HELMINTH COMMUNITIES AND ECOLOGICAL APPRAISAL FOR THE CONDITION OF THE VELEKA RIVER, BLACK SEA REGION, BULGARIA

Biodiversity and ecological particularities of the parasite communities of the Black Sea Roach (Rutilus frisii (Nordmann, 1840)) and (Alburnus chalcoides (Güldenstädt, 1772)) from the Veleka River (Black Sea Region) were studied during 2013. 59 specimens of R. frisii and 97 specimens of A. chalcoides were examined with standard techniques for parasites and heavy metal contamination. The purpose of this research is to represent new data for the biodiversity, prevalence, intensity and mean intensity, mean abundance of parasite communities of both fish host species. Basic physicochemical indicators in fish, some endohelminth species as bioindicators and bottom sediments were analyzed. The obtained results for the parasite communities of R. frisii and A. chalcoides correspond and are in close connection with dependence of the biology and ecology of the determined species of helminthes and the place of the intermediate hosts as bioindicators for the status of the studied natural freshwater ecosystems. The results may be applied in the various monitoring systems for assessment and forecast of the Veleka River condition.