Occurrence of Contracaecum clavatum Rudolphi in angler-fish ( Lophius piscatorius L.) from the North Irish Sea

Abstract

Infestation of angler-fish Lophius piscatorius L. with the nematode Contracaecum clavatum Rudolphi was investigated. Of 1621 angler-fish examined from the north Irish Sea, 45.4% harboured Contracaecum, the stomach being the most frequent site of infection. Seasonal fluctuations in prevalence and abundance of Contracaecum were observed, infestation peaking during the winter period, coinciding with maximum feeding activity and dominance of known transport hosts in the diet. Infestation initially increased with age of host, 2- and 3-year-old Lophius being most heavily infected. A decline among older fish is probably related to termination of infection rather than parasite-induced mortality. This is supported by a shift in diet among older angler-fish away from prey which harbour Contracaecum infections.