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Document library
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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2547 items (1 to 50 shown)
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| | 19/03/2025 |
• 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.
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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.;
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| | 19/03/2025 |
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
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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.;
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| 2025/15 | 10/03/2025 |
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.
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AUTHOR:
Cooper, J.P.;
McCowan, T.A.;
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| 2025/14 | 10/03/2025 |
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.
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AUTHOR:
McGregor, V.L.;
Langley, A.D.;
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| 2025/13 | 27/02/2025 |
• 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 202122, 202223, and 202324 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 202122 and 202223. In 2023−24 there was only one peak around 62 cm, with few small or large fish.
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| 2025/12 | 27/02/2025 |
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
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AUTHOR:
Holdsworth, J.C.;
Curtis, S.;
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| 350 | 14/02/2025 |
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
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AUTHOR:
Carovano, K.;
Pierre, J.;
Fuller, J.;
Cozza, A.;
Wealti, M.;
Torgersion, E.;
Jones, Z.;
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| 349 | 14/02/2025 |
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
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AUTHOR:
Underwood, M.J.;
Jones, E.G.;
Roberts, J.O.;
Wells, R.;
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| 348 | 14/02/2025 |
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.
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AUTHOR:
Anderson, O.F.;
Edwards, C.T.T.;
Finucci, B.;
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| 2025/11 | 14/02/2025 |
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.
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AUTHOR:
Pons, M.;
Webber, D.N.;
Rudd, M.B.;
Starr, P.J.;
Roberts, J.;
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| 2025/10 | 14/02/2025 |
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
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AUTHOR:
Starr, P.J.;
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| 2025/08 | 14/02/2025 |
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.
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AUTHOR:
Holdsworth, J.C.;
Curtis, S.;
Neubauer, P.;
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| 2025/07 | 14/02/2025 |
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.
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AUTHOR:
Devine, J.;
Underwood, M.J.;
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| 2025/01 | 14/02/2025 |
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.
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AUTHOR:
Neubauer, P.; Kim, K.; Amar, T.; Prince, J.;
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| 351 | 14/02/2025 |
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
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AUTHOR:
Behrens, E.;
Dunn M.R.;
Holmes, S.J.;
Cummings, V.J.;
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| 2025/09 | 14/02/2025 |
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.
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AUTHOR:
Kendrick, T.H.;
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| 2025/06 | 14/02/2025 |
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.
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AUTHOR:
Devine, J.;
Holmes, S.J.;
Bian, R.;
McKenzie, J.;
Hoyle, S.;
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| 2025/05 | 14/02/2025 |
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.
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AUTHOR:
Devine, J.A.;
Sutton, C.;
Hart, A.;
Spong, K.;
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| 2025/04 | 14/02/2025 |
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.
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AUTHOR:
Holdsworth, J.C.;
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| 2025/03 | 14/02/2025 |
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).
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AUTHOR:
Dunn, A.;
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| 2025/02 | 14/02/2025 |
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
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AUTHOR:
Holmes, S.J.;
McGregor, V.L.;
Underwood, M.J.;
Wieczorek, A.M.;
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| 2024/87 | 25/11/2024 |
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
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AUTHOR:
MacGibbon, D.J.0F;
Beentjes, M.P.;
Escobar-Flores, P.;
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| 2024/02 | 15/11/2024 |
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.
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AUTHOR:
Stephenson, P.;
Sedberry, G.;
Haist, V.;
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| 2024/84 | 15/11/2024 |
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%.
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AUTHOR:
Mormede, S.;
Dunn, A.;
Webber, D.N.;
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| 2024/83 | 15/11/2024 |
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.
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AUTHOR:
Mormede, S. Dunn, A.;
Webber, D.N.;
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| 2024/82 | 15/11/2024 |
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.
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AUTHOR:
Mormede, S.;
Dunn, A.;
Webber, D.N.;
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| 2024/81 | 15/11/2024 |
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
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AUTHOR:
Johnson, K.S.;
Jordan, L.K.;
McKenzie, J.R.;
Bian, R.;
Williams, J.R.;
Underwood, M.J.;
Morrison, M.A.;
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| 2024/80 | 15/11/2024 |
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
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AUTHOR:
Moore, B.R.;
Ó Maolagáin, C.;
Spong, K.;
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| 2024/79 | 15/11/2024 |
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.
