Food, Age, Growth, and Morphology of the Blackbanded Sunfish, Enneacanthus c. chaetodon, in Smithville Pond, Maryland

Abstract

A total of 322 specimens of the blackbanded sunfishEnneacanthus c. chaetodon, was collected during two separate drainings of Smithville Pond, on the Coastal Plain, Caroline County, Maryland. Ninety, 30 from the November 1955 and 60 from the July 1958 samples, were examined to ascertain age, growth body proportions, food and sexual dimorphism. Body proportions approached those noted for the recently described southern subspeciesE. c. elizabethae. No morphological or growth differences were found between males and females in either sample. Lengths of 43–53 mm were attained in about four years. Wide differences occurred, between samples, in the calculated lengths for ages 1 and 2 while those for ages 3 and 4 were more similar. Further investigation will determine whether these data exhibit populations which reflect extremes of growth-environment interplay or an unreliability in the scale method of determining age and growth for this species. Chironomids (summer) and caddis fly larvae (fall) were prominent food items.