WATER COLUMN SOUND-SCATTERING AND HYDROGRAPHY AROUND THE PRIBILOF ISLANDS, BERING SEA

Water column structure around the Pribilof Islands is a complex mixtur e of salinity and temperature fronts. Elevated fluorescence and sound- scattering patterns were often observed in the upper 30 m around front al regions during both 1987 and 1988. Salinity fronts with associated elevated sound scattering were particularly intense near the surface d uring 1987. During both years sound scattering was most intense over t he shelf, decreased over the slope and was lowest over the deep basin. An epibenthic sound-scattering layer was often present but its distri bution did not appear to be related to water column structure. Water c olumn scattering patterns in 38- and 200-kHz data were similar, but ep ibenthic scattering peaks present in the 200-kHz data were absent from the 38-kHz data. Net samples indicate that a portion of the water col umn scattering was probably caused by large gelatinous zooplankton, wh ile a portion of the 200-kHz peaks in the epibenthic layers probably r esulted from sound reflected by euphausiid swarms.