Non-native Fishes Inhabiting the Streams and Lakes of Illinois

Abstract

At the turn of the century, only one non-native species of fish, the common carp, was established in Illinois (Forbes and Richardson 1908). In contrast, by 1979, six non-native fishes were reproducing in Illinois (Smith 1979) and, in 1996, only 17 years later, seven more nonnative fishes have become established (Table 1). In addition to these 13 species, 9 non-native fishes are periodically stocked in Illinois or stray into the state from nearby states where they are stocked (Table 1). Because several of these fishes only recently have become introduced or are expanding their ranges in Illinois, they are not familiar to most residents of the state. The keys and descriptions in this publication are intended to assist in the identification and monitoring of the impacts of these 22 species. Also included for each species is a brief summary of its ecological and life history characteristics, and a discussion of its Illinois distribution. Additional information can be found in accounts by Smith (1979) and by Burr (1991), who reviewed various aspects of recent changes in the fish fauna of Illinois.