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Dusky Dolphin and Australasian Gannet Feeding Interactions in New Zealand
Citation
Vaughn, R and Markowitz, T and Shelton, D and Timm, L and Watson, L and Wursig, B, Dusky Dolphin and Australasian Gannet Feeding Interactions in New Zealand, 16th Biennial Conference on the Biology of Marine Mammals, 12-16 December 2005, San Diego, pp. 291. (2005) [Conference Extract]
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Official URL: https://www.marinemammalscience.org/conference/pas...
Abstract
There is increasing overlap between feeding habitats of marine mammals
and seabirds and the human interests of fishing, aquaculture, and
recreation. A better understanding of foraging ecology and interactions
between apex predators will facilitate advice on management/conservation
strategies. Feeding interactions between dusky dolphins (Lagenorhynchus
obscurus) and Australasian gannets (Sula serrator) in the Inner Admiralty
Bay, New Zealand provide an opportunity to study multiple-species use
of habitat, and interaction dynamics. This study examines habitat use,
feeding tactics, and feeding interactions of dusky dolphins and Australasian
gannets in the Inner Admiralty Bay. Information from boat-based research
indicates that while dusky dolphins feed on schooling fish (mainly pilchard,
Neopilchardus sp.) during the Winter in Admiralty Bay, gannets represent
the most commonly-present bird species. As in Argentina, groups of dusky
dolphins in Admiralty Bay surround schools of fish, apparently herding
them into tighter aggregation to increase foraging efficiency. Australasian
gannets are often observed circling above and diving into these fish
aggregations. It is possible that the dolphins and birds work together,
forming a commensal relationship, and using one another to more
efficiently find and/or capture prey. Alternatively, the relationship may
be a kleptoparasitic one, in which the gannets and other bird species make
use of the prey resources made more available by the hunting activity of
the dolphins, but with little or no advantage to the dolphins. We compare
estimated costs and benefits of feeding alone versus in multispecies
aggregations for dusky dolphins and Australasian gannets. Data used in
this analysis include prey capture rates, dive and success rates, length of
feeding bouts, and the numbers of dolphins and gannets present when the two species feed together versus alone.
Item Details
Item Type: | Conference Extract |
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Keywords: | Dusky dolphins, Australasian Gannets, feeding, New Zealand |
Research Division: | Biological Sciences |
Research Group: | Ecology |
Research Field: | Marine and estuarine ecology (incl. marine ichthyology) |
Objective Division: | Environmental Management |
Objective Group: | Marine systems and management |
Objective Field: | Marine biodiversity |
UTAS Author: | Watson, L (Dr Leslie Watson) |
ID Code: | 129353 |
Year Published: | 2005 |
Deposited By: | Strategic Research Funding |
Deposited On: | 2018-11-26 |
Last Modified: | 2018-11-26 |
Downloads: | 0 |
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