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AUTHOR:
Beentjes, M.P.;
Miller, P.;
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| 347 | 15/11/2024 |
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
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AUTHOR:
Pinkerton, M.H.;
Halfter, S.;
Stewart, R.;
Robinson, K.V;
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| 2024/86 | 15/11/2024 |
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.
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ISBN:
978-1-991330-34-5;
ISSN:
1179-5352;
FAR:
FAR 2024/86;
AUTHOR:
Mormede, S.;
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| 2024/78 | 15/11/2024 |
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.
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AUTHOR:
Beentjes, M.P.;
Page, M.;
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| | 15/11/2024 |
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
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ISBN:
978-1-991330-33-8;
ISSN:
1179-5352;
FAR:
FAR 2024/85;
AUTHOR:
Mormede, S.;
S. Dunn, A;
Webber, D.;
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| 2024/77 | 05/11/2024 |
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).
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AUTHOR:
Stevens, D.W.;
Ballara, S.L.;
Maurice, A.;
Escobar-Flores, P.C.;
Yeoman, J.;
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| 346 | 30/10/2024 |
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.
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AUTHOR:
South, P.M.;
Delorme, N.J.;
Ragg, N.L.C.;
Taylor, D.I.;
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| 345 | 30/10/2024 |
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.
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AUTHOR:
Finucci, B.;
Dunn, M. R.;
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| 2024/72 | 25/10/2024 |
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
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AUTHOR:
Holmes, S.J.;
McGregor, V.L.;
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| 2024/76 | 25/10/2024 |
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.
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ISBN:
978-1-991330-14-7;
ISSN:
1179-5352;
FAR:
2024/76;
Author:
McGregor, V.L.;
Holmes, S.J.;
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| 2024/75 | 21/10/2024 |
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.
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AUTHOR:
Guccione D.G.;
Judd S.J;
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| 2024/74 | 21/10/2024 |
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.
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AUTHOR:
Ballara, S.L.;
Barnes, T.C.;
Hart, A.;
Sutton, C.;
Ó Maolagáin, C.;
Spong, K.;
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| 2024/73 | 21/10/2024 |
This report documents the age and length frequency data collected for southern blue whiting (SBW) in the 2023–24 fishing year from the Campbell Rise and Bounty Platform. These data add to the time series produced for the previous fishing years using the same methods. For Campbell Rise, a strong year class was observed which corresponded to SBW born in 2015. For Bounty Platform two strong year classes were observed, corresponding to SBW born in 2012 and 2018.
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AUTHOR:
Datta, S.;
Hart, A.;
Barnes, T.;
Sutton, C.;
Spong, K.;
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| 2024/71 | 18/10/2024 |
This report updates the catches, catch per unit effort, length-at-age and catch-at-age data for hoki in the 2022–23 fishing year. Data in this report were incorporated in the model for the hoki stock assessment in 2024.
The overall catch in the 2022–23 fishing year was higher than the catch in 2021–22. Catch increased in most areas but decreased in west coast South Island and Puysegur. The CPUE indices varied by area but were all at or above the long-term average.
Most of the catch in 2022–23 was of fish 45–90 cm in length from the 2006–20 year classes. The most recent (2020 and 2021) year classes appear to be lower than average.
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AUTHOR:
Ballara, S.L.;
Grüss, A.;
Escobar-Flores P.C.;
O’Driscoll, R.L.;
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| 2024/69 | 18/10/2024 |
Snapper is New Zealand’s most important commercial inshore fish species.
This describes a research study conducted in 2022–23 to find out the size and age of snapper from the commercial fishery in SNA 1 and the northern part of the SNA 2 stock, which covers most of the east coast of New Zealand North Island.
Snapper from four different fishing methods were sampled; bottom longline, bottom trawl, Danish seine and modular harvest system. In total, 47 873 snapper were measured and 5040 otolith pairs (fish ear stones) were collected for ageing by sampling 288 commercial fishing vessel catch landings at four fishing companies in SNA 1 and SNA 2, during October 2022 to August 2023.
The current study provides information that contributes to a 34 year time series. This series is used for assessments and fisheries management advice for snapper stocks.
