Insights into the dynamics of fish growth can be gained by using foraging theoryto link bioenergetics models of fish and their prey. These links are critical for modeling fish daily ration and growth, prey mortality, selection among prey, and competition among predators. However, the foraging theory that is relatively well developed for planktivores does not always apply to piscivores without important modifications. Visual encounter is often limited by visual acuity for most planktivores, but probably limited by prey contrast for piscivores, so that piscivore reactive distance is much less dependent on prey size. Whereas handling time per prey may limit the capture rate for some planktivores, it is irrelevant for most piscivores, which eat relatively small numbers of large prey and are more likely to have daily ration limited by rates of digestion or prey encounter. Time for gastric evacuation of digestion should not be a part of handling time, because search can occur simultaneously with digestion.
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