MOVEMENTS, FEEDING PERIODS, AND DAILY RATION OF PISCIVOROUS YOUNG-OF-THE-YEAR BLUEFISH, POMATOMUS SALTATRIX, IN THE HUDSON RIVER ESTUARY

Young-of-the-year (YOY) bluefish, Pomatomus saltatrix, were collected during the summers of 1992 and 1993 in the Hudson River estuary with b each seine, surface trawl, and gill nets. The temporal and spatial pat terns of catch-per-unit-of-effort (CPUE) and gut-fullness values were used to infer bluefish movement and feeding periods, respectively. Est imates of daily ration were made from gut-fullness values and previous ly published estimates of gastric evacuation rate. Nearshore beach-sei ne CPUE was highest during day collections and lowest at night. Offsho re gill-net CPUE was highest during crepuscular or night periods and l owest during day sets. Hence, YOY bluefish appear to occupy nearshore environments during the day and move away from shore at night. Gut-ful lness values for bluefish captured with beach seines were highest at d iurnal and crepuscular periods and declined at night; however, there w ere indications of night feeding on some dates. The magnitude and patt ern of daily ration estimates of YOY bluefish in the Hudson River estu ary were similar to values measured in previous studies with other met hods. Interannual differences in the magnitude of daily ration were ob served and may be a result of day-today variation in feeding or differ ences in available prey type and size. Clupeids, striped bass, and bay anchovy were important prey in 1992, whereas striped bass, bay anchov y, and Atlantic silversides were the dominant prey of YOY bluefish in 1993. Improved understanding of the spatial and temporal patterns of b luefish feeding, as well as fine-scale temporal resolution of estimate s of bluefish consumption rates, will aid in assessing the impact of Y OY bluefish predation on fish populations within the Hudson River estu ary.