Biophysical data were collected along a primary marine migration corridor of juvenile Pacific salmon (Oncorhynchus spp.) in the northern region of southeastern Alaska. Data were collected at 13 stations in four sampling intervals (25 d total) from May to August 2002. This survey marks the sixth consecutive year of systematic monitoring, and was implemented to identify the relationships among biophysical parameters that influence the habitat use, marine growth, predation, stock interactions, year-class strength, and ocean carrying capacity of juvenile salmon. Habitats were classified as inshore (Auke Bay), strait (four stations each in Chatham Strait and Icy Strait), and coastal (four stations off Icy Point), and were sampled from the National Oceanic and Atmospheric Administration ship John N. Cobb. At each station, fish, zooplankton, surface water samples, and physical profile data were collected using a surface rope trawl (fish), conical and bongo nets (zooplankton), and a conductivity-temperature-depth profiler (physical profile), usually during daylight. Surface (2-m) temperatures and salinities ranged from 6.1 to 13.9EC and 17.4 to 32.2 PSU from May to August. A total of 8,665 fish and squid, representing 21 taxa, were captured in 75 rope trawl hauls from June to August. Juvenile salmon comprised 61% of the total catch and occurred frequently in the trawl hauls, with coho (O. kisutch) occurring in 65% of the trawls, pink (O. gorbuscha) in 57%, chum (O. keta) in 55%, sockeye (O. nerka) in 47%, and chinook salmon (O. tshawytscha) in 21%. Of the 5,336 salmonids caught, more that 98% were juveniles. Walleye pollock (Theragra chalcogramma) and crested sculpin (Blepsias bilobus) were the only non-salmonid species that comprised more than 1% of the total catch. Temporal and spatial differences were observed in the catch rates, size, condition, and stock of origin of juvenile salmon species, and in predation rates on them. Catches of juvenile chum, pink, sockeye, and coho salmon were generally highest in July, whereas catches of juvenile chinook salmon were highest in June. By habitat type, juvenile salmon catches were highest in straits. In the coastal habitat, catches were highest within 40 km of shore. Size of juvenile salmon increased steadily throughout the season; mean fork lengths in June and August were respectively: 86 and 143 mm for pink, 96 and 145 mm for chum, 121 and 139 mm for sockeye, 153 and 235 mm for coho, and 201 and 235 mm for chinook salmon. Coded-wire tags were recovered from 20 juvenile and immature salmon; most were from hatchery and wild stocks of southeastern Alaska origin; however, juvenile chinook and coho salmon from the Columbia River Basin were also recovered. In addition, otoliths were examined from four species of juvenile salmon: 1,525 from chum, 248 from sockeye, 363 from coho, and 18 from chinook salmon. Alaska hatchery stocks were identified by thermal marks from 44% of the chum, 17% of the sockeye, 5% of the coho, and 61% of the chinook salmon. Onboard stomach analysis of 135 potential predators, representing nine species, indicated five predation instances on juvenile salmon in August, including both of the age 1+ sablefish (Anoplopoma fimbria) and 3 of 12 (25%) adult coho salmon. Our results suggest that, in southeastern Alaska, juvenile salmon exhibit seasonal patterns of habitat use synchronous with environmental change, and display species- and stock-dependent migration patterns. Long-term monitoring of key stocks of juvenile salmon, both on an intra- and interannual basis, will enable researchers to understand how growth, abundance, and ecological interactions affect year-class strength and ocean carrying capacity for salmon.