Health status of rudd (Scardinius erythrophthalmus hesperidicus H.) in Lake Vrana on the Island of Cres, Croatia |
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Authors: | N. Topi Popovi ,M. Hacmanjek,& E. Teskered i |
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Affiliation: | Ruder BoškovićInstitute, Center for Marine Research, Laboratory for Aquaculture, Zagreb, Croatia |
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Abstract: | The health status of rudd ( Scardinius erythrophthalmus hesperidicus H.) in Lake Vrana, the largest Croatian karstic lake, was evaluated. Studies comprising parasitological, haematological and bacteriological surveys were conducted over a 2-year period. Parasitological examination revealed a light infestation of 27% of the examined fish, mostly Dactylogyrus and Ichthyophthirius species. Haematological studies showed that haematocrit values were lower than the physiological limit. A haematocrit coefficient of correlation in all research periods was higher than 15%, indicating that the majority of fish in the study were susceptible to the development of bacterial and other diseases. Indeed, a diverse array of bacteria were isolated from rudd, mainly Flavobacterium spp. and Aeromonas spp., but also some specific fish pathogens, notably Pasteurella piscicida, Yersinia ruckeri , and Edwardsiella ictaluri , were identified. Under stress conditions, detected bacterial species can give rise to disease outbreaks. |
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