Recruitment variability of chokka squid (Loligo vulgaris reynaudii) — role of currents on the Agulhas Bank (South Africa) in paralarvae distribution and food abundance

It is believed that annual variability in chokka squid catches may be linked to recruitment success. For the oceanic Illex species, recruitment variability has been shown to be strongly related to changes in Western Boundary Currents (WBCs) as these play a major role in the life cycle. This paper investigates the role of currents in the early life cycle of chokka squid. A synthesis of currents on the Agulhas Bank is undertaken within the context of paralarvae food distribution and availability. Flow patterns are shown to be less defined and more complex than WBCs. Copepods are widely available for the paralarvae on the shelf, which suggests that starvation is not a limiting factor in chokka squid recruitment success. Instead of playing a positive role in the early life history of the chokka squid, currents appear to present a threat to the survival of paralarvae by removal from the shelf ecosystem. This can influence recruitment.