Fitness-related effects of growth investment in brown trout under field and hatchery conditions |
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| Authors: | J I Johnsson E Jöusson E Petersson T Jäurvi B Th Bjöurnsson |
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| Institution: | Department of Zoology, Göteborg University, Box 463, SE-405 30 Göteborg, Sweden;Laboratory of Streamwater Ecology, National Board of Fisheries, S-810 70 Älvkarleby, Sweden and Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, S-752 36 Uppsala, Sweden;Institute of Freshwater Research, S-170 11 Drottningholm, Sweden and Department of Zoology, Stockholm University, S-106 91 Stockholm, Sweden |
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| Abstract: | The mortality of brown trout Salmo trutta over winter in a near-natural stream was not significantly increased by growth hormone (GH) treatment, but lipid reserves were lower in GH-treated fish. As GH-treated trout grew faster than controls, GH appears to promote growth at the expense of investment in maintenance. However, the growth promoting effect of GH was much more pronounced in the hatchery than in the stream, suggesting that the pay-off associated with increased growth investment is higher under hatchery conditions with unrestricted food supply than in wild, where food availability is limited. |
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| Keywords: | ecology growth hormone Salmo trutta selection trade-off |
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