November 2019
This the annual report on the identification of marine mammals captured in New Zealand fisheries in 2017/18 (1 July 2017 - 30 June 2018).


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 115 marine mammal bycatch events reported between 1 July 2017 to 30 June 2018 (Table 1). Of these events, 82 (71%) had photos that could be assessed to confirm taxa identification and other information. The remaining 33 (29%) events had no photos associated with them and were therefore not able to be assessed. This report covers the 82 events for which reasonable photos were available. 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. Three long-beaked common dolphins (DCZ) were originally identified by the observer as common dolphins (CDD). As the DCZ is a sub-species of CDD, the CDD observer identification is correct, but is a lower taxonomic resolution.

Publication information

Childerhouse S, Johnston O. 2019. INT2017-03: Identification of marine mammals captured in New Zealand fisheries 2017/18. Prepared for the Department of Conservation. Cawthron Report No. 3422. 19 p.


Conservation Services Programme
Department of Conservation
PO Box 10-420
Wellington 6143


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