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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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2024/1204/03/2024
Title: FAR 2024/12 A 2020 preliminary stock assessment of ORH 7B
FAR-2024-12-2020-Preliminary-Stock-Assessment-ORH7B-4123.pdf (908.4 kb)
This report presents an assessment of the orange roughy stock off the west coast of the South Island (ORH 7B) in 2020. There was a fishery from 1985 to 1992, with the TACC peaking at 1708 t between 1989 and 1995, and the fishery was closed from October 2007. The assessment used two acoustic biomass estimates (2017, 2019) and a 2019 age frequency, completely rejecting the assumptions used in previous assessments that CPUE was directly proportional to biomass and that recruitment followed the assumed recruitment curve. This assessment is considered preliminary as work was stopped due to the conclusion that the acoustic surveys had probably missed a substantial proportion of the spawning biomass.
FAR: 2024/12;
ISSN: 1179-5352;
ISBN: 978-1-991120-96-0;
AUTHOR: Deepwater Group Ltd.;
2024/1004/03/2024
Title: FAR 2024/10 Rock lobster catch and effort data: 1979–80 to 2022–23
FAR-2024-10-Rock-Lobster-Catch-And-Effort-Data-197980-To-202223-4455.pdf (5.6 MB)
 This report summarises commercial catch and effort statistics for rock lobsters, which are also known in New Zealand as “crayfish” or “kōura”. 
 
The summaries presented in this document cover the rock lobster legal fishing years (1 April–31 March) for April 1979 to March 2023.
 
There are nine Quota Management Areas (QMAs) that cover all inshore waters of the North Island, the South Island, and the Chatham Islands. There are 43 smaller 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 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 2022–23 in this document. 
 
The sixth table for each QMA summarises catch-per-unit-effort (CPUE) by statistical area and fishing year. CPUE in this table is defined as the catch (in kilograms) from the second table div
FAR: 2024/10;
AUTHOR: Starr, P.J.;
ISSN: 1179-5352;
ISBN: 978-1-991120-94-6;
2024/1104/03/2024
Title: FAR 2024/11 A 2020 Stock Assessment Update of ORH 3B East and South Chatham Rise
FAR-2024-11-2020-Stock-Assessment-Update-ORH3B-East-And-South-Chatham-Rise-4122.pdf (974.2 kb)
This report provides a 2020 update of 2014 and 2017 assessments of the East and South Chatham Rise orange roughy stock, to enable an HCR-derived recommended catch limit for 2020–21. Three age-structured Bayesian population models were fitted to biomass and composition data. Virgin biomass (B0) was estimated as 300 000–350 000 t and 2020 stock status from the base case model was 36% B0 (± 95% CIs of 30 to 41%). With a vulnerable biomass of 157 000 t, the HCR-derived recommended catch limit was 6348 t for 2020–21, with a slowing increasing population over future years.
FAR: 2024/11;
ISSN: 1179-5352;
ISBN: 978-1-991120-95-3;
AUTHOR: Deepwater Group Ltd.;
2024/0916/02/2024
Title: FAR 2024/09 Estimation of finfish release survival from New Zealand inshore commercial fisheries
FAR-2024-09-Estimation-Of-Release-Survival-for-Inshore-Finfish-From-Commercial-Fisheries-4459.pdf (11.0 MB)
this study estimated the post-release survival of inshore finfish with current commercial minimum legal sizes—blue cod, blue moki, butterfish, kingfish, red moki, red cod, sand flounder, snapper, tarakihi, trevally, and yellowbelly flounder—and those currently allowed to be returned under disposal code X— kingfish, rig, sand flounder, school shark, rough skate, smooth skate, and spiny dogfish.
 
A questionnaire was developed and circulated to fishers, fishery observers, and scientists with knowledge of each species to obtain their estimates of at-release survival (i.e., the probability the fish/shark was alive when put back into water) and post-release survival (the probability an individual was both alive at release and survived following release). Estimates were obtained for each gear type as well as fishing categories within each gear type, e.g., duration, depth, and bag size. For some species, estimates of post- release survival were informed by literature on the survival of same or similar species.
 
These data were used with fishery characterisations to model the survival for each species. For species with a minimum legal size, both at-release and post-release survival estimates were used, whereas for those species released under disposal code X, which may only be released if alive and likely to survive, only the post-release survival estimates were used.
 
The
AUTHOR: McKenzie, J.R.; Underwood, M.J.; Jones, E.G.; Jordan, L.; Bian, R.;
FAR: 2024/09;
ISSN: 1179-5352;
ISBN: 978-1-991120-85-4;
2024/0815/02/2024
Title: FAR 2024/08 Commercial catch sampling for species proportion, sex, length, and age of jack mackerels in JMA 7 in the 2021–22 fishing year, with a summary of all available data sets.
FAR-2024-08-Commerical-Catch-Sampling-of-Jack-Mackerels-JMA7-To-202122-4431.pdf (4.0 MB)
Jack mackerels (JMA) 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 JMA 7. Three jack mackerel species are found in New Zealand waters, namely Trachurus declivis, T. murphyi, and T. novaezelandiae.
 
New Zealand commercial catches of jack mackerels have been recorded under the general 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 observer data which includes separate codes for each species, are essential for assessment of the individual stocks.
 
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 2021–22 fishing year, including estimates of species proportions and sex ratios in the landings, catch-at-length (fork length, cm), and catch-at-age for these species.
 
 
 
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 2021–22, proportions of T. declivis, T. novaezelandiae
FAR: 2024/08;
ISSN: 1179-5352;
ISBN: 978-1-991120-83-0;
AUTHOR: Moore, B.R; Ó Maolagáin, C.; Spong, K.; Barnes, T.;
 14/02/2024
Title: FAR 2024/07 Estimation of release survival of pelagic sharks and fish in New Zealand commercial fisheries
FAR-2024-07-Estimation-Of-Release-Survival-Of-Pelagic-Sharks-And-Fish-4445.pdf (9.7 MB)
 This project estimated survival of six pelagic species (southern bluefin tuna, Pacific bluefin tuna, swordfish, blue shark, mako shark, and porbeagle shark) following release from commercial fishing gear to inform a government review of their landing exceptions.
 
Fishery characterisations revealed that the main fishing gears responsible for discarded fish were surface longline (all species) and trawl (swordfish, mako, and porbeagle).
 
