Bioindication using fish and its role in an integrated assessment of the condition of coastal ecosystems: a review

Coastal ecosystems located near cities, industrial and agricultural facilities are under significant anthropogenic influence. The complexity of modern anthropogenic impact on coastal ecosystems does not always make it possible to determine the quantitative content of all pollutants. The traditional methods used make it possible to assess physical and chemical indicators, but they do not provide a comprehensive assessment of the impact on the biological system. The use of bioindication methods that reflect the response of aquatic organisms to the complex influence of the environment is extremely relevant. Fish are a large group of vertebrates and inhabit a wide range of ecosystems where they are exposed to many different aquatic pollutants. In bioindication studies, both morphophysiological and biochemical indicators of fish are widely used. The use of morphophysiological indicators makes it possible to assess the impact of environmental factors on the organism, as well as the specifics of its adaptation to environmental changes. Due to the development of biochemistry and molecular biology, such new techniques appear that make it possible to determine the impact of an environmental factor at those stages when changes occur at the cellular, membrane and molecular levels, and do it before this impact leads to irreversible pathological processes. The use of bioindication methods, that reflect the reaction of biota to the entire complex of negative environmental influences, is a relevant and promising method. The review examines in detail modern bioindication methods based on determining the morphophysiological and biochemical parameters of fish, and also assesses the role of the bioindicator approach in a comprehensive assessment of the state of the environment.