Abundance and biomass of sub-ice mesozooplankton in the Pechora and Kara Seas in January-April 2000

Sampling was carried out from onboard nuclear ice breakers in the period January-April 2000. Breeding of a small-size opportunist species Pseudocalanus acuspes under continuous fast ice of the Gulf of Yenisei began as early as in April, though total mesozooplankton biomass (0.8 mg/m**3) was characteristic of winter condition of community.

A classical spring pattern of polychaete and barnacle larvae hatching and euphausiid spawning was observed. Such conditions of the zooplankton community near the ice edge had been described earlier, but this was the first observation of a planktonic community under continuous ice of the Kara Sea.