Literature reviews were conducted to document current knowledge on the status of an individual when brought to the vessel and ‘post-release’ survival (i.e., survival in the weeks to months following release) from these methods, as well as the factors that affect survival of each species. The key results were:
 
Bluefin tunas (including southern bluefin tuna and Pacific bluefin tuna) and swordfish typically have high post-release survival following capture by surface longline, with most studies reporting survival rates of 88% or greater for bluefin tunas and 50–88% for swordfish.
Blue shark have high at-vessel and post-release survival following capture by surface longline, with most studies reporting at-vessel and post-release survival rates of > 80%.
 
Mako have moderate to high at-vessel and post-release survival following capture by surface longline, with most studies reporting at-vessel and po
FAR: 2024/07;
ISSN: 1179-5352;
ISBN: 978-1-991120-82-3;
AUTHOR: Moore, B.R.; Finucci, B.;
2024/0513/02/2024
Title: FAR 2024/05 Review of photo calibration methods for scampi (Metanephrops challengeri) photo surveys
FAR-2024-05-Photo-Calibration-Methods-For-Scampi-Photo-Surveys-4428.pdf (4.8 MB)
 Photo surveys are used to estimate abundance of scampi in New Zealand and provide important information for stock assessments.
 
Readers identify features in the survey photos as burrows or scampi. A statistical model is applied to produce an estimate of abundance for each survey. The statistical model takes into account differences between readers’ interpretation of features (what looks like a burrow to one reader may not to another) and differences in interpreting features over time (e.g., a reader may become more skilled at interpreting features over time, or technology could improve).
 
This report provides a review of the statistical model applied to produce an estimate of abundance from scampi photo surveys. The review found no concerns with the model or how it is being applied. Two readers re-read images from recent survey years to test if the adjustment over time has been appropriate. The results of the re-reads supported the model results.
 
Further work is suggested, including contracting a specialist statistician to provide greater theoretical understanding of the model and assumptions.
AUTHOR: McGregor, V.L.; Holmes, S.J.; Underwood, M.J.;
 13/02/2024
Title: FAR 2024/06 Inshore trawl survey off the west coast South Island and in Tasman Bay and Golden Bay, March–April 2023 (KAH2302)
FAR-2024-06-Inshore-Trawl-survey-WCSI-And-Tasman-Bay-Golden-Bay-March-April-2023-KAH2302-4450.pdf (6.7 MB)
 This report presents the results from the 16th inshore trawl survey in a time series started in 1992 along the west coast of the South Island, from Farewell Spit to the Haast River mouth, and in Tasman Bay and Golden Bay.
 
The survey covers depths from 20 to 400 m (core strata) and surveys many species but is mainly focused on giant stargazer, red cod, red gurnard, spiny dogfish, and tarakihi. Since 2017, two additional strata have been surveyed in 10–20 m in Tasman Bay and Golden Bay to cover the full distribution of snapper in the geographic area.
 
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 2023, 58 phase one stations were successfully completed in the core strata and another six were carried out in strata 20 and 21. Four phase two stations were completed to reduce the coefficient of variation for spiny dogfish and snapper.
 
Biomass estimates (in tonnes) for the target species in the core strata were: giant stargazer, 915 t; red gurnard, 1498 t; red cod, 69 t; snapper, 3633 t; spiny dogfish, 3043 t; and tarakihi, 493 t.
 
FAR: 2024/06;
ISSN: 1179-5352;
ISBN: 978-1-991120-81-6;
AUTHOR: MacGibbon, D.J.; Walsh, C.; Buckthought, D. Bian, R.;
2024/0429/01/2024
Title: FAR 2024/04 Red rock lobster (Jasus edwardsii) settlement indices for the 2022–23 fishing year
FAR-2024-04-Settlement-Indices-For-Red-Rock-Lobster-For-202223-4451.pdf (2.7 MB)
 The rock lobster fishery is one of New Zealand’s most valuable fisheries.

Understanding larval settlement processes can greatly assist the management of this fishery because they may explain changes in recruitment to the fishery (i.e., reaching legal size), which takes between four and eleven years. This report aims to determine trends in puerulus settlement at selected key sites around New Zealand.

Annual patterns of red rock lobster settlement are described for North Island and South Island coastal areas, based on monthly monitoring of puerulus (the post-larval stage of red rock lobster) settlement collectors.

The monitoring data for 2022–23 are described in this report and used to provide indices of puerulus settlement for 2022–23, and thus extend the time series used to identify annual trends of settlement (since 1979).

Puerulus settlement during the 2022–23 fishing year was above the long-term mean at Gisborne, Castlepoint, and Halfmoon Bay and below the long-term mean at
AUTHOR: Forman, J.S.; McKenzie, A.; Stotter, D.R.;
2024/0326/01/2024
Title: FAR 2024/03 Relative abundance, size and age structure, and stock status of blue cod in Foveaux Strait in 2023
Relative abundance, size and age structure, and stock status of blue cod in Foveaux Strait in 2023.pdf (2.8 MB)
 South Island recreational blue cod fisheries are monitored by Fisheries New Zealand using potting surveys to assess the status of the stocks. The results of the Foveaux Strait surveys are important inputs for full quantitative stock assessments conducted for BCO 5 every five years.

This report describes the results of the random-site blue cod (Parapercis colias) potting survey carried out in Foveaux Strait in February 2023—as well as for three previous surveys (2010, 2014, and 2018). 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.

The overall weighted mean length of blue cod in 2023 was 32.0 cm for males and 28.5 cm for females, and mean age was 5.9 years (1–11 years) for males and 6.2 years for females (1–16 years). There were no clear age class modes in 2023 and little evidence of spawning activity during the survey.

The scaled length frequency distributions and mean length of all blue cod were similar for all four survey
FAR: 2024/03;
ISSN: 1179-5352;
ISBN: 978-1-991120-60-1;
AUTHOR: Beentjes, M.P.; Miller, A.;
2024/0225/01/2024
Title: FAR 2024/02 The 2023 stock assessment of ling (Genypterus blacodes) off the west coast South Island (LIN 7WC)
FAR-2024-02-2023-Ling-Stock-Assessment-Off-West-Coast-South-Island-LIN7WC-4423.pdf (4.0 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 2023 stock assessment of one of the five main ling stocks managed under the Quota Management System: the ling stock off the west coast of the South Island (LIN 7WC).
 
