Changes in acanthocephalan infection of the Antarctic fish Notothenia coriiceps in Admiralty Bay, King George Island, over 29 years

Abstract

A comparison between the levels of infection with Acanthocephala of the fish Notothenia coriiceps in Admiralty Bay (South Shetland Islands, Antarctic) in 1978/79 and 2007/08 is presented. The same eight acanthocephalan species, three echinorhynchids ma− turing in fish, Aspersentis megarhynchus (dominant species), Metacanthocephalus john− stoni (subdominant species) and M. dalmori (common species), and five polymorphids ma− turing in mammals and birds, Corynosoma hamanni, C. pseudohamanni (both co−dominant species), C. arctocephali and C. bullosum (both common species), and C. shackletoni (rare species), were found. Echinorhynchids were more numerous in 2007/08 (mean abundance 46.54 versus 35.35 in 1978/79), whereas polymorphids more numerous in 1978/79 (mean abundance 74.35 versus 36.40 in 2007/08). The overall results therefore demonstrated that echinorhynchids were more numerous than polymorphids in 2007/08 and the reverse was true in 1978/79. This situation is dependent mainly upon the decreased infections with C. hamanni, C. pseudohamanni and C. bullosum, and to a lesser degree upon the increasing of infections with M. johnstoni. The decrease of the three Corynosoma spp. is possibly associ− ated with the decreasing of populations of final hosts, seals, on the shore of Admiralty Bay in the vicinity of Arctowski Station.