Zooplankton Abundance and Biomass Retrospective

Samples were taken during late spring and late summer of three years: 1997, a year of moderate spring ice cover and unusually warm, calm summer conditions; 1998, a year of warm, but stormy summer conditions with very little spring ice cover; and 1999, a year of extensive spring ice cover, cold spring conditions and storms during spring and summer.

Mean water column temperature was significantly lower during June 1999 than June 1998 and 1997. Copepod abundance and biomass during June were correlated with mean water column temperature and mean temperature below the thermocline. Mean calanoid abundance during June 1999 was 8 - 52 % of the mean abundance during 1998 and 1997.