A stock assessment model was carried out, based on commercial catches, information from the west coast South Island Tangaroa trawl survey biomass series, the commercial longline standardised catch per unit effort (CPUE) from 1991, and the commercial trawl standardised CPUE from 1997. 
 
The initial spawning stock biomass (B0) for both the base case model was estimated to be about 62 200 t and stock status in 2023 was estimated as 51% B0. An investigative model run provided a slightly lower initial biomass and stock status in 2023 of 52%.
 
Five-year projections were done using the base case model, resampling recruitment from the entire range of the model, and assuming future annual catch equal to the average catch in 2020–2022. Projected stock status in 2028 was expected to be 52% of B0. 
 
The probability that the stock status in 2028 will be above 40% B0 was 97%, and that of being less than 20%, was zero. This assessment was used t
AUTHOR: Mormede, S.; Dunn, A.; Webber, D.N;
 16/01/2024
Title: FAR 2024/01 Catch-at-age for barracouta (Thyrsites atun) in BAR 5 and gemfish (Rexea solandri) in SKI 3and SKI 7 for the 2021–22 fishing year
FAR-2024-01-Catch-At-Age-For-Barracouta-BAR5-And-Gemfish-SKI3-And-SKI7-2022-4440.pdf (1.6 MB)
Catch-at-age data are important for the stock assessment of fish species because they provide information on the strength and progression of age classes in the stock, including juveniles and fish that are large enough to be taken by commercial fishers. These data include information on fish length and age (from otoliths—the ear bones of fish) collected at sea by observers from the commercial catch.
 
This report provides analyses 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 2021–22 fishing year. These results are the second of a three-year catch-at-age series for these two species.
 
Data for the 2021–22 season included few barracouta under 60 cm, indicating either less fishing on smaller (and younger) barracouta, or a poor year class should be expected. Most of the barracouta were aged 2–5 years.
 
Gemfish from SKI 3 in the 2021–22 fishing year showed a range of fish sizes, with most between 45 and 52 cm, which corresponded to age 2 fish, and also at sizes that corresponded to ages 4–6.
 
Gemfish from SKI 7 were less variable in length and included some fish under 50 cm, mainly females, which corresponded to ages 0–1. Most of the gemfish in SKI 7 around 50 cm in length co
FAR: 2024/01;
ISSN: 1179-5352;
ISBN: 978-1-991120-59-5;
AUTHOR: Devine, J.A.; Sutton, C.; Hart, A.;
2023/6413/12/2023
Title: FAR 2023/64 Stock survey of the Foveaux Strait oyster (Ostrea chilensis) fishery (OYU 5), population size structure, and Bonamia exitiosa prevalence, intensity, and disease mortality in February 2023
FAR-2023-64-Foveaux-Strait-Oyster-And-Bonamia-Survey-OYU5-February-2023-4417-combined.pdf (14.6 MB)
 A stock assessment survey of Foveaux Strait oysters (OYU 5) in February 2023 found numbers of commercial-sized, recruit, pre-recruit oysters, and small oysters had decreased by between 44.8% and 52.3% from 2022 numbers. Winter-spring disease mortality is the most likely cause. These decreases cannot be fully explained by fishery and survey data. Summer mortality from Bonamia increased from 5% in 2022 to 9% in 2023. Mostly large oysters died; 70% of oysters are below recruit-size. Spat settlement was high.
AUTHOR: Michael, K.P.; Forman, J.; Smith, L.; Brooks, A.R.; Moss, G.;
 11/12/2023
Title: AEBR 325 Novel technologies to mitigate the risk of dolphin capture in inshore trawl fisheries: field Implementation and data analysis
AEBR-325-Novel-Technologies-For-Inshore-Fisheries-Dolphin-Capture-Risk-Mitigation-4441-2023.pdf (7.8 MB)
 New Zealand’s Hector’s dolphins are an endangered species. A key threat to their survival is entanglement in fishing gear, including trawl nets. In this study, we report on a field trial where underwater microphones (hydrophones) were fitted to trawling equipment and the echolocation clicks naturally produced by Hector’s dolphins were localised to determine how the dolphins interacted with the trawling equipment as it moved through the water. The hydrophones were protected within custom-built cages to withstand the physical stress associated with being attached to fishing equipment that is dragged along the seabed. The field trial was conducted off the coast of Timaru, New Zealand, in September and October 2022. While the hydrophones recorded dolphin sound underwater, a Fisheries New Zealand observer on the boat also looked out for dolphins.
 
The protective cages around the hydrophones proved effective and we were able to successfully localise dolphins. Dolphins were localised moving towards the mouth of the fishing net from various approach angles, and, on several occasions, we were able to successfully distinguish multiple dolphins each moving along different paths. Even though we only analysed a subset of the acoustic data from each trawl, dolphin clicks were detected acoustically during trawls on more occasions than the observer on the fishing boat was able to see dolphins. Unfortunately silt from the seabed entered some of
AEBR: 325;
ISSN: 978-1-991120-52-6; 1179-6480;
AUTHOR: Warren, V.E.; Delarue, J.J.-Y.; McEachern, J.; Martin, S.B.; McPherson, C.R.;
 11/12/2023
Title: FAR 2023/63 Review and summary of the time series of input data available for the assessment of southern blue whiting (Micromesistius australis) stocks up to and including the 2022 season
FAR-2023-63-Southern-Blue-Whiting-Fisheries-Characterisation-Up-To-2022-4422.pdf (8.7 MB)
 This report updates and summarises the observational and research data for southern blue whiting from 1990 to 2022. These data include the time series of relative abundance from acoustic surveys, trawl survey indices, and updated time series of length-at-age and catch-at-age from observer sampling of commercial catch.
FAR: 2023/63;
ISSN: 1179-5352;
ISBN: 978-1-991120-41-0;
AUTHOR: Holmes, S.J.; Bian, R.; Doonan, I.J.;
32424/11/2023
Title: AEBR 324 Fishery-induced trophic cascades and sea urchin barrens in New Zealand: a review and discussion for management
AEBR-324-Fishery-Induced-Trophic-Cascades-And-Urchin-Barrens-Review-4426-2023.pdf (4.8 MB)
 Sea urchin barrens are sea urchin dominated areas of rocky reef that would normally support healthy kelp forest, but have little or no kelp due to overgrazing by sea urchins.
 
