Identification of marine mammals captured in NZ fisheries 2016/17
Introduction
This the annual report on the identification of marine mammals captured in New Zealand fisheries in 2016/17 (1 July 2016 - 30 June 2017). Published November 2019.Download the publication
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 162 marine mammal bycatch events reported between 1 July 2016 to 30 June 2017 (Table 1). Of these events, three (2%) events had photos but which were of insufficient quality to confirm species identity and 113 (70%) had photos that could be assessed to confirm taxa identification and other information. The remaining 46 (28%) 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.
Taxa identification by observers was confirmed as correct in all but one bycatch event where reasonable quality photos were available (Table 2). In this one event, the observer identified the event as CDD (common dolphin) but the expert confirmed it as a DDO (dusky dolphin).
Publication information
Childerhouse S, Johnston O. 2019. INT2017-03: Identification of marine mammals captured in New Zealand fisheries 2016/17. Prepared for the Department of Conservation. Cawthron Report No. 3422. 20 p.