Background: Calanus finmarchicus, Pseudocalanus moultoni, P. newmani, and Oithona similis

•Calanus is a more opportunistic, highly fecund, broadcast spawner •Pseudocalanus and Oithona carry their eggs in egg sacs (an adaptation thought to reduce egg mortality), and have lower maximum egg production rates •C. finmarchicus and Pseudocalanus exhibit different depth preferences and different susceptibilities to food limitation and predation •Also appear to have different source regions, although this is poorly understood