The use of field data to derive population statistics of multivoltine copepods1

The mean duration of each instar of planktonic copepods is obtained from field data only, by using the relation: urn:x-wiley:00243590:media:lno19741940636:lno19741940636-math-0001 where Mn is the mean pulse time of instar n and tn is the duration of that instar. The method is used to calculate population statistics of univoltine populations from European lakes and of a multivoltine population of Skistodiaptomus oregonensis in a 0.5‐ha meromictic lake in southern Ontario. As a check on the method, development times of eggs, first nauplius, and second nauplius were determined in the laboratory and combined with in situ vertical distribution and water temperature data to give an independent estimate of in situ development times of these instars. The two compared favorably. Growth rate of S. oregonensis is not simply a function of temperature.