Dear Marmamers,
I am pleased to announce the release of this new article on the feeding ecology of Fiordland bottlenose dolphins:
Lusseau, S.M. and S.R. Wing. 2006. Importance of local production versus pelagic subsidies in the diet of an isolated population of bottlenose dolphins Tursiops sp. Marine Ecology Progress Series 321:283–293
ABSTRACT:
Isolated populations can be strongly influenced by patterns in the local production of food, and by subsidies from outside sources. We used stable-isotope analysis to investigate the relative importance of autochthonous food resources versus pelagic subsidies in the diet of the isolated population of bottlenose dolphins Tursiops sp. inhabiting Doubtful Sound, New Zealand. Samples of the primary carbon sources (macroalgae, phytoplankton and chemoautotrophs) as well as potential food sources (fish and squid) were collected from Doubtful Sound and analysed for δ13 C and δ15N. Isotopic signatures of fishes fell along a gradient from very depleted values for deep benthic species, particularly hagfish Eptatretus cirrhatus ( δ13C –23.6, δ15N 6.3), to intermediate values for pelagic species (δ13C –18.1, δ 15N 11.3) and more enriched values for reef-associated species (δ13C –16.1, δ15N 14.4). Exfoliated skin tissue was collected from live dolphins (n = 11) and used to estimate the isotopic signature of dolphin diet (δ13C –15.4, δ15N 14.2). The position of this estimate at the most enriched end of the range of isotopic signatures indicated that there was likely minimal mixing of resources from different habitats and that a majority of the dolphin population's diet came from rocky reef and demersal habitats. Estimates of δ13C and δ15N for dolphin diet were compared with isotopic signatures of the different primary carbon sources using a multiple-source mixing model. Both results suggest that the diet of this population was primarily made up of autochthonous carbon production with a large contribution from benthic macroalgae, rather than pelagic subsidies from outside of the Sound.
The paper is available from the journals webpage:
http://www.int-res.com/abstracts/meps/v321/
Best wishes
Susan
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Susan Mærsk Lusseau, M.Sc.
Department of Biology
Dalhousie University
1355 Oxford St.
Halifax
Nova Scotia
CANADA B3H 4J1
Email: smaersk at gmail.com
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