MORTALITY IN CALANUS GLACIALIS: SEASONAL VARIABILITY IN THE WHITE SEA BETWEEN 1963 AND 1998 Ketil Eiane

Bodo University College, 8049, Bodo, Norway

We have quantified seasonal variability in the mortality of C. glacialis in the White Sea from a data time consisting of 813 samples obtained between 1963 and 1998. Based on a vertical life table method (VLT) we developed a modified model that reduce estimate biases by relaxing assumptions of near constant recruitment and development schedules in the population under study. The approach allows for near unbiased estimates of mortality in pairs of consecutive developmental stages. We use point estimates for the combination of developmental stages CV and adult females to study seasonal variability in mortality to test for seasonal differences and trends in C. glacialis mortality rate.