Microscopic photoplethysmography-based evaluation of cardiotoxicity in whitefish larvae induced by acute exposure to cadmium and phenol.

Toxic environmental pollutants pose a health risk for both humans and animals. Accumulation of industrial contaminants in freshwater fish may become a significant threat to biodiversity. Comprehensive monitoring of the impact of environmental stressors on fish functional systems is important and use of non-invasive tools that can detect the presence of these toxicants in vivo is desirable. The blood circulatory system, by virtue of its sensitivity to the external stimuli, could be an informative indicator of chemical exposure. In this study, microscopic photoplethysmography-based approach was used to investigate the cardiac activity in broad whitefish larvae (Coregonus nasus) under acute exposure to cadmium and phenol. We identified contamination-induced abnormalities in the rhythms of the ventricle and atrium. Our results allow introducing additional endpoints to evaluate the cardiac dysfunction in fish larvae and contribute to the non-invasive evaluation of the toxic effects of industrial pollutants on bioaccumulation and aquatic life.

Biological responses of whitefish (Coregonus lavaretus L.) to reduced toxic impact: Metal accumulation, haematological, immunological, and histopathological alterations.

Bioaccumulation of the main pollutants in the organs of whitefish, as well as their haematological parameters, were examined dynamically over a 40-year period in historically contaminated Lake Imandra. A quantitative histological analysis was performed to assess the physiological state of whitefish and histopathologies of organs, as well as their physiological and biochemical functions in the current period of toxic load decline. Biological reactions of whitefish from the historically contaminated area have been greatly modified in contrast to those of whitefish from the never contaminated area of the lake, and this shift persisted even after approximately 20 years of toxic load decline. First, high antioxidant status supports the body's systems, smoothing over the negative consequences of metal toxicity, phagocytosis and inflammatory reactions. Moreover, the defence mechanism of whitefish from the historically contaminated area actively uses the oxidative systems of nonspecific immunity. Second, the adaptive strategy is aimed at improving gas exchange without compensatory proliferation of gill structure, which increases their functional surface and reduces the distance to the bloodstream, as well as increasing haemoglobin in maturing erythrocytes. Third, the higher efficiency of endo- and phagocytosis was confirmed by detecting increased monocytes and macrophages in the peripheral blood and decreased melano-macrophage centres in the fish kidney. Elevated accumulation of Fe, Cu, and Se may serve a sign of liver pathology, while elevated accumulation of Zn and Co already indicates kidney pathology, which is confirmed by histopathological alterations.

Data on length-weight and length-length relationships, mean condition factor, and gonadosomatic index of Rutilus rutilus and Perca fluviatilis from the Ob River basin, Western Siberia.

Raw data were obtained from 250 specimens of roach Rutilus rutilus and 274 specimens of perch Perca fluviatilis at 15 sampling sites located from North to South Taiga. Fish sampling was performed using gill-nets with 22 and 28 mm mesh. Total and eviscerated weights, total and standard lengths, fish sex, gonad weight and maturity stage were recorded. Linear regression analysis of log-transformed total weight and total length values was performed. Regression slope and intercept were used to obtain length-weight relationships and mean condition factor values. Length-length relationships were calculated by the linear regression between the total and standard lengths. Gonadosomatic index was determined using the gonad weight and the total weight of fish. The data are useful for establishing biomass, fish growth patterns, relative condition of individuals within a sample or across populations.