ANISAKID NEMATODES IN THE COMMON SEAL (PHOCA-VITULINA L.) IN ICELANDIC WATERS

The occurrence of anisakid nematodes in the common seal in Icelandic w aters was studied by investigating digestive tracts of 95 seals during 1979-82. The most abundant adult species was Pseudoterranova decipien s. Contracaecum osculatum, and Phocascaris cystophorae were less frequ ent. In addition larvae of Anisakis simplex were common. The prevalenc e and abundance of these nematode species did not differ significantly between seasons. The prevalence and abundance of P. decipiens showed marked geographic variations, with higher frequency and higher numbers in common seals from the west and northwestern coast, than from other coastal areas of Iceland. Male common seals had higher abundance of P . decipiens than females, and the number of P. decipiens worms was pos itively correlated with age in male seals. The sex ratios of P. decipi ens and C. osculatum worms were close to 1:1, but the sex ratio of P. cystophorae was close to 1.1.7, in favour of females. A significant po sitive correlation was observed between numbers of P. decipiens and C. osculatum.