Evol Ecol Res 4: 871-881 (2002)     Full PDF if your library subscribes.

Seasonal variation in catch-up growth reveals state-dependent somatic allocations in salmon

Neil B. Metcalfe,¹ Colin D. Bull¹‡ and Marc Mangel²*

¹Fish Biology Group, Division of Environmental and Evolutionary Biology, Graham Kerr Building, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK and ²Department of Applied Mathematics and Statistics, Jack Baskin School of Engineering, University of California, Santa Cruz, CA 95064, USA

Author to whom all correspondence should be addressed.
e-mail: msmangel@cats.ucsc.edu

ABSTRACT

The trade-off in the allocation of resources between skeletal growth and the storage of reserves has received little attention, despite relevance to all growing organisms. We explored this trade-off by manipulating food availability for juvenile Atlantic salmon, Salmo salar, so as to create the same reduction in growth and loss of energy reserves at different times of the year. The fish showed seasonal differences in their responses to the nutritional deficit when food was restored. In winter, fish restored lipid reserves, but their growth in length over the recovery period was negligible. In summer, fish allocated resources to growth in length as well as the restoration of lipid reserves; moreover, this skeletal growth was significantly faster than that of control fish that had received food ad libitum throughout. We demonstrate that current physiological and energetic models of animal growth cannot account for such seasonal variation in compensatory growth and allocation patterns, and the regulation of growth and energy reserves is a dynamic and state-dependent process. We then predict – on the basis of expected effects on fitness – how somatic allocation and catch-up growth should vary over time and in contrasting environments.

Keywords: Atlantic salmon, body size, fat reserves, growth, Salmo salar.

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        © 2002 Marc Mangel. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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