Effects of Species Introductions on Salmonid Communities in Oligotrophic Lakes

Abstract
Adequate documentation was often wanting for interpretation of conditions surrounding the success or failure of an exotic. There were also known differences in species composition and other circumstances which made comparisons between SCOL lakes difficult.Successful colonization appeared possible where a sufficiently plastic new species found a niche either temporarily or permanently void. The lack of normal ecological constraints favored the explosion of a colonist, and examples were found which indicated both physiological and behavioral adaptation to permit establishment. The data suggested predation may be important in suppressing invaders. The higher diversity of littoral fish communities provided greater resistance to colonists. The role of exploitation in the fate of any colonist seemed chiefly in its effect on diversity and on stock oscillations. Eutrophication favored the success of colonists through continued destabilization of communities. It was suggested that management should proceed towards greater diversity to minimize the chances of outbreaks of pest fishes.

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