Influence of Age-Specific Mortality on the Life History Traits of Two Estuarine Copepods

Abstract

Life history traits - including day of first reproduction, lifetime reproductive output, and total lifespan - were determined in the laboratory for 2 estuarine copepods: Scottolana canadensis (Willey) and Oithona colcarva Bowman. The day of first reproduction was earlier for O. colcarva than for S. canadensis , but the latter had a much longer reproductive lifespan and a greater reproductive output in terms of nauplii produced per female. The copepods exhibited intrinsic rates of increase ranging from 0.01-0.19 d super(-1) for O. colcarva (15 degree -25 degree C) and 0.05-0.15 d super(-1) for S. canadensis (20 degree -25 degree C). A comparison of life history traits of S. canadensis and O. colcarva with the copepod Acartia tonsa Dana revealed differences which may reflect variation in age-specific patterns in mortality of the field populations.