length frequency data with estimates based on individual processed weights of fish landed by the domestic fleet.
AUTHOR: Kendrick, T.H.;
2025/0614/02/2025
Title: FAR 2025/06 Trevally characterisation and CPUE for TRE 1 to 2021–22 and TRE 2 to 2020–21
FAR-2025-06-Trevally-characterisation-and-CPUE-for-TRE1-to-202122-and-TRE2-to-202021.pdf (11.7 MB)
The objective of this work was to update catch histories and data series for the trevally (TRE 1) stock assessment. This included investigating alternative stock hypotheses and whether incorporating water clarity data might improve bottom trawl catch-per-unit-effort model fits.
 
Trevally in the East Northland – Hauraki Gulf region are now believed to be of the same stock, and preference of the west or east of the Northland region is likely driven by an environmental factor. Incorporating water clarity did not improve the model for the East Northland – Hauraki Gulf region.
 
Trevally in the Bay of Plenty and TRE 2 are thought to be mixing, but the available data could not define the spatial or temporal extent of that mixing. The accepted CPUE index for this region was based solely on the Bay of Plenty.
AUTHOR: Devine, J.; Holmes, S.J.; Bian, R.; McKenzie, J.; Hoyle, S.;
2025/0514/02/2025
Title: FAR 2025/05 Catch-at-age for barracouta (Thyrsites atun) in BAR 5 and gemfish (Rexea solandri) in SKI 3 and SKI 7 for the 2022–23 fishing year
FAR-2025-05-Catch-at-age-for-BAR5-and-SKI3-and-SKI7-for-the-2022-23-fishing-year.pdf (933.9 kb)
 Catch-at-age data are important for stock assessment because they provide information on the strength and progression of age classes in the stock. These data include information on the length and age, from otoliths (the ear bones of fish), collected at sea by observers from the commercial catch.
 
This report provides estimation of catch-at-age from the bottom trawl fisheries for barracouta (Thyrsites atun, BAR) in BAR 5 (Southland) and for gemfish (Rexea solandri, SKI) in SKI 3 (southeast coast) and SKI 7 (Challenger) for the 2022–23 fishing year. These results are the third of a three-year catch-at-age series for these two species.
 
Most of the barracouta were aged 2–5 years and strong and weak cohorts could be tracked across years.
 
Gemfish from SKI 3 in the 2022–23 fishing year indicated that a large number of age 2 fish were present, but that the age 3 cohort was missing. Ageing error was not thought to explain this discrepancy.
 
Female gemfish from SKI 7 were generally larger (and older) than males in the bottom trawl catch, and a large number of fish under the age of 3 were present. Augmenting the 2020–21 data with information on smaller (younger) fish from the 2021 West Coast South Island trawl survey added information for fish aged 0–2.
AUTHOR: Devine, J.A.; Sutton, C.; Hart, A.; Spong, K.;
2025/0414/02/2025
Title: FAR 2025/04 Recreational harvest of southern bluefin tuna in New Zealand, 2023–24
FAR-2025-04-Recreational-harvest-of-southern-bluefin-tuna-in-New-Zealand-2023-24.pdf (810.3 kb)

We estimate the annual recreational catch of southern bluefin tuna in New Zealand for the 2023–24 October fishing year. This information helps meet the obigation to report all of New Zealand’s catch of this species to the Commission for Conservation of Southern Bluefin Tuna each year.

Tuna numbers and weights are collected from a number of sources including:

  • sportfishing club weigh station records;
  • a monthly telephone survey of South Island fishers;
  • catch records from online reporting on the fishcatch.co.nz web page;
  • catch records from recreational charter boats;
  • records of recreational catch taken from commercial vessels for personal use; and
  • boat ramp interviews at Waihau Bay in the eastern Bay of Plenty (where most of the recreational catch is landed).

The estimated 2024 recreational harvest of southern bluefin tuna is 992 individual fish, which is fewer than in 2023 (1241 fish).

