Experimental assessment of the bioenergetic and behavioural differences between two morphologically distinct populations of Arctic char (Salvelinus alpinus)

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Guénard, Guillaume, Boisclair, Daniel, Ugedal, Ola, Forseth, Torbjørn, Jonsson, Bror, Fleming, Ian A.
• Other Authors: Tonn, William
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2010
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Arctic; Salvelinus alpinus
• Online Access: http://dx.doi.org/10.1139/f10-004; http://www.nrcresearchpress.com/doi/full-xml/10.1139/F10-004; http://www.nrcresearchpress.com/doi/pdf/10.1139/F10-004

A common environment experiment was conducted to assess the magnitude of the difference in growth, consumption, activity rate, and spatial and temporal patterns of habitat use between morphologically different populations of Arctic char ( Salvelinus alpinus ) originating from two Norwegian lakes. These two lakes contrasted sharply in terms of surface area, depth, elevation, length of the winter period, and fish community structure (presence–absence of brown trout, Salmo trutta ). The experimental framework encompassed four littoral enclosures (average volume, 146 m 3 ) stocked with char from either of the two populations with duplicated treatments. Char morphology was quantified with numerical image analysis, food consumption was estimated using caesium analysis ( 133 Cs), and activity cost and patterns were determined using video cameras. Char populations were morphologically distinct and reacted differently in growth (1.9-fold difference between populations), food consumption (3-fold difference), and spatial activity patterns (20-fold difference) to the conditions prevailing in the enclosures. The results highlight that functional differences between morphologically distinct char may drive important differences in their bioenergetic and behavioural responses when exposed to similar environmental conditions. Such functional differences should be incorporated when developing habitat or trophic cascade models.