EFFECT OF STARVATION ON DEVELOPMENT AND SURVIVORSHIP OF NAUPLIAR CALANUS-PACIFICUS (BRODSKY)

In the marine planktonic copepod, Calanus pacificus (Brodsky), survivo rship and development rate during the remaining naupliar stages were r educed when initial feeding was delayed for similar to 10 h after molt ing into naupliar stage III (NIII). In otherwise well-fed stages NIII- NVI, development and survivorship were reduced after starvation period s >6 h and >14 h, respectively. Molting rate and survivorship were low er in response to transient starvation than in response to constantly low food supplies. Stage NV was the least sensitive to transient starv ation, while stages NIII and NVI were the most susceptible. Molting ra tes were reduced even after abundant food was subsequently provided. T hus, ambient food concentration at the time a population is sampled ma y not be an adequate index of future cohort success. Estimates of fine -scale to micro-scale particle distributions in situ suggest that NIII , the first feeding stage, is the instar most likely to experience sho rt starvation periods if hatching occurs well below phytoplankton-rich strata.