This review updates our understanding of sea urchin barrens in New Zealand and the role fishing plays in their establishment to date. It also identifies key work required to support management decisions, including collating data on the distribution of urchin barrens, reviewing information required to set catch limits for sea urchin predators, and developing regional management approaches.
 
We review published scientific literature on sea urchin barrens in New Zealand and the role of fishing in their development.
 
We also summarise results of a national workshop to support management of sea urchin barrens.
 
Research based on observations from marine protected areas suggests fishing of sea urchin predators is causing and/or maintaining sea urchin barrens in north-east New Zealand.
 
The extent of sea urchin barrens and contributing factors in other parts of New Zealand appear to vary, but there are few published studies on this. 
 
Workshop discussions indicated an urgent need to develop a suite of management options to address sea urchin barrens at regional scales in collaboration with tangata whenua and stakeholders.
AEBR: 324;
ISSN: 1179-6480;
ISBN: 978-1-991120-29-8;
AUTHOR: Doheny, B.; Davis, J.P.; Miller, B.;
2023/6117/11/2023
Title: FAR 2023/61 Stock assessment of trevally (Pseudocaranx georgianus) for TRE 1 to 2021/22
FAR-2023-61-Trevally-Stock-Assessment-TRE1-To-202122-4432.pdf (4.4 MB)
For the Bay of Plenty base model run current biomass was estimated to be 68.4% B0 (median), with 95% credible interval 46.6–97.7% B0. For all five-year projection scenarios, there was a low probability that the target biomass would decline below the target level of 40% B0. A stock assessment was also attempted for a Ninety Mile Beach/East Northland/Hauraki Gulf stock, but was unsuccessful due to conflicts between the abundance and catch-at-age data.
FAR: 2023/61;
ISSN: 1179-5352;
ISBN: 978-1-991120-25-0;
AUTHOR: McKenzie, A.;
32317/11/2023
Title: AEBR 323 Habitat use and the impact of multiple stressors on blue cod populations in Canterbury and the Marlborough Sounds
AEBR-323-Habitat-Use-And-Impact-Of-Stressors-On-Blue-Cod-4425-2023.pdf (4.5 MB)
 Changes in blue cod populations off Canterbury and in the Marlborough Sounds has raised concerns about the impact of human stressors on these populations, but the relationship between most stressors and blue cod is unknown.
 
Information on blue cod abundance was matched with environmental data to understand the habitat characteristics important for blue cod adults and juveniles off three Canterbury sites; Banks Peninsula, Motunau, Kaikōura.
 
Changes in potential stressors to blue cod habitat were compared with blue cod population status over 20 years at the sites off Canterbury and in the Marlborough Sounds.
 
Blue cod were associated with areas where the seafloor is rough and complex (e.g., reef systems), where structural habitat was provided by plants and animals, and in areas with higher water clarity and lower temperature.
 
Blue cod population status was related to stressors from land use (e.g., coastal water quality), and increasing water temperatures in most locations, although the intensity of these stressors has varied substantially over time and among locations.
 
This information provides guidance on the scale and focus for future research and potential management opportunities to limit these stressors and ensure sustainability of the blue cod fishery.
AEBR: 323;
ISSN: 1179-6480;
ISBN: 978-1-991120-23-6;
AUTHOR: Brough, T.E.; Leunissen, E.M.; Beentjes, M.;
2023/6217/11/2023
Title: FAR 2023/62 Pāua harvest estimates by land-based amateur fishers—Kaikōura Marine Area in 2023
FAR-2023-62-Paua-Harvest-Estimates-From-Land-Based-Amateur-Fishers-Kaikoura-2023-4438.pdf (2.7 MB)
This report describes the survey estimates for blackfoot pāua landed by amateur fishers from land-based access points in the Kaikōura Marine Area and Oaro during a two-month open season from 15 April 2023. This was the second survey conducted to estimate amateur harvest of pāua in the Kaikōura Marine Area and the first to provide cumulative harvest estimates weekly during the open season. Harvest numbers were estimated for rock lobster, yellowfoot pāua, and kina.
FAR: 2023/62;
ISSN: 1179-5352;
ISBN: 978-1-991120-26-7;
AUTHOR: Holdsworth, J.C.; Curtis, S.; Neubauer, P.;
2023/6017/11/2023
Title: FAR 2023/60 Biomass survey and condition index for kina (Evechinus chloroticus) in SUR 7A
FAR-2023-60-Kina-Biomass-Survey-And-Condition-Index-SUR7A-4433.pdf (1.2 MB)
This report presents the results of a field survey made in December 2022 to estimate the abundance of kina in Tory Channel, Marlborough Sounds (SUR 7A). Kina densities were determined along with roe biomass from dive and camera transects, with estimates of abundance utilising high resolution bathymetry data. Total biomass of kina in the survey area was estimated to be 595 t, with a CV of 19%; the biomass of kina roe was estimated to be 62.9 t, most of which was in the highest quality category.
FAR: 2023/60;
ISSN: 1179-5352;
ISBN: 978-1-991120-24-3;
AUTHOR: Anderson, O.F.; Olsen, L.; Marriott, P.; Stead, J.; Hayden, M.; Olmedo-Rojas, P.;
2023/5916/11/2023
Title: FAR 2023/59 Further development of models for arrow squid in New Zealand waters
FAR-2023-59-Further-Development-Of-Models-For-Arrow-Squid-4408.pdf (8.0 MB)
This report summarises population models for arrow squid in the Subantarctic. The models captured the main biological processes adequately. Recruitment estimates were robust to model assumptions and structure. However, absolute estimates of biomass were highly uncertain. The potential for in-season management was tested. Proxies that could be used to compare current relative exploitation rates with past conditions were also investigated; these could be used for hindcasting.
FAR: 2023/59;
ISSN: 1179-5352;
ISBN: 978-1-991120-22-9;
AUTHOR: Mormede, S.; Dunn, A.; Webber, D.N.;
2023/5815/11/2023
Title: FAR 2023/58 The 2022 stock assessment for scampi (Metanephrops challengeri) in the Bay of Plenty (SCI 1) and Hawke Bay-Wairarapa (SCI 2) 1990–2022
FAR-2023-58-Scampi-2022-Stock-Assessment-For-SCI1-And-SCI2-To-2022-4348.pdf (7.5 MB)
Fisheries stock assessments were undertaken for SCI 1 and SCI 2. The SCI 1 assessment was rejected by the Fisheries New Zealand Deepwater Working Group due to sensitivity to the trawl survey catchability prior. The SCI 2 assessment was accepted, but with a lower quality rating due to unresolved conflicts in data inputs. For SCI 2 current status in 2022 was estimated to be 56% B0 and likely within 47–66% B0. Projections were not carried out with either assessment.
 
