IT is not good news the country’s biggest natural fish breeding reservoir at Halda river is losing major fish population. The river, the lone source of natural carp breeding in South Asia, has lost at least 26 fish species in the past seven years and water pollution and unplanned construction of dams and dikes on both side of the river are mainly blamed for it. The 98-kilometre long river is increasingly becoming polluted for release of factory residues from both sides, in addition to siltation, impact of tobacco farming and sand extraction. Media reports said the river stream has become slow and water level low for construction of dams and other structures over the past four decades causing ecological imbalance to riverbank and food chain, resulting in fewer supply of plankton and benthos so essential as food to various fish species.
The Water Development Board and Local Government Engineering Department have set up dams and rubber dams on the tributaries of Halda; which brought boon for farmers but eventually endangered the river and its rare fish species. The development projects such as dams and dikes have backfired when it comes about sustaining the fish species. Halda is a valuable reservoir for fish breeding and it can’t be disturbed by human activities. We want to bring the matter to the notice of the government that the tranquil river has hardly any replacement as far as fish farmers take collection of carp eggs and other fish fry of as many species from this source. Any disturbance to it will be irreparable.
The river in south-eastern Bangladesh originates from a Hill Ranges in Ramgarh upazila in Chittagong Hill Tracts and flows through hilly areas of Fatikchhari, Hathazari, Raozan and Chandgaon upazila till it fells into Karnaphuli River. The river is reasonably deep and navigable by both big and small boats. Researchers said there were 76 fish species in 2009 and the figure has steadily come down to 50 now. This is a rich reservoir that supplies almost all popular fish species that people eat in the country.
It appears the river at its place of origin has an expanse of tobacco farming and harmful ingredients like pesticides and fertilizers ultimately falls into the river and get mixed in water. This in turn affect underwater ecosystem. Factory waste is also accountable for the presence of harmful chemicals in the water. Planktons get rot in the spawning period (April-June) downstream while its concentration is high at the same location during post spawning season (July-October). It records the lowest amount of biotic and benthic at the some other points where rubber dams are in operation.
We suggest the government should effectively protect the river as egg reservoir of various fish species; which travel to the tranquil water from sea to the upland. Disposal of waste of industries also needs to be strictly regulated to protect mother fish from disturbances.
