Despite the accumulated evidence that rapid climate change has deleterious effects on a broad range of animal populations, there are few data indicating how these effects are mediated. Biro et al. conducted a field experiment by stocking nine small lakes in British Columbia with trout in the warm summer of 1998 and in the cool summer of 1999. They found that water temperatures above 17.5°C increase the metabolic rate of young rainbow trout, so in order to maintain their rate of growth, the young fish compensate by feeding more actively. It became apparent that the increased feeding activity increased the young trout's visibility to predators (usually adult trout), such that the survival of the young in a warm year was only half that in a cooler year. Hence, the small increases in water temperature (of just a few degrees) caused by climate change will substantially reduce the survival of lake trout populations for which escape by migration is not possible. -- CA
Proc. Natl. Acad. Sci. U.S.A. 104, 9715 (2007).
