We have recently found a connection between the effects of large-scale atmospheric forcing over the Gulf of Alaska and deep-water properties (temperature and salinity) below the southern sill depth (∼200 m) in Shelikof Strait, through studies under the Fisheries Oceanography Coordinated Investigations (FOCI) program. Startedin 1984, by the National Oceanic and Atmospheric Administration, most FOCI research has been conducted in Shelikof Strait, Alaska (Figure 1), a large estuarine-like system located between Kodiak Island and the Alaska Peninsula, where vast numbers of walleye pollock spawn each spring.

Although we had been aware that marked variability in the deep waters of the strait existed, a mechanism for inducing the changes was not apparent. It now seems clear that the interannual variability of upperocean circulation is large enough to bring about the water property anomalies. Figure 1 contrasts the mixed layer flows or trajectories during winter-spring of a typical year (1986) and an unusual year (1985), when southwestward outflow from the upper gulf was quite weak. These flow variations appear to result in changes in the source waters that flow over the sill to the strait, thereby causing the observed variability in properties.