A total of 27 dolphins died in Halda river, since September 2017
International Freshwater Dolphin Day is being observed at a time when the dolphins of the country are passing through a very tough time as they are dying on a regular basis mainly due to anthropogenic or man-made reasons.
As a reminder, a Gangetic dolphin (Platanista gangetica) with injury marks was found dead in the Halda river on October 13.
On August 14, another dolphin was found dead at Modunaghat point of the river on August 14.
According to researchers, rampant pollution, using dredgers for lifting river sand, shallow water and plying of mechanized boats are sharply reducing the dolphin population in the Halda.
“It is an ominous sign for the conservation of the dolphins in the region that 27 dolphins have so far died in the Halda river since September 2017,” noted Halda researcher Prof Dr Manzoorul Kibria said while speaking with Dhaka Tribune.
“Dolphins, locally known as Shushuk, were frequently spotted while ferrying the Karnaphuli river on a boat. Regrettably, the dolphins have now become a rare right in the river due to mindless pollution,” said Aliur Rahman, general secretary of Movement to Protect Rivers and Canals of Chittagong.
According to marine biologists, dolphins are an indicator species, meaning their presence, abundance, or lack of abundance demonstrate the quality of an aquatic environment.
The first condition for dolphins’ existence is clear and pollution-free water, Prof Sayedur Rahman Chowdhury of the Institute of Marine Sciences at Chittagong University said.
“Dolphins are called bio-indicators. So, the presence of a great number of dolphins in a particular area is an indicator that the area has pollution-free water,” he said.
“However, the untreated solid and liquid waste from industrial units and households are posing a serious threat to the aquatic ecological balance.
“The oil seeping from the vessels and engine-run boats are also posing a threat to the dolphins. Moreover, the overfishing practice is creating a food crisis for the aquatic mammals,” Sayedur also added.
Fishermen should stop the use of gill nets as dolphins get entangled in it, he mentioned.
Dolphins play crucial roles
“Dolphins help us gauge the extent of pollution of a river,” said Abu Naser Md Yasin Newaz, Chittagong divisional forest officer (Wildlife Management & Nature Conservation Division).
“Dolphins maintain the balance of the aquatic environment and indicate the abundance of fish and health of a river. Moreover, an injured or dead dolphin signals to illegal activities in a river.
“Dolphins also minimize the risk of disease transmission through preying on sick and weak fish. As a result, dolphins play an important role in increasing the number of healthy fish and minimize the risk of food poisoning for humans,” Naser added.
Two types of dolphins are found in Bangladesh- Irrawaddy dolphin (Orcaella brevirostris) and Gangetic dolphin (Platanista gangetica).
The official status of the river dolphins, locally known as Shushuk [Platanista gangetica] is “critically endangered” as per the International Union for Conservation of Nature (IUCN) Red List.
The IUCN Red List of Threatened Species is a universally recognized index of the world’s endangered animals.
Committee to protect dolphins
As per the Wildlife (Conservation and Security) Act-2012, any person killing a dolphin shall be deemed to have committed an offence and for such offence, will be punished with imprisonment for a term not exceeding three years or with a fine not exceeding Tk3 lakh or with both, and in case of his repetition of the same offence, he shall be punished with imprisonment for a term not exceeding five years or with a fine not exceeding Tk5 lakh or with both.
On May 19, the High Court formed a committee headed by the deputy commissioner of Chittagong to stop the killing of river dolphins and broodfish while protecting the biodiversity of Halda river.
The bench of Justice Obaidul Hassan issued the order during a virtual hearing when two reports on the matter were placed before it by the director-general of the Department of Environment and deputy commissioner of Chittagong.
The court also asked lawmakers elected from areas near the banks of the Halda to act as advisers to the committee.