Pacific sand lance of the Port Moller estuary, southeastern Bering Sea: an estuarine^dependent early life history

TLDR: In this paper, the authors conclude that the Port Moller sand lance stock has an estuarine early life history that evolved in response to the unique physical conditions of the port Moller estuary, a shallow, well-mixed site with sandy substrate that is suitable for incubation of demersal eggs next to a deep, vertically stratified fjord with a rich zooplankton community.

Abstract: Three waves of spawning Pacific sand lance (Ammo-dytes hexapterus) entered the Port Moller estuary from mid-January to late May 1990 Each wave laid its eggs on sand in lower Moller Bay with the center of egg distribution about 14 km inside the estuary After incubation for 45 to 94 d, each cohort of eggs hatched out over a 41- to 63-d period Larvae moved at a rate of 021 knvd“1 toward a deep fjordlike basin at the head of Herendeen Bay inside the estuary about 20 km southwest of the center of hatch The basin has the lowest flushing rate of the estuary, and unlike the rest of Port Moller, it is vertically stratified, which allows the development of a spring-summer zooplankton community with greater biomass than any other location in the estuary Larvae may have moved to the basin to enhance growth or to avoid offshore transport to areas of low food abundance, but we cannot demonstrate a direct link between growth and habitat We conclude that the Port Moller sand lance stock has an estuarine early life history that evolved in response to the unique physical conditions of the Port Moller estuary–a shallow, well-mixed site with sandy substrate that is suitable for incubation of demersal eggs next to a deep, vertically stratified fjord with a rich zooplankton community that is suitable for rearing of larvae