The estimated total landed weight for the recreational fishery is between 65 and 73 tonnes with a mid-point of 69.5 tonnes.

AUTHOR: Holdsworth, J.C.;
2025/0314/02/2025
Title: FAR 2025/03 Stock assessment of hake (Merluccius australis) off the West Coast South Island (HAK 7) for the 2023–24 fishing year
FAR-2025-03-Stock-assessment-of-HAK7-for-the-2023-24-fishing-year.pdf (7.2 MB)
 This report provides a stock assessment of the west coast South Island stock of hake (HAK 7 off the west coast of New Zealand) up to the end of the 2023–24 fishing year. The index of abundance provided to the model was the west coast South Island Tangaroa trawl survey series and this was combined with fishery and survey age composition data to model the population.
 
Initial spawning stock biomass (SSB) was estimated at 75 480 t (70 830–81 830) with current SSB 47% B0 (34–67% B0). The model was sensitive to assumptions about recent and future year class strengths. If we assume lower recruitment for years after 2017 (at the 2008–2017 level), the current SSB is estimated as 39% B0 (23–50% B0).
AUTHOR: Dunn, A.;
2025/0214/02/2025
Title: FAR 2025/02 Developments in scampi surveys: 2023–24
FAR-2025-02-Developments-in-scampi-surveys-202324.pdf (910.7 kb)
This report describes two separate pieces of work done in 2023–24 to improve the way scampi surveys are included in stock assessment models.
 
Scampi build and live in burrows made from the sediment in their environment. One of the ways scampi stocks have been assessed historically is with a series of photo surveys where the number of burrow entrances in a series of photos are counted by photo ‘readers’. There can be variability between readers in interpretation of bottom features as burrows. An individual reader’s interpretation can also ‘drift’ over time. A way to test for differences in interpretation between readers and for ‘reader drift’ was developed so that the burrow count indices could be properly calibrated.
 
In 2019, this calibration methodology was updated but when it was applied to later surveys there were large and unexpected adjustments which undermined confidence in the method. This report outlines the design for a simulation framework that could test whether the calibration method is performing as intended. 
 
When an abundance index is used in a stock assessment model a catchability (labelled q) converts the numbers in the index to numbers in the population. These q values are estimated within the model, but the model uses ‘prior’ information about what values of q are considered reasonable. These prior
AUTHOR: Holmes, S.J.; McGregor, V.L.; Underwood, M.J.; Wieczorek, A.M.;
2024/8725/11/2024
Title: FAR 2024/87 Inshore trawl survey of Canterbury Bight and Pegasus Bay, April–June 2024 (KAH2402)
FAR-2024-87-Inshore-trawl-survey-of-Canterbury-Bight-and-Pegasus-Bay-April-June-2024-KAH2402.pdf (9.4 MB)
This report presents results from the 15th east coast South Island inshore trawl survey in 2024, which continues a time series started in 1991.

The survey series covers the area from Waiau River to Shag Point, at depths from 30 to 400 metres (core strata), and estimates biomass for many species but is optimised for the target species: dark ghost shark, giant stargazer, red cod, spiny dogfish, sea perch, and tarakihi. Since 2007, four strata in depths from 10 to 30 m have been included in the survey to better cover the depth range of elephantfish and red gurnard, which were added as target species.

Data collected include length, weight, and maturity data for selected species, and collection of otoliths (fish ear stones) of the key species for ageing. The trawl survey provides time series of relative biomass estimates and age, length, and maturity stage information used for stock assessments and fisheries management advice for key inshore species.

