The helminth fauna and host–parasite relations of squids Sthenoteuthis oualaniensis (Lesson) (Cephalopoda, Ommastrephidae) in the Indian Ocean and the Red Sea.

Nine species of helminths, including two species of trematodes, three ofcestodes, two of nematodes, and one species of acanthocephalans, were found hi the squid, Sthenoteuthis oualaniensis, from the Indian Ocean and the Red Sea. According to the incidence of infection and the degree of density of the parasite·host relationships, aU of the helminths were distributed into three groups: Main, secondary, and accidental helminths [parasltesl. The age and geographic changes of the helminth fauna ofS. oualaniensi. are presented. The significance ofS. oualan· iensis in the life cycle of helminths is discussed. The helminth fauna of the squids S. oualaniensis and S. pteropus from the Atlantic Ocean is compared. The principle resemblance of the helminth fauna of these species of squids is revealed. The possible reasons for the reduced diversity of species of helminths of S. oualaniensis are