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Thermal performance of Arctic charr

intraspecific variation and competitive ability

Larsson, Stefan (2002). Thermal performance of Arctic charr. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Silvestria, 1401-6230 ; 251
ISBN 91-576-6335-1
[Doctoral thesis]

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Under experimental conditions, I have studied and compared the thermal performance of several geographically separated wild Arctic charr populations. In addition, I have studied the preferred temperatures of charr and brown trout. Fish were reared both singly and in groups. The data were analysed and fitted to baseline models in order to estimate the growth efficiency as well as the lower, the upper and the optimum temperatures for growth and feeding of charr. Overall, the optimum temperature for feeding and growth of charr was found in the range 14-17°C and only slight differences was found between populations. The lower and upper limit for feeding and growth were estimated at about 2-3°C and 21-22°C, respectively. The upper limits and the optimum temperatures for growth and feeding are clearly higher than suggested in previous studies. The unexpected high lower limit may result from fish being acclimatised to summer conditions and the rather short (14 days) experimental periods. Charr had remarkably high growth efficiency that varied between 40-60%. The growth efficiency was only moderately affected by temperature. The preferred temperature of charr was found to be 11.4°C, which is about 3.5°C lower than the temperature for maximum growth. This was significantly lower than for trout, which selected a temperature of 16.0°C. Thus, charr thermoregulation strongly contradicts the general rule of coincidence of preferred temperature and optimum temperature for growth of fish, while brown trout obeys it. This finding might partly explain why charr and trout are niche segregated, when they exists in sympatry. The summer temperature in the littoral of lakes containing sympatric charr and trout generally exceeds the preferred temperature of charr, which then will move to cooler and deeper areas. Today, the Arctic charr in Scandinavia appears to be on the southern edge of its distribution. Perturbations of the thermal environment of charr (e.g. hydroelectric power plants, nuclear power plants or forestry actions and global climate change) might escalate the erosion of charr habitats. The findings of this study can be used as a tool in order to identify and manage threatened habitats and populations. Furthermore, this basic knowledge of the thermal performance of charr could be used to improve the management of charr under farming conditions.

Authors/Creators:Larsson, Stefan
Title:Thermal performance of Arctic charr
Subtitle:intraspecific variation and competitive ability
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Silvestria
Year of publishing :January 2002
Number of Pages:24
ALLI. Larsson, S. & Berglund, I. (1998). Growth and food consumption of 0+ Arctic charr fed pelleted or natural food at six different temperatures. Journal of Fish Biology 50, 230–242. II. Thyrel, M., Berglund, I., Larsson, S. & Näslund, I. (1999). Upper thermal limits for feeding and growth of 0+ Arctic charr. Journal of Fish Biology 55, 199-210. III. Larsson, S. & Berglund, I. Effects of temperature on energy intake, growth and growth efficiency of four Arctic charr populations. Manuscript. IV. Berglund, I., Forseth, T., Larsson, S., Jensen, A.J., Näslund, I., Elliott, J.M. & Jonsson, B. Thermal adaptation of Arctic charr – experimental studies of growth in eleven charr populations from Sweden, Norway and Britain. Manuscript. V. Larsson, S. Niche segregation of Arctic charr and brown trout – a result of different thermo-regulatory behaviour? Manuscript.
Place of Publication:Umeå
ISBN for printed version:91-576-6335-1
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:M Aquatic sciences and fisheries > M40 Aquatic ecology
Subjects:Not in use, please see Agris categories
Agrovoc terms:salvelinus alpinus, salmo trutta, temperature, adaptation, growth, models, feeding, thermoregulation, nature conservation, fish culture
Keywords:thermal adaptation, Salvelinus alpinus, Salmo trutta, growth model, diet, food conversion, thermal limits
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ID Code:126
Department:(NL, NJ) > Institutionen för vattenbruk (990101-061231)
Deposited By: Staff Epsilon
Deposited On:08 Jan 2003 00:00
Metadata Last Modified:02 Dec 2014 10:01

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