Variation in foraging tactics of fishes

Abstract

Synopsis Changes in feeding tactics over short intervals and variation among individuals have often been ignored or treated as ecological 'noise'. This paper reviews foraging variability in fishes and discusses its sources and consequences. Evidence is accumulating that individuals in many populations differ substantially in physiological, morphological, and behavioral characteristics. Short-term (within individual) variation includes changes in strike pattern with prey type, reversals in preference during feeding trials, and shifts in the extent of realization of an optimal diet. Documented cases of variation among individuals include differences in the time required to respond to new prey, the tendency to switch to abundant prey, foraging stance, feeding location, and in parameters describing the functional response. Such variation appears to be a general phenomenon, bearing directly on ecological questions such as resource partitioning, optimal foraging, population structure and community organization.