Abstract

Procambarus acutus acutus (eastern white river crayfish) replaced P. clarkii (red swamp crayfish) in experimental culture ponds in South Carolina in < 10 years. Follow-up competition experiments indicated that the body size of P. a. acutus was important in defining the interaction between the two species. Species chela lengths and widths were compared using carapace length as a covariate. Male chela lengths and widths were significantly larger than their female conspecifics. Male P. a. acutus had significantly longer chelae than male P. clarkii while female P. a. acutus chelae were longer than female P. clarkii, but this difference was not significant (P < 0.10). Chela size in concert with differential body size contributed to the P. clarkii replacement by P. a. acutus.