Hybridization between Redeye Bass and Smallmouth Bass in Tennessee Streams

Abstract
To enhance headwater stream fisheries, nonindigenous redeye bass Micropterus coosae were introduced into 16 north-central Tennessee streams from the mid 1950s through the early 1960s. Reassessment occurred from June 1994 to October 1995 by sampling 18.6 km of stream channel in 31 streams by backpack electrofishing. Meristic criteria identified redeye bass in 11 streams within three river drainages and hybrids (redeye bass × smallmouth bass M. dolomieu) in 20% of the Micropterus spp. sampled in 6 streams within two river drainages. Based upon electrophoretic criteria, hybrid genotypes were identified in 66% of the Micropterus spp. collected from 9 of 31 streams sampled. Introgression is highly probable in the Ocoee, Obed, and Roaring river systems. These hybridizing populations illustrate the consequences of introducing nonindigenous redeye bass into streams containing indigenous smallmouth bass.