In 2024, 106 stations were successfully carried out. Almost all target and key non-target QMS species in 2024 declined in biomass from 2022, several of them substantially. For red cod, sea perch, and tarakihi, biomass estimates were the lowest in the time series, and for spiny dogfish, barracouta, lemon sole, and ling, estimates were the second lowest in the ser
AUTHOR: MacGibbon, D.J.0F; Beentjes, M.P.; Escobar-Flores, P.;
2024/0215/11/2024
Title: FSR 2024/02 2009 Expert Review Panel Report - Review of blue cod potting survey in New Zealand
FSR-2024-02-2009-Expert-Review-Panel-Report-Review-of-blue-cod-potting-survey-in-New-Zealand.pdf (668.3 kb)
 The New Zealand Ministry of Fisheries (MFish) convened a review of New Zealand blue cod potting surveys on 16 and 17 April  2009.  The review included: presentations by Expert Panel members about potting surveys; presentations by the scientists working on the New Zealand blue cod potting surveys; questions and discussion about the blue cod surveys; and conclusions from the Expert Panel.  This report summarises the conclusions of the Expert Panel, relative to the Panel terms of reference.
 
 
 
This review occurred before the Fisheries Science Review series began, so it is being published retrospectively, to make the information (which is still relevant to blue cod science) more easily available.
AUTHOR: Stephenson, P.; Sedberry, G.; Haist, V.;
2024/8415/11/2024
Title: FAR 2024/84 The 2024 stock assessment of ling (Genypterus blacodes) in the Sub-Antarctic (LIN 5&6 and LIN 6B)
FAR-2024-84-2024-stock-assessment-of-ling-in-the-Sub-Antarctic.pdf (4.3 MB)
 Ling (Genypterus blacodes) is an important commercial fish species in New Zealand middle depths waters and is caught mainly by bottom trawls, bottom longlines, and increasingly by potting.
 
This report summarises the 2024 stock assessment of one of the five main ling stocks managed under the Quota Management System: the Sub-Antarctic ling stock, defined as LIN 5&6 and including LIN 6B for the first time.
 
A stock assessment model was carried out, informed by commercial catches, commercial age compositions, and information from the Sub-Antarctic Tangaroa trawl survey biomass series.
 
The initial spawning stock biomass (B0) for both the base case model was estimated to be about 204 630 t and stock status in 2024 was estimated at 66% B0.
 
Five-year projections were done using the base case model, assuming various future recruitment and annual catch options. Projected stock status in 2029 was expected to be above the target of 40% B0 in all instances, however the exploitation rate in LIN 5 was expected to exceed the target exploitation rate if the catch in LIN 5 was increased by more than 20%.
AUTHOR: Mormede, S.; Dunn, A.; Webber, D.N.;
2024/8315/11/2024
Title: FAR 2024/83 Stock hypothesis for ling in the Sub-Antarctic (LIN 5&6 and LIN 6B)
FAR-2024-83-Stock-hypotheses-for-ling-in-the-Sub-Antarctic.pdf (2.8 MB)
 Ling (Genypterus blacodes) is an important commercial fish species in New Zealand middle depths waters and is caught mainly by bottom trawls, bottom longlines, and increasingly by potting.
 
This report investigates various stock hypotheses for in the Sub-Antarctic ling. Differences in growth suggested that LIN 3&4, LIN 5&6, and LIN 7WC were likely to be different stocks and that the current boundaries between those stocks were likely to be adequate. Catch rates, age structure, and growth data suggested that LIN 6B was unlikely to be part of LIN 3&4, with weak evidence that it was part of LIN 5&6.
 
Because of the paucity of data available to assess LIN 6B as a separate stock, and the similarities in the information between LIN 5&6 and LIN 6B, the Fisheries New Zealand Deepwater Working Group decided to include LIN 6B with LIN 5&6 as a single Sub-Antarctic ling stock (LIN 5&6 and LIN 6B) for the 2024 stock assessment of Sub-Antarctic ling.
AUTHOR: Mormede, S. Dunn, A.; Webber, D.N.;
2024/8215/11/2024
Title: FAR 2024/82 Descriptive analysis of ling in the Sub-Antarctic (LIN 5&6 and LIN 6B) up to 2023 and inputs for the 2024 stock assessment
FAR-2024-82-Descriptive-analysis-of-ling-in-the-Sub-Antarctic-up-to-2023-and-inputs-for-the-2024-stock-assessment.pdf (12.2 MB)
 Ling (Genypterus blacodes) is an important commercial fish species in New Zealand middle depths waters and is caught mainly by bottom trawls, bottom longlines, and increasingly by potting.
 