FAR: 2023/58;
ISBN: 978-1-991120-21-2;
ISSN: 1179-5352;
AUTHOR: McGregor, V.L.;
2023/5714/11/2023
Title: FAR 2023/57 Climate impacts on fished populations. Part 2: Effects of climate and environmental variability on fishery stock assessment accuracy
FAR-2023-57-Climate-Impacts-On-Fished-Populations-Part2-Stock-Assessment-4178.pdf (9.5 MB)
 This study used a model of individual eco-physiological response to environmental and climate factors to derive population level outcomes of fish stocks. These simulations were used to investigate how fisheries stock assessments are influenced by climate and bottom-up variability in production parameters. The assessments generally provided unbiased estimates of stock status even though there were annual and decadal fluctuations in all production-related parameters.
AUTHOR: Neubauer, P. ; A’mar, T. ; Dunn, M.;
FAR: 2023/57;
ISSN: 1179-5352;
ISBN: 978-1-991120-15-1;
2023/5614/11/2023
Title: FAR 2023/56 Climate impacts on fished populations. Part 1: Simulating bottom-up, physiological, and fishery-induced changes in production potential
FAR-2023-56-Climate-Impacts-On-Fished-Populations-Part1-4177.pdf (5.1 MB)
This study assessed the influence of climate on fish stocks by developing a model of individual eco-physiological response to environmental factors. The model was used to derive population level outcomes, and to investigate the response of fish stocks to climate variation at different levels of fishing intensity. The findings suggest that productivity parameters need to be considered in combination with density-dependent responses to determine the impact of climate change on fish stocks.
AUTHOR: Neubauer, P. ; A’mar, T. ; Dunn, M.;
ISSN: 1179-5352;
ISBN: 978-1-991120-14-4;
FAR: 2023/56;
2023/5530/10/2023
Title: FAR 2023/55 A review of the Foveaux Strait oyster (OYU 5) stock assessment model and recommendations for future development
FAR-2023-55-Foveaux-Strait-Oyster-OYU5-Stock-Assessment-Review-And-Recommendations-4345.pdf (2.2 MB)
The Foveaux Strait oyster (OYU 5) stock assessment model was reviewed. Development of a disease sub-model to provide projections of future disease mortality will greatly improve assessments. B0 and stock reference points may be overestimated. Conceptual models of climatic, environmental, habitat, disease, and biological drivers of oyster production highlight several knowledge gaps. An understanding of disease processes and new time series data will underpin better stock projections.
FAR: 2023/55;
ISBN: 1179-5352;
ISSN: 978-1-991120-09-0;
AUTHOR: Michael, K.P.; Doonan, I.J.; Lane, H.S.; Datta, S.;
2023/5430/10/2023
Title: FAR 2023/54 Drivers of long-term change in the Foveaux Strait oyster (Ostrea chilensis) fishery (OYU 5)
FAR-2023-54-Drivers-Of-Long-Term-Change-Foveaux-Strait-Oysters-OYU5-4346.pdf (4.5 MB)
Drivers of long-term change in the Foveaux Strait oyster fishery (OYU 5) including the effects of disease and dredging essential oyster habitat are investigated. High densities of oysters are determined by recruitment and mortality from Bonamia exitiosa. Regular recruitment to the population shows productivity of the oyster fishery is high and is not likely to have changed. Oyster factors, co-infections with other pathogens, and climatic variables may affect oyster mortality and recruitment.
FAR: 2023/54;
ISSN: 1179-5352;
ISBN: 978-1-991120-08-3;
AUTHOR: Michael, K.P.;
2023/5317/10/2023
Title: FAR 2023/53 Stock assessment research in 2023 for silver warehou in SWA 3 and SWA 4
FAR-2023-53-Silver-Warehou-Stock-Assessment-Research-In-2023-SWA3-And-SWA4-4406.pdf (5.7 MB)
The silver warehou stock assessment conducted in 2023 is described. The assessment was ultimately rejected by the Fisheries New Zealand Deepwater Working Group. The data inputs and model assumptions are described. The main problems encountered, concerning stock structure, CPUE, age data, and model specifications, and their possible solutions, are discussed.
FAR: 2023/53;
ISBN: 978-1-991120-04-5;
ISSN: 1179-5352;
AUTHOR: Dunn, M.R.; McGregor, V.L.;
32216/10/2023
Title: AEBR 322 Desktop update of estimation of seabird cryptic mortality in trawls, via warp and net captures in the New Zealand domestic fleet using standard mitigation
AEBR-322-Desktop-Update-Estimation-Of-Seabird-Cryptic-Mortality-In-Domestic-Trawl-Fisheries-2023-4323.pdf (1.0 MB)
The study investigates cryptic mortality (i.e., deaths that are not observed) of seabirds in New Zealand’s trawl fisheries, separately for net captures and warp cable strikes. For net capture-related mortality, the results suggest that, on average, mortality was 2.5 times higher than when only based on observed captures. For warp strikes, estimates varied based on data sources, highlighting the need for tailored data collection due to uncertainties and sparseness in the current dataset.
AEBR: 322;
ISSN: 1179-6480;
ISBN: 978-1-991120-02-1;
AUTHOR: Meyer, S.;
32113/10/2023
Title: AEBR 321 Updated fisheries risk assessment framework for seabirds in the Southern Hemisphere
AEBR-321-Updated-Risk-Assessment-Framework-For-Southern-Hemisphere-Seabirds-2023-4407.pdf (6.1 MB)
The Spatially Explicit Fisheries Risk Assessment framework has recently been updated and applied to assess the fisheries risk to seabird populations within the New Zealand EEZ. In the current report, the approach is applied to seabirds globally in the southern hemisphere. Catchabilities were estimated from New Zealand captures. Then global fishing effort and species distributions were collated and used to assess the risk to seabirds from predicted fisheries captures throughout their range.
