A COMPARISON OF ZOOPLANKTON SAMPLING METHODS IN THE CALCOFI TIME-SERIES

We review changes in macrozooplankton sampling methods over the course of the CalCOFI time series (1949-present). After 1951, two major chan ges occurred: sampling depths were extended from 140 m to 210 m in 196 9, and the 1.0-m-diameter bridled ring net was replaced with a 0.71-m- diameter bridleless bongo net in late 1977. We compare how these two c hanges affected the efficiency of collecting zooplankton biomass. We p rovide conversion factors between these sampling methods, supplemented by a description of the nonlinear relationship between wet and dry zo oplankton biomass in the California Current system.