Resource utilization of sympatric and experimentally allopatric cutthroat trout and Dolly Varden charr

摘要: Resource utilization by cutthroat trout (CT) and Dolly Varden charr (DV) was studied 8 years after experimental transfers from sympatry had established reproducing allopatric populations in two nearby fishless lakes. Allopatric DV significantly increased their of shallow-dwelling zoobenthos, vertical distribution comparison to that sympatry. In contrast, CT showed little change the proportions major prey types utilized, and, if anything, restricted The results can be explained hypothesis resource use is strongly influenced interspecific competition CT, whereas largely remains unaffected this interaction. An alternative hypothesis, lake differences explain between allopatry, evaluated comparing food availability other biotic abiotic characteristics three study None these could account for shift but may why a habitat with sympatric donor stock. whole-lake transfer experiment are consistent earlier reported field laboratory studies, suggest aggressive dominance most important mechanism which displaced littoral near-surface habitats sympathy CT.