| Popis: |
A total of 188 young-of-year (YOY) striped bass, Morone saxatilis, and 199 YOY white perch, Morone americana, were collected by pushnet, seine and trawl during 24-hour periods from June through August, 1992 in lower James River, Virginia. The purpose was to identify prey and temporal and spatial feeding habits. Copepods were the most numerous prey of both species. Fishes and mysids comprised the largest volumetric percentage of diets of striped bass and white perch, respectively. Using an index of relative importance, leptodorids and copepods were the most important prey of striped bass and white perch, respectively. Both species shifted from planktonic to epibenthic foods with increasing length. Diets of striped bass and white perch captured by seine were significantly more diverse than those captured by trawl. No temporal or spatial differences in feeding success were found for striped bass. White perch captured at twilight and by pushnet fed more successfully than conspecifics captured at day, or by seine or trawl, respectively. Spearman correlation coefficient, Horn's index and Shannon-Weaver index indicated that diets between striped bass and white perch were significantly correlated, highly overlapping and equally diverse, respectively. With the exception of one temporal and one spatial comparison, interspecific comparisons of feeding success were not significantly different. Results indicate that young of both species feed opportunistically. Abiotic factors appear to have little direct relationship with YOY striped bass and YOY white perch feeding success. |
