Natural Hybridization between Black Crappie and White Crappie in Weiss Lake, Alabama

Abstract

Starch-gel electrophoretic analysis of 1,081 crappies collected from October 1990 through November 1991 revealed that black crappie Pomoxis nigromaculatus and white crappie P. annularis were hybridizing in Weiss Lake, Alabama. Crappie hybrids made up 22% of the population and were found in the 1988 to 1991 year-classes. First-generation (F1) hybrids were seven times more abundant than second-generation and higher (Fx) hybrids. The F1 hybrids expressed superior growth and survival, and they recruited into the fishery (254-mm total length minimum size limit) earlier than the parental species. Distributions of alleles among Fx hybrids indicated that F1 hybrids were more likely to successfully mate and produce offspring with black crappies than with white crappies. Factors that may have contributed to hybridization between crappie species include failure to identify specific mates due to low water clarity during spring when these fish spawn, short and overlapping spawning times, and fluctuating water levels. In addition, Weiss Lake is located at the interface of sympatric and allopatric crappie populations and this has been associated with interspecific hybridization among other fish species.