PARASITE COMMUNITIES OF ABRAMIS BRAMA AND ACCUMULATION OF SOME POLLUTANS FROM DANUBE RIVER, NORTHWESTERN BULGARIA.

In 2019, 16 specimens of freshwater bream, Abramis brama (Linnaeus, 1758) from the Danube River (805-810 river km), Vidin region, northwestern Bulgaria were collected. The fish were examined for the presence of parasites and content of copper (Cu), cadmium (Cd) and arsenic (As). The ecoparasitological examination revealed five species of parasites: Asymphylodora imitans (Mühling, 1898); Nicolla skrjabini (Ivanitzky, 1928); Posthodiplostomum cuticola (von Nordmann, 1832); Caryophyllaeides fennica (Schneider, 1902) and Pomphorhynchus laevis (Müller, 1776). The investigated section of the river is a new habitat for A. imitans, P. cuticola and C. fennica. A. imitans is a core species (P%=56.25) in the parasite community of A. brama. In tissues and organs of freshwater bream, the highest levels of all three elements were detected in the liver samples (C_Cu=11.43±5.92 mg.kg^-1 ; C_As=4.31±1.53 mg.kg^-1 and C_Cd=0.23±0.14 mg.kg^-1 ), followed by those in skin and muscles. In liver samples, the levels of the elements decreased in the order: Cu>As>Cd, and in skin and muscle samples, they decreased in the order: As>Cu>Cd. The study provides new data on parasites and parasite communities of freshwater bream from the Danube River, Vidin region, as well as for the content of some heavy metals/metalloids in water, sediments and A. brama. [ABSTRACT FROM AUTHOR]