Feeding and respiration in the New Zealand copepod Calamoecia lucasi brady

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.