Digeneans parasitizing intertidal snails that use fish as final hosts on Patagonian coasts, Argentina

CARMEN GILARDONI; ESTEFANÍA BAGNATO; FLORENCIA CREMONTE

Viña del Mar

Simposio; VIII International Symposium of Fish Parasites; 2011

South American Ictioparasitologist Consortium

The goal of this work is to determinate the species of larval digeneans parasitizing the more abundant intertidal snails that use fish as final host on Patagonian coasts, Argentina.Seasonally, we collected 100 individuals of each species of gastropod from July 2008 to August 2010 at 3 sites: Playa Fracasso (42.42ºS, 64ºW) in San José Gulf, Puerto Madryn (42.77°S, 65ºW) in Nuevo Gulf and Puerto Deseado (47.77ºS, 66ºW). The snails were transported to the laboratory, placed in small flasks to get cercarial emission and dissected.Larval stages were identified. Species richness, proportion of digenenean of fish and birds and prevalence for the three sites were calculated. Four from 11 species of parasites foundcorrespond to fish parasites. Only one species was present in the 3 sites: sporocysts and cercariae of Hemiuridae family in the pulmonated snail Siphonaria lessoni. Sporocysts with cercariae and metarcercariae of Diphterostomum sp. (Zoogonidae) were found in Playa Fracasso and Puerto Madryn in Buccinanops globulosus. Two species of Lepocreadidae, with rediae and cercariae were registered in Puerto Deseado in the gastropod Crepidula dilatata and Pareuthria plumbea. The proportion of parasites that finish the life cycle onfish is lower (~30%) regarding to those that finish the life cycle in birds for the 3 sites. Fish species also show lower overall prevelences (6.38%) in comparison with birds species (93.62%). The low prevalences and species richness of fish parasites could be explained because the gastropods are from the intertidal, and in those environments, the life cycles are promoted mainly by sea birds. However, the larvae of fish digeneans in the gastropods are indicating the presence of coastal fish feeding in the intertidal zones.