This study characterised the commercial surface-longline fisheries that capture striped marlin in New Zealand. It assessed operational and environmental factors impacting striped marlin bycatch rates. No clear trends in operational features increasing bycatch were detected, but spatial and seasonal patterns in the distribution of fishing effort appeared to explain a high proportion of captures by target species. Important environmental covariates were SST, chlorophyll-a, and moon illumination.

This report summarises bycatch and discards in hoki, hake, ling, silver warehou, and white warehou trawl fisheries for 1990–91 to 2016–17, based on analysis of fisheries observer and commercial catch effort data. Javelinfish, other rattails, and spiny dogfish were the main bycatch species recorded by observers. Total annual bycatch for the period ranged from 17 500 t to 49 000 t; total annual discards (for 2002–03 to 2016–17) were 5000 t to 25 000 t and decreased significantly after 2002–03.

This report reviews how year class strength parameters are described and estimated in age-based stock assessments within New Zealand and overseas. The report discusses a range of assumptions commonly made with respect to year class strength parameters, including whether it is dealt with in log-space versus natural space, the choice of prior, and whether to include a penalty and/or constraining parameters to have some mean value. Recommendations for further exploration are made.

This report updates the information on annual patterns of settlement for the red rock lobster (Jasus edwardsii) on crevice collectors at key sites. Settlement for the 2019 fishing year was notable for high settlement at Moeraki and low settlement at Gisborne, Napier, Kaikōura, Halfmoon Bay, and Jackson Bay. Castlepoint was just above to its long-term mean.

MPI Technical Paper no: 2021/12

Prepared for the Ministry for Primary Industries and the Ministry for the Environment by the Science Advisory Panel

This report reviews how year class strength parameters are described and estimated in age-based stock assessments within New Zealand and overseas. The report discusses a range of assumptions commonly made with respect to year class strength parameters, including whether it is dealt with in log-space versus natural space, the choice of prior, and whether to include a penalty and/or constraining parameters to have some mean value. Recommendations for further exploration are made.

This report describes research into the viability of self-completion modes of data gathering by amateur recreational marine fishers, with a view to estimating New Zealand's national annual harvest. The benchmark against which the alternatives are measured is the earlier National Panel Survey (NPS), which used computer assisted telephone interviews (CATI). Online self-complete substantially underestimates amateur harvest, and the app substantially overestimates harvest.

This report updates and summarises the observational and research data for southern blue whiting from 1990 to 2020. 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.

This leaflet provides an overview of sustainable indigenous forest management in New Zealand and gives landowners options for harvesting and milling timber from indigenous forests.