This report summarises the 2024 characterisation of one of the five main ling stocks managed under the Quota Management System: Sub-Antarctic ling (LIN 5&6 and LIN 6B). The Total Allowable Commercial Catch (TACC) in LIN 5&6 is generally caught whilst that in LIN 6B has not been caught since 2005.
 
The bottom longline standardised catch per unit effort (CPUE) was updated for LIN 5&6 and for LIN 6B. Spatio-temporal CPUE indices were also developed and were in general agreement with the non-spatially explicit CPUE indices.
 
Length-weight relationships, von Bertalanffy growth curves, and maturity curves were updated for LIN 5&6. The maturity ogive for LIN 5&6 indicated some level of inter-annual variability. Only von Bertalanffy growth curves were updated for LIN 6B due to the paucity of data.
 
Inputs to the 2024 stock assessment of Sub-Antarctic ling are summarised.
AUTHOR: Mormede, S.; Dunn, A.; Webber, D.N.;
2024/8115/11/2024
Title: FAR 2024/81 Estimation of shellfish release survival from New Zealand commercial fisheries
FAR-2024-81-Estimation-of-shellfish-release-survival-from-New-Zealand-commercial-fisheries.pdf (6.5 MB)
This study estimated the survival of four shellfish species (scallops, queen scallops, paddle crabs, and sea cucumbers), when returned to the sea after being caught in New Zealand commercial fisheries. For species such as scallops with a minimum legal size (MLS), those below the MLS must be returned dead or alive, while for others such as sea cucumbers, their release is dependent not on size but on being alive and considered likely to survive (destination type code X). Estimates are based on previous local research, or studies with similar species overseas, along with responses to a questionnaire from fishers and fisheries managers with direct observations of immediate or at-release survival, and researchers with knowledge on post-release or longer-term survival. This information was analysed along with reported fishery data on how the shellfish returned to the sea were caught (such as dredge tow duration, speed, and catch size), to provide a range of likely survival estimates for each species and gear combination (differences between target and non-target fisheries are mainly due to differences in durations, speeds, catch sizes and/or seasons):

For New Zealand scallops, the survival estim
AUTHOR: Johnson, K.S.; Jordan, L.K.; McKenzie, J.R.; Bian, R.; Williams, J.R.; Underwood, M.J.; Morrison, M.A.;
2024/8015/11/2024
Title: FAR 2024/80 Commercial catch sampling for species proportion, sex, length, and age of jack mackerels in JMA 7 in the 2022–23 fishing year, with a summary of all available data sets
FAR-2024-80-Commercial-catch-sampling-of-jack-mackerel-JMA7-in-the-2022-23-fishing-year.pdf (4.0 MB)
 Jack mackerels support significant commercial fisheries in New Zealand, with over 75% of the total jack mackerel catch taken by trawl fisheries off the west coasts of the North Island and South Island, in the JMA 7 Quota Management Area. Three jack mackerel species are caught in New Zealand waters (Trachurus declivis, T. murphyi, and T. novaezelandiae) but commercial catches of jack mackerels are only recorded against the generic species code JMA. Therefore, species-specific catch information is not available from the fishery data. Estimates of proportions of the three Trachurus species in the catch, based on species code specific observer data are used to derive species-specific catch estimates from the JMA catch data.
 
This report updates the data collected by the New Zealand observer sampling programme from trawl landings of jack mackerels in JMA 7 with the data collected during the 2022–23 fishing year, including estimates of species proportions and the ratio of males and females in the landings, as well as the numbers caught by length and age.
 
