Micro- Zooplankton in the Euphotic Zone at Five Locations Across the California Current

Abstract

Quantitative samples of the plankton which passed 202-μ mesh filter cloth were collected with a pumping system at five locations from the slope waters of the Pacific Ocean off San Diego to across the California Current.A general decrease in the numbers of micro-zooplankton, averaged over the depth of the euphotic zone, was found from the slope waters (310,000/m 3 , Station I) to the site farthest offshore (99,000/m 3 , Station V). At the various sites Protozoa accounted for between 59% and 83% of the total numbers, but only 18–23% of the total micro-zooplankton volume. The calculated volumes of the micro-zooplankton ranged from 22.9 mm 3 /m 3 (Station I) down to 6.3 mm 3 /m 3 (Station V).