Fróðskaparrit - 01.01.1992, Side 15

THEINTERNATIONAL RESEARCH .. .
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in marine mammals off the Faroe Islands. Eco-
toxicology and Environmental Safety 24: 95-101.
Parasite fauna
16 species of helminths and three species of
crustaceans were identified. The most
prevalent species were the nematodes
Anisakis simplex and Stenurus globicepha-
lae, and this can be paralleled with the
abundance of larval stages in some fish and
squids found in Faroese waters, especially
in Todarodes sagittatus. Prevalence of all
species tended to be cumulative with age.
Nevertheless, the abundance of some para-
sites showed a decline in older animals, e.g.
the nematode A. simplex and the trematode
Pholeter gastrophilus. This may indicate a
higher mortality rate of the most severely
infested animals. Furthermore other
species are also considered as having sig-
nificant pathological effects and parasitism
could then be a non negligible factor of
mortality.
Prevalence, abundance and spatial distri-
bution of the whale-louse Isocyamus del-
phini on sexually mature males was signif-
icantly higher and different from those of
the remainder. Behavioural factors seemed
to account for these differences, with
mature males exhibiting additional whale-
louse shelters such as tooth-rake scars and
severe wounds which probably result from
sexual fighting.
Qualitative and quantitative differences
in the parasite fauna composition of pilot
whales were found between the Faroe
Islands, the Atlantic French coasts and
Spanish Mediterranean coasts, as well as
Newfoundland (Cowan, 1966; 1967).
Eight schools were examined with
respect to the abundance of the helminth
species (220787;240787;020887; 190887;
180987; 081087; 201087; 100689). The
abundance of the acanthocephalean
Bolbosoma capitatum was significantly
higher in 3 schools (Leynar, 220787;
240787; Miðvágur 020887) and signifi-
cantly lower in one school (Tórshavn,
081087). As well, the latter school showed
a significantly higher abundance of the
trematode species Hadwenius delamurei
and H. subtilus. This supports the idea of
several sympatric populations in Faroese
waters, but might also be partly due to sea-
sonal or long-term variations of the abun-
dance of infective stages. Differences
between schools could also be observed in
the population structure of the nematode
Anisakis simplex (Desportes et al., 1993).
Future work will be devoted to studying
the intestinal helminth communities, their
structure and the mechanisms determining
their appearance (Balbuena, pers. comm.).
Balbuena, J.A. 1991. Estudio taxonómico y ecológico de la
parasitofauna del calderon comun, Globicephala melas
(Traill, 1809), en las aguas de Europa. Thesis Doctoral.
Universitat de Valencia, Facultad de Ciencias
Biológicas. 1-305.
Balbuena, J.A. and Raga, J.A. 1991. Ecology and host rela-
tionships of the whale-louse tsocyamus delphini
(Amphipoda: Cyamidae) parasitising long-finned pilot
whales (Globicephala melas) off the Faroe Islands
(Northeast Atlantic). Can. J. Zool. 69: 141-145.
Balbuena, J.A., Raga, J.A. and Abril, E. 1989.
Redescription of Odhneriella subtila (Skrjabin, 1959)
(Digenea: Campulidae) from the intestine of
Globicephala melaena (Traill, 1809) (Cetacea:
Delphinidae) off the Faroe Islands (North-East
Atlantic). Systematic Parasitology 14: 31-36.
Raga, J.A. and Balbuena, J.A. 1989. Parasites of the long-
finned pilot whale, Globicephala melas (Traill,1809), in
European waters. Paper SC/41/SM28 presented to the