Clinton A.J. Duffy

Department of Conservation, Auckland War Memorial Museum

C. Scott Baker

Oregon State University

Rochelle Constantine

University of Auckland

Published

16 October 2015

Handle

www.aucklandmuseum.com/research/pub/bulletin/20/23

Abstract

Marine mammals were observed on 46 occasions during two expeditions to the Kermadec Islands in 2004 and 2011. Species richness was greatest over the upper slope of the Bay of Plenty in May 2011, whereas abundance was greatest at the Kermadec Islands in November 2004. Diversity of cetaceans at the Kermadec Islands appears to be low however a systematic survey of the region is required to confirm this. Insular shelf waters and possibly sea mounts to the north of Raoul Island form an important part of the migratory corridor of southbound humpback whales (Megaptera novaeangliae) between mid-August and the end of November. Photo-identification, biopsy sampling and satellite tagging are required to determine source populations and habitat use by these whales. The identity of bottlenose dolphins occurring at the Kermadec Islands is confirmed as Tursiops truncatus based upon external morphology and mitochondrial DNA obtained from a single individual. Differences in size and behaviour of bottlenose dolphins observed at the Kermadec Islands mean collection of additional biopsy samples is required to confirm whether more than one species is present and to investigate if Kermadec bottlenose dolphins are genetically isolated from other South Pacific populations. While a number of species may migrate through the archipelago, the region may be unable to sustain large resident populations of cetaceans due to low pelagic primary productivity.

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