TEMPORAL VARIATIONS IN THE INFECTION OF A POPULATION OF CLYPEOMORUS BIFASCIATA (GASTROPODA, PROSOBRANCHIA) BY A DIGENEAN MICROPHALLID LARVAIN KUWAIT BAY

The prosobranch snail Clypeomorus bifasciata in Kuwait Bay was examine d for digenean infections over a one year period during 1994/1995. A t otal of 1500 snails was examined and 567 (37.8%) were found to harbour nine digenean species. The prevalence of a microphallid species was 3 3.9% while each of the others occurred in less than 1.2% of the snails . The prevalence of infection increased with shell size. Multiple infe ctions were observed in only five of the infected snails and the micro phallid was involved in all of them. Snails were infected with the mic rophallid throughout the year and there appeared to be two peaks in th e proportion of infected snails shedding cercariae, a winter peak from November to January and a summer peak from June to August. The crab X antho exaratus collected from snail sampling sites was heavily parasit ized by microphalIid metacercariae of the genera Longiductotrema and M icrophallus. This is the first report on microphallid metacercariae in crabs in the Arabian Gulf region.