Estimated proportions of catch by species based on observer data have historically shown that T. declivis comprises 61–73% of the catch for all statistical areas, followed by T. novaezelandiae at 21–33%, and T. murphyi at 2–8%. In 2022–23, proportions of T. declivis, T. novaezelandiae, and T. murphyi wer
AUTHOR: Moore, B.R.; Ó Maolagáin, C.; Spong, K.;
2024/7915/11/2024
Title: FAR 2024/79 Relative abundance, size and age structure, and stock status of blue cod off Motunau in 2024
FAR-2024-79-Relative-abundance-size-and-age-structure-and-stock status-of-blue-cod-off-Motunau-in-2024.pdf (2.5 MB)
 South Island recreational blue cod (Parapercis colias) fisheries are monitored by Fisheries New Zealand using potting surveys. This report describes the results of the blue cod potting survey carried out off Motunau in North Canterbury during January 2024 – as well as for three previous surveys (2012, 2016, 2020). Estimates are provided for population abundance, size structure from fish length, and age structure from otoliths (ear bones collected for ageing), as well as population sex ratio, total mortality, and fishing mortality. In 2024 the sex ratio was 74% male, and the estimated fishing mortality was nearly four times the target reference level indicating that overfishing is occurring. Survey mean catch rates showed a progressive decline over time, dropping by 66% between 2012 and 2024. The sex ratio over the four surveys was dominated by males with no trend (i.e., 72–76% male). Fishing pressure has been concentrated on just a few older ages, and was considerably higher than the target reference for all the previous surveys.
AUTHOR: Beentjes, M.P.; Miller, P.;
34715/11/2024
Title: AEBR 347 Continuous Plankton Recorder sampling of zooplankton and microplastic in the Southern Ocean 2002 to 2023 with special focus on the Ross Sea sector
AEBR-347-2024-Continuous-Plankton-Recorder-sampling-of-zooplankton-and-microplastic-in-the-Southern-Ocean-2002-to-2023.pdf (7.3 MB)
This report summarises data collected in the third phase of the 15-year project to sample zooplankton and microplastic between New Zealand and the Ross Sea, Antarctica. We also analyse the full international dataset (1991–2023). Samples were collected in the project by towing the Continuous Plankton Recorder (CPR) behind the fishing vessel San Aotea II, during transits between Lyttelton and the Ross Sea.
 
 
 
Key findings:
 
1.   The Ross Sea region is unusual: Consistent with previous work, this project has showed that zooplankton are more abundant in the Ross Sea sector than generally in the rest of the Southern Ocean.
 
 
 
2.   Zooplankton are changing: Overall, we found a decreasing trend in total zooplankton abundance in the Ross Sea sector between 2008 and 2023. There are many different species of zooplankton and these did not all change in the same way over time, and some increased in abundance over the last 15 years.
 
 
 
3.   Plastics are increasing: Our analysis has shown that average plastic abundance has increased 11-fold in the Ross Sea sector between 2009 and 2023, with 99% of the samples from the last 5 years containing at least one microplastic. Most of the plastics were micro
AUTHOR: Pinkerton, M.H.; Halfter, S.; Stewart, R.; Robinson, K.V;
2024/8615/11/2024
Title: FAR 2024/86 Management strategy evaluation of New Zealand ling stocks
FAR-2024-86-Management-strategy-evaluation-of-New-Zealand-ling-stocks.pdf (2.2 MB)
Ling (Genypterus blacodes) is an important commercial fish species in New Zealand middle depths waters and is caught mainly by bottom trawls, bottom longlines, and increasingly by potting.
 
This report summarises the management strategy evaluation of the three main ling stocks: the Chatham Rise (LIN 3&4), Sub-Antarctic (LIN 5&6 and LIN 6B) and the west coast of the South Island (LIN 7WC).
 
