|Endoparasitic helminths of the harbour seal, Phoca vitulina, in the Netherlands|
Borgsteede, F.H.M.; Bus, H.G.J.; Verplanke, J.A.W.; van der Burg, W.P.J. (1991). Endoparasitic helminths of the harbour seal, Phoca vitulina, in the Netherlands. Neth. J. Sea Res. 28(3): 247-250
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579, more
|Authors|| || Top |
- Borgsteede, F.H.M.
- Bus, H.G.J.
- Verplanke, J.A.W.
- van der Burg, W.P.J.
The endoparasitic helminth fauna of harbour seals which had died during the epidemic of the phocine distemper virus in 1988 was studied. Lungs, heart and gastrointestinal tracts of 94 animals collected along the Dutch coast were available for investigation. The following parasites and infection percentages were found: Nematoda: Dipetalonema spirocauda (24.5%), Otostrongylus circumlitus (6.4%), Parafilaroides gymnurus (24.5%), Ascaridoidea spec. (58.5%); Trematoda: Phagicola septentrionalis (66.0%), Cryptocotyle lingua (74.5%); Cestoda: Diphyllobothrium spec. (8.5%); Acanthocephala: Corynosoma strumosum (70.2%). The presence of worm species was not evenly distributed over the age classes. Seals younger than one year harboured fewer parasites. The highest percentages were found in 1 to 2 year old seals. The number of worms per seal varied greatly. The highest burden for ascarids was 253, for P. septentrionalis 123 000, for C. lingua 112 000 and for C. strumosum 251. A comparison of the present results with those described in the literature shows that in Dutch seals the same species were present and that numbers of worms were not higher than before the 1988 mass mortality. It is therefore concluded that helminth parasites did not cause the mass mortality.