Excitement runs high among the fishermen across the two banks of river Halda as they are waiting for thunderstorms accompanied by heavy downpour and onrush of hilly water, which create congenial atmosphere for mother fishes to release eggs.
Over 1,300 fishermen, along with their 500 boats, have already reached Halda River to collect eggs. According the fishermen, experts and scientists of Halda River Research Laboratory, different natural factors like temperature of water, strong currents and thunderstorms create a congenial atmosphere for the mother fishes to lay eggs in the river.
As full moon will be appearing today (Saturday), it will be the high time for mother fishes to release eggs if thunderstorms accompanied by heavy shower occur and the river experiences rush of hilly water.
As soon as mother fishes release eggs, several hundred spawn collectors start collecting eggs from different points of the river. “At the beginning of April, indigenous fish species migrate from different rivers to Halda to release eggs. But mother fishes’ egg release depends completely on nature. If heavy rain and thunderstorm occur with hilly water coming down speedily during the full or dark moon, mother fishes release eggs in the river,” Mohammad Shah Alam, focal person, Halda River Project, told Bangladesh Post on Friday.
He added mother fishes usually release eggs on a trial basis at first. “Mother fishes spawn finally if they find the aquatic environment congenial,” he said. The fishermen in association with the Halda River Research Laboratory and district administration have already prepared 400 small ponds across the banks of the river to collect the eggs. Besides, the district administration has also renovated about 50 small ponds.
According to the Halda River Research Laboratory, popular species of mother fishes which are locally known as Rui, Katla, Mrigel and Kaliboush will release sufficient amount of eggs in the river this season. Halda is a river in south-eastern Bangladesh. Originated from the Badnatali Hill Ranges in Ramgarh Upazila in the Chittagong Hill Tracts, the river flows through Fatikchhari Upazila, Bhujpur Thana, Hathazari Upazila, Raozan Upazila and Chandgaon Thana of the Chattrogram metropolitan City to fall into the Karnaphuli River.
The 81-kilometre long river has a very turbulent tributary. The river is famous for breeding pure indigenous species of fishes, and it is the only the indigenous species of fishes’ natural breeding field of Bangladesh, perhaps in South Asia. These species of fish release their eggs at a certain period of the monsoon and fry-collectors collect those eggs through a unique method to sell them among the fish farmers. And the fertilised eggs soon start to develop fish fry within 96 hours and one kilogram fish fry is sold at Taka 40 thousands.
After collecting the eggs, the fishermen nurture the eggs in clay pots and also in cisterns of different hatcheries set up by the Fisheries Department. After 96 hours, the eggs usually transform into fries which are then sold out to the fry collectors or hatchery owners. According to the Halda River Research Laboratory, the fishermen collected 22,680 kilogram eggs last year. And about 378 kilogram fish fries were developed from the eggs. The fishermen earned Taka 15 crore by selling the fish fries.