Results of comparative analysis of the content of immune complexes and lipids and of the oxidative processes in the muscle tissues of Rapana venosa occurring in various sections of the coastal zone of the Caucasus coast of the Black Sea differing in the degree of anthropogenic load are given in the paper. It has been found that the specimens caught in the sections subjected to intensive anthropogenic load were characterized by a rather high content of the products of lipid peroxidation and immune complexes and by a low antioxidant activity.

The results of the study on several immuno-biochemical parameters of blood serum and liver of Engraulis encrasicholus ponticus (L. 1958) and Sprattus sprattus phalericus (L. 1958), that inhabit the Caucasus coastal waters of the Black Sea with various anthropogenic loads are described. The antimicrobial properties of serum, the content of non-specific immune complexes, in the liver antioxidant activity were studied. It was determined that the ratio of immunodeficient individuals was much higher in samples from the polluted areas than in samples from the clean ones. The fish sampled in areas of high anthropogenic load contained higher contents of products of lipid peroxidation and immune complexes, as well as lower values of antioxidants.

Investigation results are reported on immunobiochemical indices in carassius carassius at a chronic exposure to sub-lethal Zink ions concentrations. In blood serum and liver, the following characteristics were investigated: antimicrobial properties, proportion of immune- deficient animals, content of non specific immune complexes, common lipids level, content of lipids peroxidation products and antioxidant activity. The relation between magnitudes of indices under investigation in fishes and the duration of their presence under experimental conditions is shown.

Исследовано влияние тестостерона на состав лейкоцитов периферической крови и иммунокомпетентных органов стерляди Acipenser ruthenus. В лейкограммах опытных и контрольных рыб после введения соответственно гормона и физиологического раствора зарегистрировано изменение соотношения отдельных типов белых клеток крови. На воздействие гормона рыбы реагируют снижением содержания лимфоцитов и увеличением нейтрофилов и моноцитов. Наибольшие отклонения отмечены в лейкограммах периферической крови, наименьшие – в селезёнке.

Results of the long-term researches on variability of humoral factors of natural immunity of bream (Abramis brama L.) of the Rybinsk reservoir over the fattening period at various biomasses and composition of forage objects are analyzed. Connection of functional characteristics of immunity and macrozoobenthos' abundance and structure is established. Breams, caught over low abundance of the benthic organisms, were characterized by high portion of immune-deficit specimens and moderate values of antimicrobial properties of blood serum.