Spatial Overlap and Competition in Congeneric Surfperches (Embiotocidae) off Santa Barbara, California

Abstract

Spatial overlap was studied in two pairs of congeneric embiotocid fishes which live in and about beds of giant kelp off Santa Barbara, California. In the morphologically least divergent pair (Embiotoca jacksoni and E. lateralis), spatial interaction is minimized; the species tend to associate with different structural features of the habitat. The congeners with relatively great morphological differences (Rhacochilus toxotes and R. vacca) show substantial spatial overlap. A division of spatial resources may effectively reduce competition in the Embiotoca species, which exploit broadly overlapping food resources. The Rhacochilus species, which differ markedly in diet, apparently can overlap spatially to a much greater extent without interference.