Using GPS tracking data obtained from yellow-eyed penguins since 2003, habitat models using the maximum entropy method were developed. Main factors determining habitat use were bathymetry, seafloor sediment composition, and colony distance. Acceptable model outputs were generated for North Otago and the Otago Peninsula as well as northern Stewart Island and Codfish Island. No adequate data were available for the Catlins, the eastern Foveaux Strait region, and southern Stewart Island; extrapolation from other regions proved unreliable. Habitat use maps are presented.
A survey of high-density breeding colonies of Westland petrels Procellaria westlandica, an endemic New Zealand seabird, undertaken between 2007 to 2011, conservatively estimated the population size to be 2827 (95%CI, 2143–3510) annual breeding pairs. The population may have been underestimated by up to 10% but is unlikely to have exceeded 4000 annual breeding pairs at the time of this survey. This estimate is the first detailed population estimate for all known breeding areas of this species.
Commercial catch-effort data and fisheries observer records of catch and discards by species were used to estimate the rate and level of non-target catch and discards in the ling longline fisheries for the fishing years 2002–03 to 2017–18. Estimates were made for broad categories of catch and discards including target species, QMS species, non-QMS fish, and non-QMS invertebrate species, and estimates of annual catch were made for several of the major individual non-target species.
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.
We used a new dataset of benthic invertebrate occurrence developed from quantitative seabed photographic surveys to build improved predictive models of taxon and community distributions on Chatham Rise. These predictions are the first abundance-based models of benthic distributions in the region and are the best-informed representations of seabed distributions on Chatham Rise to date, providing a resource that will have applications in marine environmental management and ecosystem research.
The present report details the preparation of data for the estimation of protected species captures in New Zealand commercial fisheries, including data from 2002–03 to 2017–18. Protected species captures included seabirds, marine mammals and turtles. The data preparation included the linking of observer records and fisher-reported data and updates, including changes to the fisher-reported purse-seine effort data, resulting in a decrease in the latter compared with the previous data preparation.
This report documents the preparation of data for the estimation of protected species captures in New Zealand commercial fisheries, up to the end of the 2016–17 fishing year. Recorded captures included captures of seabirds, marine mammals and turtles. The report describes the rationale for and impact of changes that were made to the processing of these data, when compared with the processing carried out in previous years.