The feeding condition of Calanus pacificus and other zooplankton in relation to phytoplankton pigments in the California Current

Abstract

Calanus pacificus copepodite V stages were taken from 40 stations in the California Current between Los Angeles and San Francisco in April 1984. Wax ester and triglyceride contents of the copepods were determined as indices of their feeding condition. The regions with high Chl a concentrations had copepods with high lipid contents and dry weights, while the low Chl a region farther offshore had copepods with low lipid levels and dry weights. The Southern California Bight generally had intermediate to low Chl a concentrations, which was also reflected in the copepod parameters.Wax ester content and dry weight of Calanus had higher correlations with primary production (r = 0.86; r = 0.89) than with total integrated Chl a (r = 0.65; r = 0.55). Lipid content of field‐caught copepods was much higher than that of laboratory animals reared at a high concentration of food.Additional species were taken in a subarea south of Point Conception. Lipid content of the grazing copepod Rhincalanus nasutus was also significantly related to pigment concentration and showed good concordance with Calanus. Lipid contents of furcilia stages of Euphausia pacifica and chaetognaths, on the other hand, were not significantly correlated with the pigment concentrations or the lipid contents and dry weights of the copepods.