Biodiversity, Bioindication and Helminth communities of Abramis brama (Linnaeus, 1758) from the Danube River and Lake Srebarna, Bulgaria

Abstract

Biomonitoring from water of the River Danube and Srebarna Lake was performed using freshwater fish and their parasites and parasite communities as bioindicators. During 2013, 78 specimens of freshwater bream (Abramis brama (L., 1758) were examined with standard techniques for parasites. Three species of parasites (Gyrodactylus elegans Nordmann, 1832, Diplozoon paradoxum Nordmann, 1832 and Pomphorhynchus tereticollis (Rudilphi, 1809)) were fixed. The analysis of the dominant structure of the found taxa was presented to the level of the component communities. New parasite and host records were determined. All fixed parasite species are core for the parasite communities of examined fish. Concentration of heavy metals (Pb, Zn, Cu) in fish (muscle, liver, intestine and bones), endohelminth species Pomphorhynchus tereticollis as bioindicators and bottom sediments were analyzed. Bioindicator significance of parasite species was studied. For an ecological evaluation of the situation of the analyzed freshwater ecosystems, principal biotic indices were fixed