The youngest average age of snapper was 7.4 years from the Bay of Plenty modular harvest system method and the oldest average age was 11.5 years from the Hauraki Gulf Danish seine method, the highest recorded average age in 34 years, indicating substantial improvement in the fishery. However, the average length of snapper was low, ranging from 30 cm to 36 cm, due to slower growth rates as the snapper population increases. SNA 2 north bottom trawl landings had a higher average size and weight for a given age (therefore faster growth) comp
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AUTHOR:
Walsh, C.;
Parsons, D.;
Bian, R.;
Armiger, H.;
Taylor, R.;
Evans, O.;
Madden, B.;
Bodie, C.;
Buckthought, D.;
Smith, M.;
Wood, B;
McKenzie, J;
Howarth, M.;
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| 2024/70 | 18/10/2024 |
The snapper fishery in Fisheries Management Area 2 (SNA 2) primarily occurs from Hawke Bay north to East Cape, on the east coast of the North Island. Snapper in this area are mainly taken as bycatch in trawling that targets tarakihi or gurnard.
As part of its management within the Quota Management System, snapper abundance in the north and south of SNA 2 is monitored using catch-per-unit-effort (CPUE) from bottom trawl fisheries and, in this report, this information is given for 2002 to 2023.
Snapper abundance in both the north and south of SNA 2 has increased between 2016 and 2023: by more than three times in the north and by almost eight times in the south. Snapper in the southern area was assessed as Very Likely (> 90%) to be at or above the target level in 2022–23.
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AUTHOR:
Middleton, D.A.J.;
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| 2024/68 | 18/10/2024 |
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.
Since at the late-1970s, the settlement rate of puerulus (early-life stage) red rock lobsters has been monitored at several sites around New Zealand. These data were once used by the stock assessments of some QMAs to inform annual recruitment (the appearance of young lobsters in the fishery), which was thought to help with making short-term predictions about future stock biomass. However, puerulus data have not been used by any of the most recent assessments for any QMA for different reasons.
This document describes a review of the puerulus monitoring data and their utility, along with climatic data, for predicting New Zealand red rock lobster recruitment.
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AUTHOR:
Roberts, J.O.;
Webber, D.N.;
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| 344 | 02/10/2024 |
This report presents the results of the updated trawl footprint in New Zealand waters within the Exclusive Economic Zone in waters open to trawling to a maximum depth of 1600 metres (fishable area).
Results are presented for the 1989–90 to 2021–22 fishing years for deepwater fisheries, and for the 2007–08 to 2021–22 fishing years for inshore fisheries, and combined inshore and deepwater (‘All stocks’) fisheries.
Statistics are presented on the measures of seabed contact for these groupings and include the area in square kilometres of the overall trawl footprints and aggregate (cumulative footprint) areas by year and all years combined. Other measures of contact also presented include the number of tows, the number of cells contacted (a 5 × 5 kilometre grid overlaid on the fishable area), and the number of ‘new’ cells contacted each year that had previously not been contacted.
This study also considered the above measures of contact when including midwater trawl used within five metres of the seabed and within ten metres of the sea bed. Methods were also developed to refine the placement of bottom-contacting trawl effort on underwater topographic features.
Results show that overall measures of contact have decreased in recent years for d
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AUTHOR:
MacGibbon, D.J.;
Mules, R.;
Goode, S.;
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| | 30/09/2024 |
Escobar-Flores, P.C.; O’Driscoll, R.L.; Ballara, S.L. (2024). Acoustic surveys of Cook Strait and east coast South Island hoki during winter 2023. New Zealand Fisheries Assessment Report 2024/67. 60 p.
Aggregations of spawning hoki were surveyed in Cook Strait and off the east coast South Island (ECSI), in Pegasus Canyon and Conway Trough. The surveys were carried out from 17 July to 30 August 2023 using NIWA’s research vessel Kaharoa.
A calibrated scientific echosounder was used to complete the surveys in each of the trips to the survey areas. Six acoustic surveys, or snapshots, of the main Cook Strait spawning grounds were completed between 17 July and 23 August 2023. Seven snapshots of Pegasus Canyon were completed from 30 July to 29 August and two of Conway Trough on 31 July – 1 August and 13 August 2023
An echosounder looking from 200 metres off the bottom up to the surface was deployed in the outer Pegasus Canyon as an experiment to study the movement of hoki in the area.
