Feeding and respiration in the New Zealand copepod Calamoecia lucasi brady

Summary

Filtering rates of the various growth stages of Calamoecia lucasi were determined in cultures of yeast labelled with ¹⁴C, and the effects of food concentrations and temperature on filtering and feeding rates examined. Filtering rates decreased with increasing food concentration, and above a limiting value of 0.8×10⁴ cells·ml^-1 feeding rates were maximal and did not increase further. Filtering rates increased with increasing temperature up to 20°C, and from nauplius to adult, although weight specific feeding rates were highest in CII. Assimilation efficiencies of the adults averaged 65%. The effect of temperature on the rate of oxygen consumption of C. lucasi, Boeckella delicata and B. symmetrica was measured using the micro-Winkler technique, and the regression relationship between log oxygen uptake, temperature and log weight calculated for the three species. Using these data a preliminary energy budget was calculated for C. lucasi. The balance between food intake and respiratory output was positive in all stages except the nauplius, and was greatest in CII–IV. This concurs with information from field studies of C. lucasi in which daily P/B ratios were greatest in these stages also.