On-shelf transport of oceanic zooplankton in the Bering Sea.

Abstract

Neocalanus are zooplankton that require deep water to successfully reproduce so tend to occur in oceanic and shelf-break habitats. Shelf-break fronts in the Eastern Bering Sea reduce cross-shelf advection over the outer-shelves potentially retarding on-shelf transport of the oceanic copepods. South-Easterly winds October-May are thought to increase on-shelf flow over the southern shelf. Because Neocalanus are large-bodied with a high energy content they are an important food source for juvenile stages of commercially important fish such as pollock, capelin and salmon in the Bering Sea. Annual differences in forage and commercial fish stocks in the Bering Sea may depend on climatic and oceanographic conditions promoting on- shelf transport of Neocalanus. Timing of on-shelf transport of Neocalanus, and the key physical processes determining the degree and extent of this transport are unclear.