Jellyfish outbreaks in the Bay of Calvi (Corsica)

The interannual variations of the Schyphozoan jellyfish Pelagia noctiluca is estimated by weekly measurements in the Bay of Calvi (Corsica) from 2003. The mean annual abundance reaches a dramatic maximum in 2006.
The medusae appear by migration of active swarms on the shelf and at the external limit of the Bay. Degraded individuals drift as passive swarms, throughout inner side of the Bay and embayment.