Preparation of data for protected species capture estimation, updated to 2017–18

Assessments of the capture of protected species in New Zealand commercial fisheries rely on observer and fisher-reported data. Fisheries observers document the captures of protected species, and these observer records are linked to fisher-reported effort data. The current report presents the preparation of observer-reported capture and effort data, and fisher-reported effort data, to the 2017–18 fishing year.

The preparation of the data for the 2017–18 fishing year largely followed the same procedures as in previous years. Some changes in the reporting of observed set-net effort followed changes in the way that these data were stored in the Centralised Observer Database (COD), and there were some changes made to the way that fisher-reported effort data in purse-seine fisheries were processed. The latter changes resulted in a decrease in the purse-seine effort in the Protected Species Captures (PSC) database.

A total of 799 observed captures that occurred during the 2017–18 fishing year were included in the PSC reporting tables. Of these captures, 656 were of birds, 111 were of seals or sea lions, 20 were of sharks or rays, eight were of cetaceans, and four were of turtles. A wide range of seabird species were caught in New Zealand fisheries. The most frequently observed caught seabird during the 2017–18 fishing year was white-chinned petrel, with 243 observed captures. Other seabird species with more than 50 observed captures during 2017–18 included white-capped albatross, sooty shearwater and southern Buller’s albatross; and there were more than ten observed captures of Salvin’s albatross, flesh-footed shearwater, black petrel and Westland petrel. Other captures of seabirds included three yellow-eyed penguin, and two captures of Fiordland crested penguin.

There were 103 observed New Zealand fur seal captures during 2017–18. There were eight observed New Zealand sea lion captures in trawl fisheries (three captures in squid trawl, two in scampi trawl, two in southern blue whiting trawl, and one in ling trawl). Observed cetacean captures during 2017–18 included four common dolphin caught in trawl fisheries, two pilot whale and two orca captures. Protected shark and ray captures reported by observers during 2017–18 included eleven spine-tailed devil ray, seven white pointer, one basking shark in squid trawl, and one oceanic whitetip shark. Turtle captures during 2017–18 included two leatherback turtle, one green turtle and one loggerhead turtle. The latter capture was the first record of a loggerhead turtle in New Zealand fisheries.

These data are available at on the PSC website (https://psc.dragonfly.co.nz/). This website allows the exploration of capture data by species, fishery, vessel length, area, and year. A full copy of the PSC database, and the associated code repository, has been provided to Fisheries New Zealand Research Data Management.