Identification and species characterization of some North American minnows by electrophoresis

The LDH and MDH phenotypes of Notropis comutus, Nocomis biguttatus, Pimephales promelas, P. notatus, Rhinichthys atratulus and Semotilus atromaculatus show no apparent intraspecific variation. All species with the exception of Notropis comutus and Rhinichthys atratulus possess unique MDH phenotypes. Those two species can be readily differentiated on the basis of their LDH phenotypes. This represents a rapid, simple, inexpensive technique for an unambiguous separation and identification of otherwise similar, closely related species.