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

•  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 ofArctic char (Salvelinus alpinus) originating from two Norwegian lakes. These two lakes contrasted sharply in terms of surfacearea, 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 m3) stocked withchar from either of the two populations with duplicated treatments. Char morphology was quantified with numerical imageanalysis, food consumption was estimated using caesium analysis (133Cs), and activity cost and patterns were determinedusing video cameras. Char populations were morphologically distinct and reacted differently in growth (1.9-fold differencebetween 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 charmay drive important differences in their bioenergetic and behavioural responses when exposed to similar environmentalconditions. Such functional differences should be incorporated when developing habitat or trophic cascade models.

Subject headings

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Publication and Content Type

ref (subject category)

art (subject category)