THE DEMOGRAPHY OF CALANUS-PACIFICUS DURING WINTER-SPRING CALIFORNIAN EL-NINO CONDITIONS, 1992-1993 - IMPLICATIONS FOR ANCHOVY

Samples from the southern California sector of the California Current System were examined to test for changes in abundance, reproduction, r ecruitment and naupliar survival of the planktonic copepod, Calanus pa cificus, coincident: with the 1993 Californian EI Nino, relative to 19 92 (also EI Nino conditions) and to 1989-1991 (defined as 'normal'). I n 1993, as in 1992, females were rare in both winter and spring, but p er capita reproduction was less, food limitation was greater and bioma ss of chlorophyll was reduced only in winter. Recruitment was more var iable than was naupliar survival. Recruitment increased in both El Nin o springs, but survival of older naupliar stages decreased. The mesosc ale distributions of larval anchovy, relative to eggs and nauplii of C alanus, did not result in efficient use of the reduced supply of this source of food, and the abundance of larval anchovy did not cause meas urable variation in the survival of naupliar Calanus.