Tiny amounts can be serious for people with allergies

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.

The snapper biomass (core strata plus the 10–20 m strata) was the highest ever in the time series and nearly triple that from the previous survey in 2021, with most fish 20 years or younger. Juvenile snapper were caught mostly in the 10–20 m strata. These strata provide important information on future recruitment and contain a variable proportion of the adult population.

A catchability analysis of the survey indicates that the survey can be considered representative of the time series.

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 surveys, although, in 2023, the proportion of small males was less than in previous years.

Survey abundance (total blue cod mean catch rate) from the four surveys significantly increased between 2010 and 2014, with no change in 2018, followed by a significant decline of 57% in 2023.

The proportion of pots with no catch was similar for the first three surveys (25 to 32%), but in 2023 this increased to 49%. There were no trends in sex ratio over the time series which was around 50% male.

The age structure was similar among the four surveys with most fish between 4 and 8 years of age and relatively few fish over 10 years, particularly males. The fishing pressure is concentrated on just a few older cohorts, some of which are poorly represented.

Relative to the target reference fishing mortality of F=0.15 for blue cod, the estimated mortality in 2023 was nearly seven times higher, indicating that overfishing is occurring. Fishing mortality was also considerably higher than the target for all three previous surveys.

Rig nursery grounds were defined and ranked from a review of existing information and a nationwide set net survey of 14 major harbours and estuaries in 2011. Kaipara and Raglan harbours were very important nurseries, followed by Waitemata, Tamaki and Porirua harbours. South Island harbours do not appear to be important rig nurseries. Juvenile snapper and grey mullet were frequent bycatch in North Island estuaries, and were most abundant in the same harbours as rig.

This review of existing information describes the current state of knowledge on soft-sediment marine assemblages around New Zealand; it identifies hotspots of biodiversity; highlights threats to, and the vulnerability of, assemblages; discusses knowledge gaps; and recommends areas or assemblages that could be the subject of directed future research. The review is supported by The Marine Soft Sediment Biodiversity Bibliographic Database which houses over 700 references.

This report describes relationships, patterns and contrasts in benthic species composition, assemblages and habitats, both within and between sites and initial sampling strata across the Challenger Plateau and Chatham Rise. Data used came from four different fauna collection methods: DTIS video; seamount sled; still images taken along the DTIS video; and beam trawls.

The development and retrospective application of a system of trauma classification to all sea lions captured from 1999/00 to 2007/08 is discussed, and results compared across years and between groups (e.g. SLED versus non-SLED captures). A lack of brain examinations in the years before 2006/07, in combination with difficulties in interpreting lesions from frozen cadavers, means that this retrospective review has some limitations.

Rhodolith beds in New Zealand harboured high diversity of associated macroalgae and invertebrates, undescribed taxa as well new records and range extensions of known species. Subtidal beds were investigated, examining structure and physical characteristics at two locations in the Bay of Islands, and characterising two species, Lithothamnion crispatum and Sporolithon durum. Responses of these rhodolith species to environmental stressors were also investigated both in the field and in culture.

This document summarises the observational and research data for southern blue whiting to 2019. Included here are time series of relative abundance from the wide area R.V. Tangaroa acoustic surveys, as well as from local area aggregation industry vessel acoustic surveys, CPUE indices for Bounty Platform and Campbell Island Rise, and trawl survey indices for the Auckland Islands Shelf, Campbell Island Rise, and Pukaki Rise, as well as updated time series of length-at-age and catch-at-age.

This report presents a description of the distribution of the ling (Genypterus blacodes) trawl and longline fisheries on the west coast of the South Island (LIN 7WC), from 1989–90 up to the 2018–19 fishing year. Catch-per-unit-effort analyses of standardised for commercial line fisheries targeting ling and as bycatch in observed trawl fisheries on the west coast of the South Island (LIN 7WC) are also presented

This document summarises the observational and research data for southern blue whiting to 2018. Included here are time series of relative abundance from the wide area R.V. Tangaroa acoustic surveys, as well as from local area aggregation industry vessel acoustic surveys, CPUE indices for Bounty Platform and Campbell Island Rise, and trawl survey indices for the Auckland Islands Shelf, Campbell Island Rise, and Pukaki Rise, as well as updated time series of length-at-age and catch-at-age

This report presents available New Zealand commercial fishery catch-at-age data for hake (Merluccius australis) caught by trawl, and ling (Genypterus blacodes) caught by trawl and longline, up to the 2018–19 fishing year, and bottom trawl survey catch-at-age data sets for both species up to the summer of 2020.

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.