抽象的

Advancement in the Spawning Time of Goldfish Carassius auratus under Various Tmperature and Photoperiod Shifts

Bhavna Upadhyay and Amita Sarkar

Our aim of the present study is to manipulate the spawning time of goldfish Carassius auratus by using different Photo period and Temperature regimes so that there fry will be available all the year around. 4 photo regimes were used representing 3 treatments and control. The first photo regime (control) were subjected to the natural light at room temperature. The second aquaria treatment 1 were kept under 17L/7D at 240C. The third aquaria representing treatment 2 were subjected to 13L/11D Photo period at 240C. Photo period of last aquaria was adjusted 15L/9D at 240C. The first sample was taken after 30 days from the beginning of the experiment. The second one was after 50 days from the beginning of the experiment. The third was carried out after 70 days from the start of the experiment, and last one was after 90 days respectively.After 30 days from the start of the experiment, 17L/7D at 240 Creached the ripe stage earlier than the other ones (40 days earlier than the control group).After 50 days from the beginning of the experiment 15L/9Dat 240C followed treatment 1. The spawning time of 15L/9Dat 240C started 20 days earlier than the control. After,70 days control was the third to reached the ripe stage. The last treatment that reached egg-ripening stage was the 13L/11D at 240C after 90 days fromthe beginning fromthe experiment. The spawning time of second treatment also extend to overlap with that of the control later 20 days.Accordingly, there was an artificial spawning time (additional 40 days) that prolonged the natural spawning season and extended the availability of Carassius fry for a longer period Weight gain, Feed conversion ratio and Gonadosomatic index, were also discussed.