During the seal epidemic in 1988 and the beginning of 1989, 115 common seals found dead on the shores of the Wadden Sea of Lower Saxony were investigated for the presence of nematodes. The lungworm Otostrongylus circumlitus RAILLIET 1899 was found in 26.1 % of the seals, the lungworm Parafilaroides gymnurus RAILLIET 1899 in 26.9 % and the heartworrn Dipetalonema spirocauda LEIDY 1858 in 32.2 % of the seals. In the digestive tract, two anisakid species were found, Pseudoterranova decipiens MOZGOVOI 1951 in 87.8 % and Contracaecum osculatum RUDOLPHI 1802 in 10.4 Yo of the seals. Statistical analysis revealed a negative correlation between age of the seals and prevalence and intensity of infestation with the two lungworm species and the heartworms. Adult seals were found not to be infected with Dipetalonema spirocauda and Parafilaroides gymnurus, whereas the prevalence of the two anisakid species increased with increasing age of the seals. Pseudoterranova decipiens was found more often in autumn and winter than in summer. This parasite was more prevalent and had higher worm counts in the eastern part of the Wadden Sea than in the western part. Parafilaroides gymnurus and Dipetalonema spirocauda were found more often in seals with smaller blubber thickness than in well fed seals.

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 acantocephala. Two fluke species, Cryptocotyle lingua CREPLIN, 1825 and Phagicola septentrionalis VAN DEN BROEK, 1967, two tapeworm species Diphyllobothriurn cordatum LEUCKART, 1863 and Diphyllobothriurn elegans KRABBE, 1865, and the acanthocephala species Corynosoma strumosurn 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.