Interspecies Peculiarities of Some Enzyme Activities in the Gonads of Black Sea Fish.

Significant interspecies differences were established in activities of aminotransferases, alanine aminotransferase (ALT, EC 2.6.1.2) and aspartate aminotransferase (AST, EC 2.6.1.1), and alkaline phosphatase (ALP, EC 3.1.3.1) in the gonads of seven Black Sea fish species during spawning and non-spawning seasons. In most species, ALT and AST activities were higher in the non-spawning phase compared to the spawning one, while ALP activity demonstrated an opposite trend. The peak enzymatic activities were found in the gonads of the whiting, probably due to its spawning in the winter season. No significant differences were revealed between the test parameters in animals of different ecological groups. ALT, AST and ALP activities in fish gonads can be used as convenient and efficient markers to explore both the peculiarities of the gonadogenesis at different stages of the reproductive cycle and the ability of different fish species to adapt to unfavorable environments, including those caused by anthropogenic pollution. [ABSTRACT FROM AUTHOR]