Infestation of Atlantic chaetognaths with helminths and ciliates

Abstract

The parasite fauna of chaetognaths was investigated at 3 locations: (i) Patagonian Shelf, (ii) 'Great Meteor Bank', (iii) upwelling region off north-west Africa. On the Patagonian Shelf, 4 out of 3,000 chaetognaths (0.16%) were infested by Contracaecum-type larvae, 1 chaetognath harboured an Ectenurus sp. metacercaria. On the 'Great Meteor Bank', 18 out of 8,600 chaetognaths (0.2196) were infested by Cercaria owreae, Ectenurus lepidus, hemiuroid metacercariae or ciliates in April, whereas only 1 E. lepidus metacercaria was found in 4,400 chaetognaths (0.02%) in July. In the north-west African upwelling-region, 640 out of 20,000 chaetognaths (3.2%) were infested mainly by metacer-cariae of E. lepidus and by hemiuroid metacercariae, larval cestodes or ciliates. The distribution of E. lepidus in this area is outlined. The lengths of E. lepidusmetacercariae from north-west African waters increase significantly with distance from the coast. E. lepidus metacercariae were found predominantly in the tail coelom of the chaetognaths.