Results showed that the projected stock status was mostly affected by the assumptions of natural mortality and future recruitment. The different parameterisations of the harvest control rule had little effect. All simulations maintained biomass above the soft limit.
 
A potential target range was developed for ling, at 33–50% of initial biomass. Under such a target range, only a small subset of simulations would not achieve 50% probability of being above the lower end of target range.
ISBN: 978-1-991330-34-5;
ISSN: 1179-5352;
FAR: FAR 2024/86;
AUTHOR: Mormede, S.;
2024/7815/11/2024
Title: FAR 2024/78 Relative abundance, size and age structure, and stock status of blue cod off Kaikōura in 2023
FAR-2024-78-Relative-abundance-size-and-age-structure-and-stock-status-of-blue-cod-off-Kaikoura-in-2023.pdf (2.8 MB)
 South Island recreational blue cod fisheries are monitored by Fisheries New Zealand using potting surveys. The results of the Kaikōura surveys are important for assessing the status of the blue cod stock in this region.
 
This report describes the results of the random-site blue cod potting survey carried out in Kaikōura in December 2023 and compares these with the four previous surveys.
 
The length frequency distributions and mean length were generally similar among the five surveys. Survey mean catch rates show a progressive decline over time, dropping by 49% between 2011 and 2023. The sex ratio over the surveys was 47–60% male with indications that males are becoming more common in the population. The estimated fishing mortality (F) in 2023 was nearly double the target reference of F = 0.15 indicating that overfishing is occurring.
 
The catch rates of blue cod caught in the Hikurangi Marine Reserve over three surveys (2017, 2019 and 2023) indicate that abundance has not changed much over this period, and while greater than adjacent strata, abundance was only about one quarter of that in other parts of the survey area outside the reserve. Size of fish in the Marine Reserve was also not larger than in other parts of the survey area, but blue cod were of better condition.
AUTHOR: Beentjes, M.P.; Page, M.;
 15/11/2024
Title: FAR 2024/85 Longline observer data coverage in ling fisheries and their use in stock assessments
FAR-2024-85-Longline-observer-data-coverage-in-ling-fisheries-and-their-use-in-stock-assessments.pdf (10.7 MB)
Ling (Genypterus blacodes) is an important commercial fish species in New Zealand middle depths waters and is caught mainly by bottom trawls, bottom longlines, and increasingly by potting.
 
On board cameras will be rolled out on all bottom longline vessels in December 2024, which is expected to lead to a reduction in the collection of biological samples that are used in ling stock assessments. This report investigates the observer coverage of the ling fisheries to date and the potential effect of the loss of longline observer data on the stock assessments.
 
Observer coverage has typically been lower for bottom longline vessels than trawl vessels, and less representative of the fishery. The bottom longline observer data was the most influential for the stock assessment of LIN 3&4 Removing bottom longline data in the assessment model of this stock resulted in a different estimate of biomass and status of the stock, highlighting the importance of these data to inform the stock assessment.
 
For the other ling stocks, the removal of the bottom longline data from the model did not result in a marked changed, possibly due to a lack of adequate observer coverage of these stocks. An increase in observer coverage may lead to a better-informed stock assessment and potentially different understanding of the status of these stocks.
 
T
ISBN: 978-1-991330-33-8;
ISSN: 1179-5352;
FAR: FAR 2024/85;
AUTHOR: Mormede, S.; S. Dunn, A; Webber, D.;
2024/7705/11/2024
Title: FAR 2024/77 Trawl survey of hoki and middle depth species on the Chatham Rise, January 2024 (TAN2401)
FAR-2024-77-Trawl-survey-of-hoki-and-middle-depth-species-on-the-Chatham-Rise-January-2024-TAN2401.pdf (6.0 MB)

The 28th trawl survey in a time series to estimate the abundance of hoki and other species on the Chatham Rise was carried out from 4 January to 3 February 2024. A total of 131 bottom trawls were successfully completed.
The estimated abundance of all hoki was about the same as the estimate from the previous survey in January 2022, while the estimate of juvenile (2 year old) hoki was average for the time series. The estimate of the youngest (1 year old) hoki was one of the lowest in the time series, suggesting this year class (fish born in 2022) was weak. The estimated abundance of hake increased by 26.5% from that in 2022 and was the highest estimate since 2009. The abundance of ling was about the same as in 2022 and the time series for ling shows no overall trend.