AEBR: 321;
ISSN: 1179-6480;
ISBN: 978-1-991087-93-5;
AUTHOR: Edwards, C.T.T.; Peatman, T.; Roberts, J.O.; Devine, J.A.; Hoyle, S.D.;
2023/5210/10/2023
Title: FAR 2023/52 Recruitment of freshwater eels, 1995–2022
FAR-2023-52-Recruitment-Of-Freshwater-Eels-1995-To-2022-4434.pdf (9.3 MB)
Data on elver catches of longfin and shortfin eels from hydroelectric barriers were collected during the 2018–19 to 2021–22 seasons. Catches contained moderate shortfin numbers, but moderate-high longfin numbers. Combined recruitment indices from all sites and seasons showed that recruitment of both species is variable within and between sites but remained stable, consistent with previous studies, indicating that recruitment of elvers has remained stable within the time frames of the datasets.
FAR: 2023/52;
ISSN: 1179-5352;
ISBN: 978-1-991087-98-0;
AUTHOR: Crow, S.K.; Lambert, P.W.; Egan, E.M.; Bowman, E.;
2023/5110/10/2023
Title: FAR 2023/51 Descriptive analysis of ling off the west coast South Island (LIN 7WC) up to 2021–22 and inputs for the 2023 stock assessment
FAR-2023-51-Descriptive-Analysis-Of-Ling-In-LIN7WC-To-202122-And-2023-Assessment-Inputs-4403.pdf (19.7 MB)
This report summarises the ling stock off the west coast South Island (LIN 7WC) and fishery. It describes the spatial structure of the stock, biological parameters, and trawl and longline standardised catch per unit effort (CPUE). Statistical Area 032 was reassigned to LIN 7WC based on the continuity of catch locations. The trawl and longline fishery CPUE and survey biomass showed similar patterns from 2000, with a decline from 2012. All three indices were considered in the stock assessment.
FAR: 2023/51;
ISBN: 978-1-991087-97-3;
ISSN: 1179-5352;
AUTHOR: Mormede, S.; Dunn, A.; Webber, D.N.;
2023/5010/10/2023
Title: FAR 2023/50 Towards an assessment of arrow squid in New Zealand waters
FAR-2023-50-Towards-An-Assessment-Of-Arrow-Squid-In-New-Zealand-Waters-4391.pdf (12.5 MB)
This report investigated the spatial and temporal structure of arrow squid (Nototodarus sloanii and N. gouldi) in New Zealand. Five potential stocks were defined. Estimates of growth rate were consistent with previous estimates. Spatial-temporal standardised CPUE fortnightly indices were developed and could be predicted relatively well by environmental variables. Preliminary population models showed recruitment was well estimated but initial biomass was highly uncertain.
FAR: 2023/50;
ISSN: 1179-5352;
ISBN: 978-1-991087-95-9;
AUTHOR: Mormede, S.; Dunn, A.;
2023/4909/10/2023
Title: FAR 2023/49 The 2023 Management Strategy Evaluation for hoki (Macruronus novaezelandiae)
FAR-2023-49-The-2023-Management-Strategy-Evaluation-For-Hoki-4396.pdf (2.7 MB)
A Management Strategy Evaluation (MSE) was conducted for hoki based on the recent (2022) stock assessment model. The MSE evaluated a set of Harvest Control Rules that specified a target biomass range and varied annual fishery catches relative to fluctuations in eastern and western stock biomass.
FAR: 2023/49;
ISSN: 1179-5352;
ISBN: 978-1-991087-94-2;
AUTHOR: Langley, A.D.;
2023/4819/09/2023
Title: FAR 2023/48 The 2022 stock assessment of hake (Merluccius australis) off the west coast South Island (HAK 7)
FAR-2023-48-The-2022-Hake-Stock-Assessment-HAK7-4389.pdf (12.1 MB)
 This report summarises the stock assessment of hake off the west coast South Island (WCSI) in HAK 7 for the 2021–22 fishing year. The index of abundance was the WCSI trawl survey. Initial spawning stock biomass was estimated as 78 870 t (95% CIs 74 140–84 810) with current status of 39% B0 (95% CIs 30–52% B0). Five-year projections showed that biomass would increase under average recruitment but would remain flat if future recruitments were low and catches were the same as the TACC.
AUTHOR: Dunn, A.; Mormede, S.; Webber, D.N;
FAR: 2023/48;
ISSN: 1179-5352;
ISBN: 978-1-991087-87-4;
2023/4419/09/2023
Title: FAR 2023/44 Descriptive analysis and model inputs for the 2022 stock assessment of hake (Merluccius australis) off the west coast South Island (HAK 7), to the 2020–21 fishing year
FAR-2023-44-Descriptive-Analysis-And-CPUE-For-Hake-HAK7-To-2020-01-4388.pdf (14.7 MB)
 This report summarises the WCSI hake (HAK 7) fishery with spatial structure of the stock, biological parameters, and standardised catch per unit effort (CPUE). The CPUE indices were similar for the tow-by-tow data and the daily summary data and showed a similar trend to the Sub-Antarctic trawl surveys. In general, the CPUE indices had declined over the period of fishing but had levelled off in recent years as the total catch declined.
AUTHOR: Dunn, A.; Mormede, S.; Webber, D.N.;
FAR: 202/44;
ISSN: 1179-5352;
ISBN: 978-1-991087-49-2;
2023/4704/09/2023
Title: FAR 2023/47 2022–23 International Spatial Modelling Workshop Programme: NIWA Yellowfin tuna simulation study.
FAR-2023-47-International-Spatial-Modelling-Workshop-Programme-NIWA-Yellowfin-Tuna-Simulation-4325.pdf (11.1 MB)
This report presents the NIWA analysis of simulated Indian Ocean Yellowfin tuna (IOYT) data as part of the 2022–23 International Approaches and Advancements in Spatial Stock Assessment workshop programme. Two stock assessment model structures were developed and evaluated and are the focus of this report: a single area model which used the aggregated datasets, and a fleets-as-areas model.
FAR: 2023/47;
ISSN: 1179-5352;
ISBN: 978-1-991087-79-9;
