INFLUENCE OF TEMPERATURE REGIME ON EMBRYOGENESIS IN CYPRINIDAE
Temperature is one of essential factors which significantly affect fish ontogenesis and determine roe and embryos survival, viability, morphogenesis, growth of larvae and further growth of fish. Females and males, sexual products, multiple-aged youth of silver carp, bighead carp and grass carp. In the series tests on grass carp incubation at different temperatures there was obtained information on a sure progress concerning sexual proportion in favor of males (94 ± 2.37%) at high temperature, in favor of females (78 ± 4.14%) at low temperature. Temperatures of 17 and 30оС are considered lethal or proximate limits. 22.2-25.5оС is found the most favorable temperature for incubation grass carp roe. The temperature for maximal survival of grass carp larvae ranges within 24-32оС. When the temperature is lower (20оС) or higher (34-35оС) larvae viability descends quickly. The most favorable temperature for grass carp prolarvae and larvae maturing is 30-32оС. The fish which were kept at a temperature of 32оС at early stages of postembryogenesis showed maximal weight and linear growth and viability. The fingerling which matured as larvae at the temperature of 28 and 32оС had a little lower indicators. Further indicators were even lower at 24 and 36оС, the worst indicators were found at 20оС.