Most hoki were aged less than 5 years. Hake and ling ages were broad, with most hake aged between 4 and 13 years and most ling between 3 and 16 years old.

Acoustic data were collected throughout the trawl survey. The acoustic estimate of mesopelagic fish abundance (thought to be an index of the amount of food available to hoki) in 2024 was 13% lower than that in 2022, and below the average for the acoustic time-series (since 2001).

AUTHOR: Stevens, D.W.; Ballara, S.L.; Maurice, A.; Escobar-Flores, P.C.; Yeoman, J.;
34630/10/2024
Title: AEBR 346 A quantitative assessment of mussel nursery site performance
AEBR-346-2024-A-quantitative-assessment-of-mussel-nursery-site-performance.pdf (1.2 MB)

Individual batches of mussel spat were split among eight marine farms to assess whether any appear to be better for spat retention and growth.

 

By splitting single batches of spat we reduced some of variability in spat condition and seeding practices that can make it difficult to determine good farms for growing spat.

 

We found that one farm was better for spat retention than all the others and one farm produced bigger spat.

 

Prior to the spat deployment, each of the eight farms had been graded by mussel farmers as being good, average or poor for spat retention. We found that spat on farms that were predicted to be poor for their retention and growth performed similarly to the good sites. This suggests that it might be possible to grow spat successfully at previously overlooked farms. Further deployments of spat will be used to verify these findings.

AUTHOR: South, P.M.; Delorme, N.J.; Ragg, N.L.C.; Taylor, D.I.;
34530/10/2024
Title: AEBR 345 Post-release survival for leatherback turtles caught in New Zealand surface longline fisheries
AEBR-345-2024-Post-release-survival-for-leatherback-turtles-caught-in-New-Zealand-surface-longline-fisheries.pdf (1.5 MB)
 The Critically Endangered and declining population status of the Western Pacific leatherback turtle population makes it important to quantify the post-release survival for leatherback turtles caught in surface longline fisheries in New Zealand.
 
This report summarises information on at-vessel and post-release survival for leatherbacks globally.
 
Two workshops were conducted during this project, to better understand the New Zealand surface longline fishery and to agree to a scoring scheme for estimating leatherback post-release mortality.
 
Post-release survival for leatherbacks caught in the New Zealand surface longline fishing fleet was estimated to be about 78%. This estimate was based upon 23 interactions.
AUTHOR: Finucci, B.; Dunn, M. R.;
2024/7225/10/2024
Title: FAR 2024/72 Characterisation, standardised CPUE, and assessment input data for scampi (Metanephrops challengeri) at the Auckland Islands (SCI 6A) for 1989–90 to 2022–23
FAR-2024-72-Characterisation-standardised-CPUE-and-assessment-input-data-for-scampi-at-the-Auckland Islands-SCI6A-for-1989-90-to-2022-23.pdf (9.7 MB)
 Fisheries characterisations allow fisheries managers to understand if changes have taken place in the way a stock is being fished or if any other factors suggest a need for research or management attention.
 
A standardised Catch-Per-Unit-Effort (CPUE) index is a time series of catch per unit of fishing effort, modified or ‘standardised’ to account for changes in ‘fishing power’ or other factors; e.g., because of changes in fishing vessels, or the type of fishing gear deployed, or the seasonal timing of the fishery. Standardised CPUE can provide a proxy for the relative abundance of the stock, and this can be a valuable source of information for quantitative assessments that provide estimates of the stock’s size and status.
 
