Nursery areas of juvenile northern rock sole (Lepidopsetta polyxystra) in the eastern Bering Sea in relation to hydrography and thermal regimes

Age-0 and age-1 northern rock sole were collected over large-scale areas of the eastern Bering Sea in the summers of 2003, 2008 and 2010. Age-0 presence was poorly predicted by a published resource selection model developed for the Gulf of Alaska, and the failure of that model may have been caused by oceanographic features in the eastern Bering Sea. Where a front (inner front) separated the well-mixed coastal domain from the stratified middle domain, age-0 fish were less abundant and occurred at fewer stations in the nearshore, thermally mixed coastal domain than expected by the Gulf of Alaska model. In contrast, where the inner front was not established, age-0 fish were present in the highest densities in nearshore and thermally mixed waters. North of Unimak Island, the same hydrographic pattern that inhibits the formation of the inner front also likely transports larvae near shore. Age-1 densities were highest in the coastal domain, and age-0 length decreased with distance from shore, suggesting northern rock sole move shoreward after settlement. Juvenile northern rock sole were abundant in a nursery area between Nunivak Island and Cape Newenham in a warm period (2003), but were almost completely absent in cold periods (2008 and 2010), leading to the hypothesis that climate variability limits the utility of this nursery area during cold periods.