P. A. Klose, S. B. Brandt, and K. H. Hartman, Great Lakes Center at Buffalo State College, 1300 Elmwood Avenue, Buffalo, NY

Abstract. Bay anchovy (Anchoa mitchilli) are one of the most abundant fish species in Atlantic coastal waters and in many east coast estuaries. Bay anchovy play an important role in the food web of the Hudson River Estuary both as a size selective zooplanktivore and major prey of recreationally and commercially fished piscivores. Measures of bay anchovy abundances in the Hudson River Estuary are not available. We used high-frequency (120 kHz), split-beam echo sounding to assess the abundance and spatial distribution of bay anchovy from May to September 1996 and 1997 in the Hudson River Estuary from Newburgh, NY to Sandy Hook, NJ. Composition of acoustic targets was determined from midwater trawl catch data. The estuary was divided into 15 geographic regions from north to south. Distributions and densities of anchovy were determined from acoustic sampling for each geographic region for each month and compared to the prevailing environmental conditions. Preliminary results have shown significant differences between distributions of larval and adult bay anchovy. The highest densities of larval anchovy occurred near Indian Point in August while peak densities of adults were found in the Yonkers region in July.