This report presents analyses of the potential impacts of climate change on selected New Zealand finish. Historical research vessel catch data, likelihood clustering, and New Zealand Earth Systems Model hindcasts and forecasts, were used to estimate future redistribution of fish assemblages. A simulation model was used to examine the possible influence of climate change on stationary stock productivity.

This review assesses the feasibility of a deepwater shark tagging programme in New Zealand waters. Firstly, it provides a general overview of current knowledge on deepwater shark age and growth, movement and habitat use, and post-release survival. Secondly, the report discusses tagging study designs and application. Lastly, an assessment gives options for a deepwater shark tagging programme in New Zealand.

This study developed a method to assess risk to benthic habitats from fishing, using holothurians on the Chatham Rise as a case study. A spatial population distribution layer was developed. This layer and the bottom-contacting trawl footprint were then used in a Bayesian spatial population model to calculate the biomass trajectory and spatially and temporally explicit impact overlap statistics for the taxon. Species susceptibility was either assumed or estimated within the population model.

Vector Autoregressive Spatio-Temporal (VAST) models were applied to research trawl survey and environmental data to provide updated information on stock status for seven deepwater sharks. Deepwater sharks were found to be ubiquitous around New Zealand, with each species shown to have a unique distributional pattern. Deepwater shark “hotspots” in New Zealand waters were identified (e.g., Puysegur). There was little evidence to suggest any temporal or spatial changes in distribution or abundance.

This report describes bycatch of non-protected invertebrates from commercial fisheries and research trawls. Over 660 distinct taxa were identified which contribute to the ongoing discovery and taxonomic description of the New Zealand biodiversity. Specimen records and distribution points inform fisheries interactions with non-target benthic invertebrate bycatch and contribute to research on spatial planning and development of ecological risk assessments of fishing impacts on benthic habitats.

To examine the loss of seabirds (cryptic mortality) during a typical pelagic longline fishing trip, seabird ‘surrogates’ were manually attached to longline hooks under controlled conditions during a typical pelagic longline fishing operation. A single bird was attached to each hook in one of three ways. Almost all the surrogates were retained on retrieval of the gear. This study provides information that will permit refinement of scalars for cryptic mortality associated with pelagic longlines.

This study, conducted in stages over four years, synthesises available information on CO2 and climate-induced changes that affect the New Zealand region and our fisheries. The report reviews the known implications of these changes to the physical and oceanographic system in the coming decades, the state-of-knowledge of how specific fisheries may be affected and, where known, combines this information to determine potential risks to these fisheries.

This feasibility assessment considers passive acoustic monitoring systems, using the echolocation and communication clicks of the Hector’s dolphins to estimate their location within the water column, and therefore the proximity to demersal trawl fishing equipment. The study examines different array and localisation tracking concepts, possible detection ranges, and installation locations for hydrophones using theoretical simulations

The 2016 Kaikōura earthquake caused extensive uplift along the north-eastern coastline of the South Island of New Zealand. The disturbance resulted in damage to rocky reefs and widespread mortality of marine organisms, including important taonga and habitat-forming species such as pāua and bull kelp. This report describes the results of nearshore surveys at long-term monitoring sites between 2.5 and 3.5 years after the earthquake to assess the trajectories of recovery of rocky reef communities

This report presents an updated assessment of the risk of commercial fisheries in New Zealand for 71 seabird taxa breeding in this region, including data to the 2016–17 fishing year. The risk for seabirds was estimated as the ratio of total fishery-related deaths to the Population Sustainability Threshold, with 18 species having an estimated risk ratio that was non-negligible. Black petrel continued to be identified as the species most at risk from commercial fisheries in New Zealand waters.

The deepwater Tier 1 and Tier 2 target fishstock footprint for fishing years 2008–17 was estimated at 180 100 km2. This 10-year footprint contacted 4.4% of the Territorial Sea and EEZ seafloor area and 13% of the seafloor open to fishing, down to 1600 m. Tier 1 fisheries accounted for 87%, with hoki effort contributing 42%. The 2017 footprint covered 48 203 km2, lower than the 10-year median of 49 845 km2. The aggregated swept area from all bottom-contacting trawls for 2017 was 94 500 km2.

A SEFRA model was developed for female New Zealand sea lions at the Auckland Islands. Inputs to the model included: the estimated at-sea spatial density of female sea lions, and cryptic mortality priors relating to SLED use. Across the last 3 years assessed, the estimated annual risk ratio across all Auckland Islands fisheries was 0.24 (95% credible interval (CI) = 0.11–0.47); consistent with population recovery to 97.5% of unimpacted status when assuming deaths at the upper 95% CI level.

A dynamic Bayesian modelling framework (including user interface) was developed for the assessment of unobservable mortality (e.g. due to carcass loss during net retrieval) of New Zealand sea lions that interact with trawls using sea lion exclusion devices. A base case model suggested that the total fishery-related deaths are underestimated by a factor of 1.15 (95% credible interval: 1.05-1.31) and 1.60 (95% credible interval: 1.20-2.63) for bottom trawls and mid-water trawls, respectively.