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INT2017-03: Identification of marine mammals captured in New Zealand fisheries: 1 July 2015 to 30 June 2016 (PDF, 458 K)

Summary

This project forms one part of a wider Conservation Services Programme (CSP) research programme which also covers the identification of bycaught turtles and protected fish species and is designed to complement the existing seabird identification project. The accurate determination of the taxon of marine mammals captured in New Zealand (NZ) 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 capture (i.e. bycatch) on various marine mammal species.

There were 135 marine mammal bycatch events reported between 1 July 2015 to 30 June 2016 (Table 1). Of these events, 104 (77%) had photos that could be assessed to confirm taxa identification and other information (Table 2). The remaining 31 (23%) events had no photos associated with them and were there not able to be assessed. There is some discussion of potential reasons for a lack of photos within the report.

Taxa identification by observers was confirmed as correct in 100% of the bycatch events where photos were available. In one event, the observer identified the event as SEA (seal or sea lion) as only a flipper was found in the net. We confirmed this identification as it is not possible to identify the taxa from a photograph of a flipper alone.

Publication information

Childerhouse S, Johnston O. 2019. INT2017-03: Identification of marine mammals captured in New Zealand fisheries 2015/16. Prepared for the Department of Conservation. Cawthron Report No. 3422. 19 p.