Mesozooplankton of Shelikof Strait, Alaska: abundance and community composition

Zooplankton was sampled in Shelikof Strait and some of the surrounding shelf waters from March to October 1985, and then in Shelikof Strait during spring 1986–1989, using 150 and 333 μm mesh nets. The median integrated abundance of copepods in spring was 1–2 orders of magnitude greater in the Strait (maximum depth >250 m) than over shallower, adjacent regions of continental shelf. Zooplankton fauna was a mixture of oceanic and continental shelf taxa, and among the copepods was strongly influenced by abundance of two deep-water species,Neocalanus plumchrus andMetridia pacifica Seasonal development of the copepod community in Shelikof Strait followed similar patterns over the 5-year period. Biomass of copepods showed some large interannual differences related mostly to abundance of the oceanic taxa. Large interannual differences were found for some of the other zooplanktonic taxa as well, but there did not appear to be any correspondence between the patterns shown by these groups and those shown by the copepods. Although euphausiids were not quantitatively sampled, the taxonomic composition and relative abundance and seasonality of species within this group are reported.