This report presents a characterisation for the scampi stock located near the Auckland Islands (SCI 6A) and a standardised CPUE index for that stock. It also details biological and other inputs necessary for a quantitative assessment of the stock.
 
The SCI 6A fishery developed in the early 1990s. Up to the early 2000s fishing was focused between January and May, but with some activity throughout the year. Since the introduction of scampi into the quota management system (QMS) in October 2004 the focus shifted more towards June to September with very little trawling between December and February, whic
AUTHOR: Holmes, S.J.; McGregor, V.L.;
2024/7625/10/2024
Title: FAR 2024/76 Assessment modelling of scampi (Metanephrops challengeri) at the Auckland Islands (SCI 6A) in 2024
FAR-2024-76-Assessment-modelling-of-scampi-at-the-Auckland-Islands-SCI6A-in-2024.pdf (4.7 MB)
 Integrated stock assessments provide estimates of stock status based on all 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 model for scampi in the Auckland Islands (SCI 6A) that was not accepted by the Fisheries New Zealand Deepwater Working Group for the assessment of this stock. It includes information on the biology of scampi and data from commercial fisheries and research surveys. The model used two annual time-steps to reflect changes in vulnerability of males and females as moulting occurs at different times. Key concerns with the model were on the input data and suggest more work is required to understand inconsistencies within and between the datasets.
ISBN: 978-1-991330-14-7;
ISSN: 1179-5352;
FAR: 2024/76;
Author: McGregor, V.L.; Holmes, S.J.;
2024/7521/10/2024
Title: FAR 2024/75 Final Report for a Community Based Shellfish Monitoring Frameworks Project
FAR-2024-75-Final-report-for-a-Community-Based-Shellfish-Monitoring-Frameworks-Project.pdf (4.2 MB)

This report covers a Community Based Shellfish Monitoring pilot project. This project was undertaken to test whether community groups could safely undertake shellfish monitoring by freediving and to build a set of resources to help other community groups start their own monitoring programmes. Ultimately, the goal is to enable better management decisions moving forward for shellfish in Aotearoa. The report includes:

  • A set of results from trialling monitoring as an activity carried out by young Māori
  • An overview of partnerships that were key to the success of the project.
  • Links to a set of resources that can be copied and adapted for community groups to use anywhere in the country, to monitor ten different types of shellfish.
AUTHOR: Guccione D.G.; Judd S.J;
2024/7421/10/2024
Title: FAR 2024/74 Catch-at-age from commercial fisheries for hake (Merluccius australis) and ling (Genypterus blacodes) in 2022–23 and a trawl survey in 2024
FAR-2024-74-Catch-at-age-from-commercial-fisheries-for-hake-and-ling-in-2022-23-and-a-trawl-survey-in-2024.pdf (10.0 MB)
This report provides catch-at-age for hake (Merluccius australis) and ling (Genypterus blacodes) from commercial fisheries during the 2022–23 (2023) fishing year and a research trawl survey in January 2024, to update ongoing time series.
 
These estimates are based on biological data and otoliths (ear bones used for ageing fish) sampled by observers and survey staff. The sampled ages are extrapolated via broader fishery or survey information (length frequencies scaled to total catch or survey biomass) to form a representative estimate of catch-at-age.
 
Catch-at-age estimates of exploited stocks are important for stock assessment and management because they provide information on the selectivity of fishing gear, magnitude of a given year class, and productivity (i.e. growth rate, age at reproduction, and natural mortality).
 
In order to improve the precision of the hake and ling catch-at-age estimates in the future, increased observer sampling of hake and ling biological data and otoliths, in key areas and times would be required.
AUTHOR: Ballara, S.L.; Barnes, T.C.; Hart, A.; Sutton, C.; Ó Maolagáin, C.; Spong, K.;
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