Food limitation of egg production by a marine, planktonic copepod in the sea off southern California1

Publisher Website
Google Scholar
Abstract
The in situ rate of egg production (B) and female size of Paracalanus parvus, a particle‐grazing copepod, water temperature, and the concentrations of chlorophyll a and particulate nitrogen were measured in 31 collections from the euphotic zone of the sea off southern California. B was correlated positively with chlorophyll a and female size and negatively with temperature. A multiple regression of log B on chlorophyll a, particulate nitrogen, female size, and temperature accounts for 44% of the variation in log B.B was predicted best by an empirical function of food concentration when the food available in nature was considered to be phytoplankton rather than of all types of particulate matter >5 µ.An index of immediate food limitation was derived from laboratory data as a function of food concentration. When applied to extensive measurements of chlorophyll a in the euphotic zone, this index indicates that Paracalanus was often food limited and that food limitation increased along an onshore‐offshore transect. Paracalanus was rarely food limited in Santa Monica Bay.