S.M. Gallager, P.Alatalo, J. Van KeurenLaboratory studies have suggested that the abundance and motility of soft-bodied microplankton, as well as in situ lighting conditions, are critical to the foraging success of first-feeding larval cod (Gadus morhua). These bio-physical modulators of foraging success were quantified during a series of two cruises in 1995 and seven cruises in 1997 to Georges Bank as part of the U.S. GLOBEC North Atlantic Program. Natural motility patterns and seasonal changes in abundance of the microplankton prey field available to larvae were documented using micro-video recording, image processing and motion analysis techniques. These data, collected at various depths at the GLOBEC Georges Bank standard grid stations, are providing the required details on prey motion necessary for modeling prey encounter and feeding success in these larvae. During GLOBEC Process cruises in March and April, feeding rates at various natural light levels were obtained during in situ incubations with fluorochrome-labeled microplankton. Feeding intensity on soft- bodied protozoa by 2 to 6 day-old cod larvae was highest subsurface and dependent on light intensity. Although protozoa were ingested frequently within two days of hatching, and throughout early development, ingestion of copepod nauplii did not occur until the yolk was fully resorbed at day 10. Highlights of these results and their influence on ongoing individual-based modeling of carbon budgets and foraging in young cod will be discussed.