University Of Tasmania

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Dusky dolphins influence prey accessibility for seabirds in Admiralty Bay, New Zealand

journal contribution
posted on 2023-05-19, 11:13 authored by Vaughn, RL, Wursig, B, Shelton, DS, Timm, LL, Leslie WatsonLeslie Watson
Although seabirds frequently aggregate with feeding delphinids, the benefits to seabirds of feeding with dolphins have been rarely reported. We examined how dusky dolphins (Lagenorhynchus obscurus) influenced prey accessibility for seabirds in Admiralty Bay, New Zealand. Interactions of dusky dolphins and seabirds were characterized during 335 feeding bouts of dusky dolphins (52 video-recorded underwater). Dolphins increased prey accessibility for seabirds because they swam under the bottom half of prey balls for 59% of passes that were within 2 m of the prey ball. During feeding bouts by dolphins, 51% of prey balls ascended, whereas only 13% descended. Dolphins also influenced prey mobility; only 24% of stationary feeding bouts became mobile after dolphins began feeding, and 17% subsequently became stationary again. Significantly more Australasian gannets (Morus serrator) were near mobile than stationary prey balls after feeding, but not during feeding bouts. This suggests that feeding gannets increase mobility of prey balls, but that feeding dolphins counteract this effect. Seabirds also used dusky dolphins to locate prey. Numbers of gannets, shearwaters (Puffinus), and gulls (Larus) increased during the first 2 min of dolphin feeding, even when other seabirds were not present. Gannets fed with dolphins for 40% of gannet feeding observations and shearwaters fed with dolphins for 24% of shearwater feeding observations.


Publication title

Journal of Mammalogy










Institute for Marine and Antarctic Studies


Alliance Communications Group Division Allen Press

Place of publication

810 East 10Th Street, Lawrence, USA, Ks, 66044

Rights statement

Copyright 2008 American Society of Mammalogists

Repository Status

  • Restricted

Socio-economic Objectives

Marine biodiversity