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