We found hoki schools in the main Cook Strait Canyon, in the deepwater southeast of the main Cook Strait Canyon, and in Pegasus Canyon, and Conway Trough.
The average abundance of hoki for Cook Strait in 2023 was 58 000 t. This was lower than the previous su
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ISSN:
1179-5352;
ISBN:
978-1-991308-94-8;
Author:
Escobar-Flores, P.C.;
O’Driscoll, R.L.;
Ballara, S.L.;
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| 2024/66 | 24/09/2024 |
New Zealand scallops (Pecten novaezelandiae) are a species of shellfish that live on the seabed in sandy coastal areas. Scallops support highly-valued commercial and non-commercial (customary and recreational) fisheries, but fishery closures have been put in place due to sustainability concerns.
In the Coromandel (SCA CS) scallop stock in northeastern New Zealand, the fishery was closed from 1 April 2022, except for within two defined areas in the Hauraki Gulf that remained open to scallop fishing, one at Te Hauturu-o-Toi/Little Barrier Island and one in the Colville Channel.
Scallop populations in these two areas were surveyed between June and August 2022 using a camera-based survey method. The method involved lowering a camera system into the sea from a boat and taking photographs of the seabed at different sites within the two areas. The photos were examined and scallops in the images were labelled, counted and measured.
The abundance of scallops was low compared to previous years. Few high-density scallop patches were observed. Based on these results, the Little Barrier and Colville Channel areas were closed to scallop fishing in December 2022.
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AUTHOR:
Williams, J.R.;
Hughes, R.;
Jordan, L.;
Middleton, C.J.;
Middleton, I.;
Underwood, M.J.;
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| 343 | 13/09/2024 |
Cyclone Gabrielle (13–14 February 2023) caused widespread severe damage in the Te Matau-a-Māui/Hawke’s Bay and Tairāwhiti/Gisborne regions. Soil erosion caused by intense rainfall deposited sediment and woody debris in river valleys and in the sea. This project measured the proportional contributions of major rivers to the cyclone sediment deposits in the sea, and describes the physical characteristics of these deposits.
River sources accounted for more than 98% of these mud-rich deposits. In northern Tairāwhiti, deposits were dominated by the Waiapu River. In Hawke’s Bay and Poverty Bay, cyclone sediment deposits mainly originated from the Mohaka and Wairoa-Nuhaka Rivers. These findings demonstrate that sediment plumes from Hawke’s Bay rivers were transported north along the coast, all the way around around Mahia Peninsula and deposited in Poverty Bay. The overwhelmingly land-derived origin of the marine deposits highlights the vulnerability of the East Coast to soil erosion and marine sedimentation.
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AUTHOR:
Swales, A.;
Haddadchi, A.;
Olsen, G.;
Orpin, A.;
Handley, S.;
Bind, J.;
Bilewitch, J.;
Hayden M.;
Yarnes C.;
Mountjoy, J.;
Bury, S;
Jung, R.;
Frontin-Rollet, G.;
Smith, L.;
Brooks, A.;
Davidson, S.;
Wilkinson, C.;
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| 2024/65 | 13/09/2024 |
Redbait is a small pelagic fish usually taken as a bycatch species in trawl fisheries around New Zealand. Some target fishing has occurred, mostly on the Chatham Rise, since the species was introduced to the Quota Management System in 2009.
Catches of redbait have varied substantially between years. In the largest fishery, in the Chatham Rise, east coast South Island, Southland and sub-Antarctic areas, catches have shown little trend over time. However, catches off the east and west coasts of the North Island and mid-upper South Island have reduced considerably since 2010.
To manage redbait within the Quota Management System, catch-per-unit-effort (CPUE)—using data from Fisheries New Zealand observers—is used to track redbait abundance. This suggests that abundance in the southern fishery peaked in 2002, and has also shown an increase during 2016–2022. Off the west coast, redbait abundance was estimated to have been high during 1999–2008, but much lower since 2010.
Stock dynamics of redbait in New Zealand remain unclear. It is possible that the southern fisheries have the youngest redbait
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AUTHOR:
Middleton, D.A.J.;
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