Thermal adaptation of Arctic charr: experimental studies of growth in eleven charr populations from Sweden, Norway and Britain

• Published in: Freshwater biology Vol. 50; no. 2; pp. 353 - 368
• Main Authors: LARSSON, S., FORSETH, T., BERGLUND, I., JENSEN, A. J., NÄSLUND, I., ELLIOTT, J. M., JONSSON, B.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.02.2005; Blackwell Science; Wiley Subscription Services, Inc
• Subjects: adaptive variation; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; countergradient variation; food consumption; Fresh water ecosystems; Freshwater; Fundamental and applied biological sciences. Psychology; optimum temperature; Salvelinus alpinus; Synecology; United Kingdom; Great Britain; Sweden; Norway; Europe; British Isles, England; British Isles; models; adaptive variation; Growth; Experimental study; Freshwater environment; Vertebrata; Hydrobiology; Pisces; optimum temperature; food consumption; Salvelinus alpinus; Adaptation; countergradient variation
• ISSN: 0046-5070; 1365-2427
• DOI: 10.1111/j.1365-2427.2004.01326.x

Summary 1. Experimental growth data for Arctic charr (Salvelinus alpinus L.), all fed on excess rations, from 11 European watercourses between 54 and 70°N were analysed and fitted to a new general growth model for fish. The model was validated by comparing its predictions with the growth rate of charr in the wild. 2. Growth performance varied among populations, mainly because of variation in the maximum growth potential, whereas the thermal response curves were similar. The estimated lower and upper temperatures for growth varied between −1.7 to 5.3 and 20.8–23.2 °C, respectively, while maximum growth occurred between 14.4 and 17.2 °C. 3. There was no geographical or climatic trend in growth performance among populations and therefore no indication of thermal adaptation. The growth potential of charr from different populations correlated positively with fish body length at maturity and maximum weight in the wild. Charr from populations including large piscivorous fish had higher growth rates under standardised conditions than those from populations feeding on zoobenthos or zooplankton. Therefore, the adaptive variation in growth potential was related to life‐history characteristics and diet, rather than to thermal conditions.