Morpho-pathological changes in fish species in Surgut urban water bodies

The paper contains preliminary results of a study of morphological and pathological changes in fish species inhabiting Surgut urban water bodies exposed to anthropogenic impact. The city of Surgut is located in the Middle Ob region and has various types of water bodies. In order to assess the state of fish population and fish organisms, the researchers held a visual inspection and an anatomopathological analysis in the course of their morpho-pathological studies. The studies revealed less than 3% of pathology occurance among fish organisms. The external changes included smoothened skin pattern (river perch, pike), spots on eyes (roach), cysts on gills, fin deformities (river perch). The inner changes included local liver congestion (northern pike), cysts in the liver (river perch, pike), extra fluid in the abdominal cavity (singular fishes). The visual inspection of fish revealed fish injuries such as damages to the subcutaneous tissues and muscles (river perch), oral cavity lacerations (nerfling) caused by fishing tackle, contact with prey fish and boats. The fish with morphological and pathological changes included perch, common pike, roach, and nerfling. In general, the occurrence of morphological and pathological disorders identified among fish population in the urban part of the Ob River is less than 3%.