Marine habitat use and feeding ecology of introduced anadromous brown trout at the colonization front of the sub-Antarctic Kerguelen archipelago

Jan Grimsrud Davidsen, Xavier Bordeleau, Sindre Håvarstein Eldøy, Frederick Whoriskey, Michael Power, Glenn T. Crossin, Colin Buhariwalla, Philippe Gaudin

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

In 1954, brown trout were introduced to the Kerguelen archipelago (49°S, 70°E), a pristine, sub-Antarctic environment previously devoid of native freshwater fishes. Trout began spreading rapidly via coastal waters to colonize adjacent watersheds, however, recent and unexpectedly the spread has slowed. To better understand the ecology of the brown trout here, and why their expansion has slowed, we documented the marine habitat use, foraging ecology, and environmental conditions experienced over one year by 50 acoustically tagged individuals at the colonization front. Trout mainly utilized the marine habitat proximate to their tagging site, ranging no further than 7 km and not entering any uncolonized watersheds. Nutritional indicators showed that trout were in good condition at the time of tagging. Stomach contents and isotope signatures in muscle of additional trout revealed a diet of amphipods (68%), fish (23%), isopods (6%), and zooplankton (6%). The small migration distances observed, presence of suitable habitat, and rich local foraging opportunities suggest that trout can achieve their resource needs close to their home rivers. This may explain why the expansion of brown trout at Kerguelen has slowed.

Original languageEnglish
Article number11917
JournalScientific Reports
Volume11
Issue number1
DOIs
Publication statusPublished - Dec 2021

Bibliographical note

Funding Information:
The project was financed by the French Polar Institute (IPEV, Institut Polaire Paul-Emile Victor) as a part of the SALMEVOL program and the LTSER (Zone Atelier Antarctique et Terres Australes), with additional support from the NTNU University Museum and Dalhousie University’s Ocean Tracking Network. We especially thank Lucie Aulus, Mathieu Buoro, Jacques Labonne, Clément Rio, Jessy Monod and Armand Patoir for assistance with field work and Aurélie Manicki for genetic analyses Stable isotope analyses were supported by an NSERC Discovery Grant to MP. Stomach contents were analysed by Lars Rønning and aging was done by Aslak Darre Sjursen. Thanks to Lucie Aulus-Giacosa for providing Fig. 1 and to Marc Daverdin with Fig. 2. The logistical support provided by the Terres Australes et Antarctiques Françaises administration and the Southern French Natural Reserve at Kerguelen was invaluable, and much appreciated as well was the help and support of the IPEV logistics team at Kerguelen.

Publisher Copyright:
© 2021, The Author(s).

ASJC Scopus Subject Areas

  • General

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't

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