Anatomical and functional effects of the parasitic copepod Lernaeocera branchialis (L.) on Pollachius pollachius (L.) (Pisces: Gadidae)

Abstract

The paper describes aquarium and laboratory observations of the influence of the copepod, Lernaeocera branchialis, on tissue changes in three species of gadid fishes taken from Gullmar Fjord, on the west coast of Sweden. The most extensive infestation by the parasite was noted in Merlangius merlangus (8.7%), in Gadus morhua (3.0%) and Pollachius pollachius (2.2%). The most extensive deformation of tissue occurred, however, in P. pollachius. This included a deformed left gill cover, perforation of the ventral artery and possibly deformation of certain bones of the viscerocranium. The changes in M. merlangus and G. morhua did not differ from those (hitherto known from the literature) reported previously.