MEPS 440:105-114 (2011)  -  DOI: https://doi.org/10.3354/meps09342

ABSTRACT: Organisms have evolved to optimally align the timing of diapause with the seasonality of environmental conditions in order to maximize their fitness. Observations from the Northwest Atlantic suggest that Calanus finmarchicus diapause initiation date varies significantly by geographic location, inconsistent with patterns of seasonal changes of any single environmental factor such as photoperiod, sea surface temperature, or food availability. In the present study, a life history-based model was used to reconcile the apparent inconsistency. The model results suggest that (1) the induction of diapause involves multiple environmental factors as a result of fitness maximization, and (2) in addition to temperature and food condition, predation pressure is another key factor that could affect diapause initiation process. It is further suggested that phenotypic plasticity is likely to be the major source of variation in the timing of diapause initiation for C. finmarchicus.

KEY WORDS: Calanus finmarchicus · Diapause · Life history · Fitness