INMPACT OF PHOTOPERIOD DURATION ON THE GROWTH OF RAINBOW TROUT (ONCORHYNHUS MYKIS WALBAUM, 1792) ERTAIN SPECIMENS OF

Photoperiod duration was proven to be inversely proportional to fry body growth, and variation coefficient (Cv) of fry body mass was directly proportional to fry aggressiveness. Significant negative correlation between the number of aggressive reactions and fry body mass was discovered. Direct relationship between Cv and general fry biomass was statistically proven. Thus, photoperiod duration indirectly affects growth of rainbow trout (Oncorhynhus mykis Walbaum, 1792)fry. Daylight time duration affects the number of aggressive reactions, which in turn directly inhibit fry growth.