COPEPOD POPULATIONS DURING THE SPRING BLOOM IN AN ALASKAN SUB-ARCTIC EMBAYMENT

Copepod population and biomass was monitored in Auke Bay, Alaska, during the spring bloom from 1987 to 1989. The most abundant species were Pseudocalanus spp., Oithona similis and Centropages abdominalis, with Acartia clausi reaching high concentrations in the surface waters. Although populations of Pseudocalanus were similar during all three years, C.abdominalis and O.similis concentrations were significantly higher in 1988 and lower in 1989 than in 1987. The population differences may have resulted from warmer temperatures during early spring in 1988. Substantial contributions to biomass resulted from advection of adult Calanus marshallae and Metridia ochotensis and late stage Neocalanus plumchrus into the bay. While copepod populations in Auke Bay appear to be more sensitive to factors influencing the timing and development rate of various cohorts, biomass is substantially altered by water mass movements. © 1990 Oxford University Press.