AUTHOR: Marsh, C.; A’mar, T.; McKenzie, J.; Hoyle, S.;
2023/4601/09/2023
Title: FAR 2023/46 The 2023 stock assessment and management procedure evaluation for pāua (Haliotis iris) fisheries in PAU 5D
FAR-2023-46-2023-Paua-PAU5D-Stock-Assessment-And-Management-Procedure-Evaluation-4401.pdf (4.7 MB)
The present project provides an update to the pāua (Haliotis iris) stock assessment for quota management area (QMA) PAU 5D and tested control rules to aimed at rebuilding catch towards the Total Allowable Commercial Catch. The findings suggested that the stock has been rebuilding and is now as likely as not to be at the interim management target. The harvest control rule from 2016 was updated to include a lag year on increases and a maximum 5% limit on year-on-year increases.
FAR: 2023/46;
ISSN: 1179-5352;
ISBN: 978-1-991087-75-1;
AUTHOR: Neubauer, P.; Kim, K.;
2023/4530/08/2023
Title: FAR 2023/45 Acoustic Biomass Surveys of Orange Roughy in ORH 3B North Chatham Rise, June/July, 2021
FAR-2023-45-Acoustic-Orange-Roughy-Surveys-ORH3B-June-July-2021-4301.pdf (15.2 MB)
 Acoustic biomass surveys of orange roughy (Hoplostethus atlanticus) in ORH 3B North Chatham Rise spawning grounds, 4–8 July 2021, on FV Amaltal Apollo. Surveys were undertaken on Morgue and Graveyard hills in NWCR and on the Rekohu aggregation in ESCR. The survey was prematurely curtailed due to vessel engine failure. Ancillary biomass estimates for Rekohu and Spawn Plume aggregations were derived from hull-mounted echosounder snapshots undertaken by FV Amaltal Mariner and FV San Waitaki. 
AUTHOR: Ryan, T.E.; Tilney, R.; Downie, R.;
FAR: 2023/45;
ISSN: 1179-5352;
ISBN: 978-1-991087-72-0;
32021/08/2023
Title: AEBR 320 Population size estimate of New Zealand sea lion (Phocarctos hookeri) for 2022
AEBR-320-New-Zealand-Sea-Lion-Population-Estimate-For-2022-2023-4420.pdf (6.3 MB)
 The total species population size estimate of New Zealand sea lion/pakake/whakahao was updated using the available demographic and population size information up to 2022 (the 2021–22 breeding season). All analyses were conducted within a Bayesian estimation framework, and the posterior total population size estimate was approximately 10 000 individuals in 2022 (median: 10 151; 95% credible interval: 8702–12 082 individuals), slightly below the estimate for 2015 using the same method.
AUTHOR: Roberts, J.; Edwards, C.T.T.;
AEBR: 320;
ISSN: 1179-6480;
ISBN: 978-1-991087-66-9;
31911/08/2023
Title: AEBR 319 Development of spatial fisheries risk assessment methods for sharks and turtles in New Zealand waters
AEBR-319-Spatial-Fisheries-Risk-Assessment-Method-Development-For-Sharks-and-Turtles-4405-2023.pdf (18.0 MB)
 A novel spatial risk assessment framework is proposed, based on the Spatially Explicit Fisheries Risk Assessment (SEFRA) and the Sustainability Assessment for Fishing Effects (SAFE). Risk is the probability that exploitation exceeds the Impact Sustainability Threshold (IST). Exploitation is estimated from the catchability and effort, using prior information on either the catchability or the population size. It is applied to shark and turtle species with different data characteristics.
AEBR: 319;
ISSN: 1179-6480;
ISBN: 978-1-991087-44-7;
AUTHOR: Edwards, C.T.T.;
2023/4310/08/2023
Title: FAR 2023/43 The 2022 stock assessment of red rock lobsters (Jasus edwardsii) in CRA 2
FAR-2023-43-The-2022-Stock-Assessment-For-CRA2-Red-Rock-Lobster-4395.pdf (21.6 MB)
This report documents the 2022 stock assessment of red rock lobsters in CRA 2. The model was fitted to length frequency data, sex ratio data, tag-recapture growth increment data, and standardised catch-per-unit-effort indices using the lobster stock dynamics model. This stock assessment estimated generally increasing exploitation rates throughout the stock’s history. Catch cuts and a period of improved recruitment have helped the stock rebuild since the 2017 stock assessment. 
FAR: 2023/43;
AUTHOR: Rudd, M.B.; Pons, M.; Webber, D.N.; Starr, P.J.; Roberts, J.; Goeden Z.D.;
ISSN: 1179-5352;
ISBN: 978-1-991087-48-5;
2023/4210/08/2023
Title: FAR 2023/42 Data for the 2022 stock assessment of red rock lobs
FAR-2023-42-Data-for-2022-Stock-Assessment-For-CRA2-Red-Rock-Lobster-4390.pdf (19.5 MB)
 This report documents the data used by the 2022 stock assessment of red rock lobsters in CRA 2. The data sets described include: catch estimates from commercial, recreational, customary, and illegal components of the fishery; standardised catch-per-unit-effort indices; standardised catch length-frequency distributions and sex ratios; tag-based growth information; and the proportion of mature females that were in berry (egg-bearing).
FAR: 2023/42;
AUTHOR: Roberts, J.; Webber, D.N.; Starr, P.J.; Rudd, M.B.; Pons, M.; Goeden, Z.;
ISSN: 1179-5352;
ISBN: 978-1-991087-47-8;
2023/4110/08/2023
Title: FAR 2023/41 Bottom trawl Catch-Per-UnitEffort indices for snapper in the Hauraki Gulf and east Northland (SNA 1), to 2020/21
FAR-2023-41-Snapper-CPUE-For-Hauraki-Gulf-And-East-Northland-Trawl-Fisheries-To-202021-4414.pdf (8.9 MB)
A spatial analysis of catch and effort data from the SNA 1 bottom trawl fishery was used to refine the boundary of the East Northland and Hauraki Gulf snapper stocks. For the two stock units, bottom trawl CPUE indices were derived for the spring-summer period. The two sets of CPUE indices were included in the 2023 stock assessment of SNA 1. 
FAR: 2023/41;
ISSN: 1179-5352;
ISBN: 978-1-991087-46-1;
AUTHOR: Langley, A.D.;
2023/4010/08/2023
Title: FAR 2023/40 Assessment of hoki (Macruronus novaezelandiae) in 2022
