STRUCTURAL INDICES OF POPULATIONS OF MAJOR COMMERICAL FISHES OF THE KREMENCHUK RESERVOIR

According to control gill net catches, major commercial fishes in middle part of the Kremenchuk reservoir are bream, crucian carp, silver bream, roach, and pikeperch. Bream population structure in catches in 2013 was characterized by widening of its modal range that is related to a decrease of middle age groups. Unstable state of the population and high enough mortality index of bream ? 0,74 are first of all related to intensification of fishing effort on these age groups. Structural indices and mortality values of silver bream (0,66), roach (0,60), crucian carp (0,68) in whole correspond to those of balanced populations in conditions of moderate fishing effort. Pikeperch population in catches was represented by 5 age groups only and 71,1 % of its number was represented by age 3 fish. The absence of older age groups at high enough recruitment number also indicates on high fishing effort towards this species.