The helminth fauna of the common seal (Phoca vitulina vitulina, Linné, 1758) from the Wadden Sea in Lower Saxony. Part 1: Trematodes, cestodes and acanthocephala.

Between August 1988 and January 1989 110 common seals found dead along the coast of Lower Saxony were investigated for the occurrence of trematodes, cestodes and acanthocephala. Two fluke species, Cryptocotyle lingua Creplin, 1825 and Phagicola septentrionalis Van Den Broek, 1967, two tapeworm species Diphyllobothrium cordatum Leuckart, 1863 and Diphyllobothrium elegans Krabbe, 1865, and the acanthocephala species Corynosoma strumosum Rudolphi, 1802 were found. Phagicola septentrionalis and the cestodes were always found together with Cryptocotyle lingua. The prevalence of Phagicola septentrionalis, the diphyllobothriids and the acanthocephala increased with increasing age of the pinniped host. The worm counts of all species appeared to increase with increasing age of the host. The adult male seals were more often infested with Phagicola septentrionalis and cestodes than the female adults and the younger pinnipeds. There was no correlation between blubber thickness of the seals and parasitic infection. The prevalence of the diphyllobothriids and the intensity of the infection with acanthocephala were higher in seals found in the eastern part of the Wadden Sea.