Many centrarchids and percids are near or at the top of the food chain in their habitats. Largemouth bass and walleye, for example, are typically top predators, feeding on herbivorous as well as smaller carnivorous fishes. Even the much smaller yellow perch and bluegill are primarily carnivorous and will take invertebrates and minnows. Centrarchids also include a number of specialized mollusk-feeding forms, such as the longear and the red-ear (Lepomis microlophus) sunfishes. Many centrarchids and percid species are known as crepuscular feeders, but anglers often take considerable numbers of
these species at midday (although fishing does peak around dawn and dusk).
Some centrarchids are also known to alter their feeding ecology depending on the species composition of their neighbors. Bluegills living in waters with predatory largemouth basses, for instance, are more likely to forage in weeds rather than in open water. This action may protect them from the jaws of a bass, but it also limits their ability to find food. Additional studies of bluegill and pumpkinseed sunfishes report that they will shift their diet to zooplankton or bottom-dwelling prey in deference to the apparently dominant green sunfish (L. cyanellus) when all three occur together. Elasso-matids and moronids are also carnivorous. Both eat invertebrates, especially crustaceans, and adult moronids are also piscivorous.
Predation on the species within these four families is primarily by larger piscivorous fishes. For example, northern pike (Esox lucius) will eat even quite large yellow perch, which will, in turn, feed on smaller fishes. Other predators of shallow water fishes include piscivorous birds, such as herons and ospreys.
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