The Halda river flows through Hathazari and Raozan upazilas in Chittagong
The Halda river spawning season has begun! Spawning indigenous sweet water species of mother fishes started releasing their eggs in the Halda River on Sunday morning.
Hathazari Upazila Fisheries Officer, Azharul Alam, said mother fishes started spawning at 7:30am in Gorduara, Machhuaghona, Ajimer Ghat, and Napiter Ghat points on the Halda river.
Every year, during the Bangla months of Baishakh and Jaishtha (April and May), various species of mother fishes like Catla (Catla), Ruhi (Labeo rohita), Mrigal (Cirrhinus mrigala) and Kalbaoush (Labeo calbasu) start migrating from the Karnaphuli, Matamuhuri, and Sangu rivers, to their spawning grounds on the Halda.
The Halda river is the country’s lone natural fish breeding ground in the country.
Renowned fish researcher, Prof Dr Manzoorul Kibria, told the Dhaka Tribune that water temperature, strong currents, and thunderstorms are different natural factors that trigger the mother fishes to lay eggs in the river. The mother or brood fish usually releases sample eggs to test if the aquatic environment to release fertilized eggs is congenial or not. When they find the environment congenial, they start laying fertilized eggs at suitable places in the river, added Prof Kibria.
A veteran spawn collector on the Halda River, Kamal Sowdagor, said they are eagerly waiting for the brood fish to release eggs on a large scale, now that the fishes have started releasing sample eggs.
The Halda river flows through Hathazari and Raozan upazilas in Chittagong and is considered to be the only natural breeding ground in the world, where these species of fish release eggs at a certain time in the monsoon season. Spawn collectors then collect these eggs and sell them to fish farmers across the country.
Once they have the eggs, fishermen in many parts of the country raise the eggs in mud pots and cisterns at different hatcheries set up by the government fisheries department. The eggs usually hatch into fries after 96 hours, which are then sold to fish fry istributors or hatchery owners.