Native fish populations in the Karnaphuli River have seen a sharp decline in recent years due to untreated solid and liquid waste discharged from industrial units and households.
According to local sources, many fish species like Chitol, Rita, Modhu Pabda, Rupchanda and Borguni are not found as before.
The aquaculture specialists alleged that the local shrimp fry collectors are also blame for the depletion of indigenous fish species in the river as they use push net for catching shrimp fry.
The green activists alleged that most industries were running without Effluent Treatment Plant (ETP) facilities and thereby posing a serious threat to the aquatic ecological balance of the Karnaphuli.
Manjurul Kibria, Associate Professor in Zoology department of Chittagong University said: “Scores of fries belonging to other fish species get caught and killed for catching a single shrimp fry using push net, one of the detrimental fishing gears.”
“We have conducted a survey in 2009 to ascertain the exact number of fish species available in River Karnaphuli. Once the Karnaphuli was abound with a total of 140 fish species which include 66 species of freshwater, 59 species of brackish water and 15 species of migratory fish. However, we discovered that 20-25 species of freshwater and 10 species of brackish water have already become extinct while the rest fish species are also in peril,” said Kibria.
Referring to the rampant use of push nets, Manjurul Kibria who conducted the survey, said, Manjurul Kibria also cautioned that many more fish species in River Karnaphuli might go extinct if appropriate conservation measures are not taken on an urgent basis.
“Fish can be a major source of protein for the low and middle-income group of people in the country and we can easily meet our daily protein demand through eating fish. However, it is alarming that many indigenous fish species are becoming extinct in the Karnaphuli,” said Prof Sayedur Rahman Chowdhury, Institute of Marine Sciences and Fisheries, Chittagong University.
Prabhati Dey, District Fisheries Officer, said: “A fish usually lives on the other species. Therefore, the disappearance of a fish species will naturally have its adverse knock-on effects on the aquatic food chain. Moreover, the depletion in fish species is a clear indicator to the rampant water pollution.”
“The amount of DO (Dissolved Oxygen) is alarmingly decreasing in Karnaphuli due to the rampant pollution discharged from state-owned and private industrial units. Many types of toxic chemicals are being dumped into the river every day from several hundred small and medium mills and factories built on both banks of the Karnaphuli,” said Edris Ali, a researcher on Karnahuli River and also Associate Professor in Chemistry Department at Government Mohsin College.
“The Karnaphuli may turn into another Buriganga if the rampant river pollution goes unchecked,” warned Ali who is also Chittagong chapter Vice President of Poribesh Bachao Andolon, a green organisation.
