Abstract
Diel vertical distribution patterns of the copepodite and adult stages of Calanoides carinatus were analysed using a 10-day time series of observations under contrasting upwelling conditions at an Anchor Station in St Helena Bay, South Africa. The diel vertical migratory behaviour of C. carinatus is probably controlled by both exogenous and endogenous factors. Changes in the food assemblage associated with upwelling significantly modified the vertical distribution and migration of C. carinatus from nonmigratory behaviour under nonsatiating feeding conditions (microflagellates) to marked diel vertical migrations in an upwelling-induced, improved feeding environment (small diatoms). Intrinsic factors such as age, sex and state of ovary maturity also play an important role in the vertical habitat partitioning of C. carinatus in St Helena Bay. Such differential migratory strategies are believed to be adaptations for optimal food utilisation and population maintenance through age-specific depth partitioning. Other adaptive advantages are maximization of reproductive success by copulating at depth at night, and rapid egg development and maximal survival of the first-feeding nauplii by spawning near the surface.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call