Moulting and mortality rates of copepods related to age within stage: experimental results

Abstract

Patterns of copepod mortality and moulting related to age within stage, described by a mathematical model of population dynamics, were tested experimentally on Centropages typicus. Probabilities of moulting and dying depended on age within stage. In all copepodite stages, the distribution of durations in relation to age within stage was asymmetrical around a mode. A minimum mortality rate (0.01 to 0.02 d-1) was present before the mode of the duration distribution. Beyond the mode, mortality increased up to a maximum of 0.1 for individuals which stayed in a stage twice as long as normal. The variable development of copepods bred from a synchronous cohort seems to be determined by the diverse physiological conditions displayed by different members of the same population. -from Authors