FAR-2023-40-Hoki-2022-Stock-Assessment-4349.pdf (23.2 MB)
 A fully integrated stock assessment is presented for HOK 1 modelled with two stocks (western and eastern) and with fish residing in four regions. The western stock is estimated to be lower than the eastern stock, with biomass expected to be 25–43% B0 in 2027 under current catch levels for the western stock and 46–55% B0 for the eastern stock. A simpler model with one stock and one region estimated current biomass to be 37–45% B0 in 2022. Target range for hoki is 35–50% B0.
FAR: 2023/40;
AUTHOR: McGregor, V.L.; Dunn, M.R.; Langley, A.D.; Dunn, A.;
ISSN: 1179-5352;
ISBN: 978-1-991087-43-0;
2023/3910/08/2023
Title: FAR 2023/39 Characterisation and CPUE analysis for scampi (Metanephrops challengeri) in the Bay of Plenty (SCI 1) and Hawke Bay-Wairarapa (SCI 2), 1990–2022
FAR-2023-39-Scampi-Characterisation-And-CPUE-For-SCI1-And-SCI2-1990-To-2022-4347.pdf (9.2 MB)
 Characterisation and CPUE (catch-per-unit-effort) analysis for SCI 1 (Bay of Plenty) and SCI 2 (Hawke Bay-Wairarapa) scampi (Metanephrops challengeri). Scampi live in burrows and variability in emergence rates impact the relationship between CPUE and abundance. SCI 1 index increased from 2016 to 2021. SCI 2 CPUE generally declined from 2015 to 2021. The CPUE indices were accepted by the New Zealand Fisheries Deepwater Working Group as valid for tracking scampi biomass for use in the stock assessment.
FAR: 2023/39;
AUTHOR: McGregor, V.L.;
ISSN: 1179-5352;
ISBN: 978-1-991087-42-3;
2023/3809/08/2023
Title: FAR 2023/38 Updated harvest control rule for SBW 6B to allow for years with no acoustic surveys
FAR-2023-38-Southern-Blue-Whiting-Updated-Harvest-Control-Rule-SBW6B-4355.pdf (530.8 kb)
 For southern blue whiting on the Bounty Plateau (SBW 6B), a new Harvest Control Rule, HCR2022, was developed that allowed for consecutive years with no acoustic surveys. HCR2022 replaced the previous HCR which required an acoustic survey every year.
FAR: 2023/38;
ISSN: 1179-5352;
ISBN: 978-1-991087-40-9;
AUTHOR: Doonan, I.J.;
2023/3709/08/2023
Title: FAR 2023/37 Acoustic estimates of southern blue whiting from the Campbell Island Rise, August-September 2022 (TAN2210)
FAR-2023-37-Southern-Blue-Whiting-Acoustic-Estimates-SWB6I-Aug-Sep-2022-TAN2210-4385.pdf (9.2 MB)
 The 14th acoustic survey of the southern blue whiting stock (SBW) off Campbell Island (SBW 6I) was carried out onboard RV Tangaroa between 28 August and 23 September 2022. Thirteen (snapshot 1) and ten (snapshot 2) strata were surveyed and twelve research mark identification trawls were completed during the survey. Estimates of biomass of adult SBW were slightly higher than the equivalent estimate from 2019. The average estimate of biomass of juvenile SBW was the highest in the time series.
FAR: 2023/37;
AUTHOR: Escobar-Flores, P.C.; Ladroit, Y.; Holmes, S.;
ISSN: 1179-5352;
ISBN: 978-1-991087-39-3;
31826/07/2023
Title: AEBR 318 Comparing results of black petrel capture interactions with bottom longlines using different data collection methods
AEBR-318-Data-Collection-Methods-Re-Black-Petrel-Capture-Interactions-With-Longlines-4351-2023.pdf (2.4 MB)
The impact of video monitoring on estimating black petrel bycatch in bottom longline fisheries was assessed. Combining observer and video monitoring data resulted in lower estimated captures compared with using observer data alone. Simulations of different proportions of assessed video footage suggest currently overpredicted estimates of black petrel captures. Also, the analysis suggests that the presence of observers and/or cameras increased fishers’ compliance to report black petrel captures.
AEBR: 318;
ISSN: 1179-6480;
ISBN: 978-1-991087-33-1;
AUTHOR: Meyer, S.; Hickcox R.;
31726/07/2023
Title: AEBR 317 Candidate species selection for the development of environmental health measures for open ocean salmon aquaculture
AEBR-317-Species-Selection-For-Open-Ocean-Aquaculture-Environmental-Health-Measures-4366-2023.pdf (1.6 MB)
While effects of organic enrichment on inshore, soft-sediment communities are well studied, little is known about how finfish farm-derived impacts will manifest in open ocean environments. This report identifies key species that may be affected by open ocean aquaculture and describes physiological indicators that may provide insight into organism health. This is the first of several project objectives that work toward developing environmental health measures for use in offshore environments.
AEBR: 317;
ISSN: 1179-6480;
ISBN: 978-1-991087-23-2;
AUTHOR: McMullin, R.M.; McGrath, E.C.;
2023/3617/07/2023
Title: FAR 2023/36 Relative abundance, size and age structure, and stock status of blue cod off south Otago in 2022
FAR-2023-36-South-Otago-Blue-Cod-Survey-In-2022-4402.pdf (3.4 MB)
This report describes the results of the random-site potting survey for blue cod (Parapercis colias) off south Otago in March–April 2022. Estimates are provided for population abundance, size and age structure, sex ratio, total mortality (Z), and fishing mortality (F). The 2022 potting survey was the fourth in the south Otago time series, with previous surveys in 2010, 2013, and 2018. The 2010 survey was a dual random-site and fixed-site experimental survey in three of the six strata; and 2013 and 2018 were solely random-site surveys in all six strata.
FAR: 2023/36;
ISSN: 1179-5352;
ISBN: 978-1-991087-27-0;
AUTHOR: Beentjes, M.P.; Fenwick, M.;
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