Identification of marine mammals captured in NZ fisheries 2021/22

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INT2020-02: Identification of marine mammals captured in New Zealand fisheries (1 July 2021 to 30 June 2022) (PDF, 900K)

Summary

This project forms part of a wider Conservation Services Programme (CSP) research project that also covers the identification of turtles and protected fish species caught as bycatch and is designed to complement the existing seabird identification project.

The accurate determination of the taxon of marine mammals captured in New Zealand fisheries is vital for examining the potential threats to population viability posed by incidental fisheries captures. Observers on commercial vessels are not always able to identify marine mammals with high precision, and the assessment of the age class may require expert knowledge. Information gained through this project will link to FNZ databases and will inform ongoing capture estimations, risk assessments, research and modelling of the effects of fisheries incidental bycatch on various marine mammal species.

There were 115 marine mammal bycatch events reported between 1 July 2021 to 30 June 2022. Of these events, 72 (63%) had either photos or videos that could be assessed to confirm taxa identification and other information. The remaining 43 (37%) events had no photos associated with them and were therefore not able to be assessed. There is some discussion of potential reasons for a lack of photos within the report.

Taxon identification by observers was confirmed as correct in almost all events where reasonable quality photos were available.The only exception to this was the expert identification of a WHT (dolphins and toothed whales [unidentified]), which was identified by the observer as WHU (whale unspecified).

Publication information

Johnston O, Pavanato, H. (2023). Identification of marine mammals captured in New Zealand fisheries 2021-22. INT2020-02 final report prepared by Cawthron Institute for the Department of Conservation. 25 p.