Finfish Breeding and Hatchery Management

Unit 3 - Breeding of major carps

3.1.4. Factors responsible for breeding of fish in bundhs

• Spawning may occur at night and during bright sun in the forenoon.
• After a period of breeding behaviour, mating occurs with vigorous splashing of water and a number of scales may get dislodged while some fish may even sustain minor injuries.
• After spawning is over, a thick blanket of eggs is left behind at the spawning site.
• The spent fish in bundhs move to the deeper areas.
• No single factors can probably be attributed to spawning of major carps in bundhs and rivers.
• The act of spawning involves the completion of a chain of interrelated pre-conditions.

1. Heavy monsoon flood capable of inundating vast shallow areas is believed to be a primary factor responsible for spawning. Some workers believe the availability of shallow spawning ground to be a deciding factor for spawning. The rise in the level of water, naturally or artificially, is known to bring about spawning.
2. The temperature of water for spawning is found to be between 22 and 33°C.
3. Other factors like pH, high Dissolved Oxygen, alkalinity, chloride and minerals do not seem to play any significant role in spawning.
   Soil type is not very important.
4. Spawning is inhibited due to the presence of hormone-like secretion in captive waters.
5. Water that has flown through a dry bed of land rich in humus has stimulatory effect on spawning.