The occurrence of Caryophyllaeus laticeps in the nase Chondrostoma nasus from Austrian rivers: possible anthropogenic factors.
Between April 2003 and November 2006 a total of 198 nase Chondrostoma nasus (L.) were examined for parasites from seven river sites in Austria. The selected sites showed different levels of anthropogenic alterations in river morphology ranging from pristine areas, with minor anthropogenic alterations, to strongly physically altered rivers. A variety of parasites were recovered from the skin, gills, swimbladder and eyes, with Caryophyllaeus laticeps (Pallas) being identified as the only cestode species occurring in the intestine. This is the first record of this species in nase in Austria. Caryophyllaeus laticeps was confined to the first 20% of the intestine, even in heavily infected hosts. The occurrence of C. laticeps within the fish population seems to be correlated with the degree of anthropogenic changes of the nase's habitat. In rivers with a high degree of ecological integrity or in rivers that are only partially dammed, C. laticeps is either absent in C. nasus or occurs with low prevalence (5.6-20%) and low mean intensity values (1.0-4.0). Where anthropogenic factors have changed the entire river into a reservoir, and fish cannot escape, the prevalence of infection with C. laticeps increases from 46.2 to 78.2% and the mean intensity from 8.8 to 17.2.
Department of Evolutionary Biology, Emerging Focus Molecular Phylogenetics University of Vienna, Althanstrasse 14, 1090 Vienna, Austria. franz.jirsa@univie.ac.at
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D000818:Animals; D001317:Austria; D002589:Cestoda / Q000302:isolation & purification*; D002590:Cestode Infections / Q000175:diagnosis* / Q000209:etiology / Q000635:transmission; D003530:Cyprinidae / Q000469:parasitology; D017753:Ecosystem; D004738:Engineering; D005393:Fish Diseases / Q000209:etiology / Q000469:parasitology*; D006790:Host-Parasite Interactions; D011157:Population Dynamics; D045483:Rivers