Food and Feeding of Young Finfish Species in the Lower Roanoke River, Batchelor Bay, and Western Albemarle Sound, NC 1982-1988 Vol. I

The goals of the study were to characterize the food web for larval striped bass and other young finfish species in the lower Roanoke River and western Albemarle Sound, North Carolina, and to ascertain if food chain interruption may be a factor contributing to poor recruitment. Striped bass recruitment to the year class forming in the nursery grounds of western Albemarle Sound has been poor relative to the numbers of eggs spawned by adult fish in the Roanoke River each year. Therefore, abnormally high mortality is occurring between egg hatch and juvenile recruitment. An inadequate food supply would result in starvation of the larvae. An inadequate supply can be the result of low numbers of prey items, inaccessibility to prey by fish larvae due to prey size or quickness, or both factors. If striped bass larvae in the Roanoke-Albemarle system are food limited, then an examination of co-habiting young flllfish species should indicate whether the food limitation is quantity, quality, or both. Those species that have diet overlap with striped bass may show greater success at feeding on preferred prey of striped bass, suggesting that striped bass are outcompeted for food resources. On the other hand, those same finfish species may show a poor feeding rate, similar to striped bass, suggesting that young finfish in the system are food limited by quantity of prey. We combined data sets on water quality, primary productivity, zooplankton, larval abundance, and larval food habits collected in the springs of 1982-1986 and 1988 to provide information spanning six years of varying seasonal and river flow patterns. The year 1987 was a flood year in which too few striped bass larvae were collected to perform food habit analyses. Collection sites were the lower Roanoke River, delta (Thoroughfare, Cashie, Middle, Eastmost, and Roanoke rivers), Batchelor Bay, and western Albemarle Sound.