A Taxonomic Study of Esox americanus and Its Subspecies in Eastern North America

Abstract

Examination of the range-wide variation in 13 morphological characters, of biology, of color pattern and three anatomical features of the redfin and the grass pickerels showed them to be subspecifically distinct. For each of these subspecies, Esox a. americanus Gmelin and E. a. vermiculatus LeSueur, there are areas within which values for various characters are uniform and these areas delineate their ranges along the Atlantic coast and in the Mississippi River-Great Lakes watersheds. They do, however, intergrade across a broad front in the Gulf of Mexico region from the St. Johns River in Florida, to the Biloxi River, Mississippi. In this region it is impossible to assign individuals to either form. Over the areas of uniformity, the forms can be distinguished on the basis of two snout proportions, two scale characteristics, and, probably, color in young. Values overlap for other characters studied. The synonymy is reviewed and details of distribution are given.