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Davidsen JG, Bordeleau X, Eldøy SH, Whoriskey F, Power M, Crossin GT, Buhariwalla C, Gaudin P. Marine habitat use and feeding ecology of introduced anadromous brown trout at the colonization front of the sub-Antarctic Kerguelen archipelago. Sci Rep 2021; 11:11917. [PMID: 34099778 PMCID: PMC8184814 DOI: 10.1038/s41598-021-91405-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/26/2021] [Indexed: 11/29/2022] Open
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.
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Affiliation(s)
- Jan Grimsrud Davidsen
- NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway.
| | - Xavier Bordeleau
- Department of Biology, Dalhousie University, Halifax, NS, Canada.,Department of Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli, QC, G5H 3Z4, Canada
| | | | - Frederick Whoriskey
- Ocean Tracking Network, Dalhousie University, 1355 Oxford St., Halifax, NS, B3H 4R2, Canada
| | - Michael Power
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Glenn T Crossin
- Department of Biology, Dalhousie University, Halifax, NS, Canada
| | - Colin Buhariwalla
- Nova Scotia Department of Fisheries and Aquaculture, Pictou, NS, Canada
| | - Philippe Gaudin
- Université de Pau et des Pays de l'Adour, e2s UPPA, INRAE, ECOBIOP, Aquapôle INRAE, Saint-Pée-sur-Nivelle, France
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