CHARACTERISTICS OF AN EDDY OVER A CONTINENTAL-SHELF - SHELIKOF STRAIT, ALASKA

During May 1990, satellite-tracked buoy, water property, and ichthyopl ankton observations were collected over the Shelikof sea valley in the western Gulf of Alaska. These observations revealed the presence of a n anticyclonic mesoscale eddy (radius 10-12 km). Characteristics of th e eddy included a relatively warm, low-salinity core and high concentr ations of walleye pollock larvae. The eddy remained nearly stationary for several weeks before moving westward into shoaler waters. During t ranslation, the eddy maintained its characteristics. Speeds from geopo tential topography and direct measurements agreed. Current speeds gene rally increased with distance from the center of the eddy; maximum spe eds (> 30 cm s-1) existed near the perimeter. Analysis of water proper ties indicates little or no exchange of mass occurred with adjacent wa ters. The lack of dispersion permits us to estimate larval mortality ( less-than-or-equal-to 4.7 % d-1) based only on biological factors. Edd y formation occurred through baroclinic instability upstream within Sh elikof Strait proper.