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FROM INDIVIDUALS TO POPULATIONS: PREY FISH RISK‐TAKING MEDIATES MORTALITY IN WHOLE‐SYSTEM EXPERIMENTS
Author(s) -
Biro Peter A.,
Post John R.,
Parkinson Eric A.
Publication year - 2003
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/02-0416
Subject(s) - predation , foraging , trout , ecology , trade off , cannibalism , biology , population , habitat , fish <actinopterygii> , fishery , demography , sociology
Recent research suggests that the behavior of individuals under risk of predation could be a key link between individual behavior and population and community dynamics. Yet existing theory remains largely untested at large spatial and temporal scales. We manipulated food available to age‐0 rainbow trout while at risk of cannibalism, in a replicated factorial whole‐lake experiment, to test whether the trade‐off between growth and mortality rates is mediated by foraging activity by young fish under predation risk. We found that this trade‐off exists for young fish at the whole‐system scale, and that food‐dependent behavioral variation has large mortality consequences. In high‐food lakes, age‐0 trout spent less time moving, fewer individuals swam continuously, and those swimming continuously swam at slower speeds relative to those in low‐food lakes. Age‐0 trout also used deep, risky habitats less when food was abundant. This lower activity, combined with avoidance of risky habitats, coincided with 68% higher survival in high‐food lakes. If general, this trade‐off may be a key mechanism linking individual behavior to population‐level processes in size‐structured populations.