Reports of dead dolphins washing ashore or floating in rivers have surged in recent years
Dolphins are calm and innocent animals. They are social mammals, often living in pods of a dozen or more in rivers or oceans. Whether dolphins have a language, as humans do, is a topic that foreign scientists have debated for decades.
Prof Md Shafiqul Islam, director of the Institute of Marine Sciences and Fisheries at Chittagong University, made the remarks while talking about these aquatic mammals.
Experts in Bangladesh say that the country once had a huge dolphin population, and the reason behind dead dolphins washing ashore or floating in rivers in recent years is not clear-cut.
Over the past few years, especially during the pandemic, both social media and lately news platforms have been reporting news of the dead and sometimes decomposed dolphin bodies being washed ashore. According to those keeping abreast of the issue, in most cases, these dolphins had wounds or were injured.
Injuries, hunger or something else?
Cox’s Bazar Fisheries Officer SM Kamruzzaman told Dhaka Tribune: “We found three dead dolphins in 2019, five in 2020 and three in 2021 on the coast.
“From post-mortem examinations and observations of the last three, we learned that two had died from injuries. They had wounds on their bodies and fishing nets were stuck near their mouths. The other one died from starvation.”
The dolphins are mostly getting injured after being caught in fishing nets, he said.
Collisions with large ships, getting beaten up by people, earthquakes, getting stuck in river canals for long periods without any food and old age also lead to dolphin deaths, Kamruzzaman added.
Md Zahangir Alom, country representative of Wildlife Conservation Society (WCS) Bangladesh program, said at least 65% of dolphin deaths were caused by gillnet entanglements. Fishermen use gill nets [colloquially called faash, sandi, current jaal, etc] to catch ilish.
However, experts agree that the fishermen did not cause the deaths intentionally.
Since 2007, the year the WCS started working on marine conservation in Bangladesh, the organization has observed that most dead dolphins are found from July to September and sometimes in October.
This finding implies a link between the ilish fishing season and dolphin deaths.
The ban on ilish fishing ends in June, and from July, when fishermen start fishing in the sea, reports of dolphin deaths become frequent. Collisions with big ships or speed boats also cause some of the deaths, Zahangir said.
Meanwhile, International Union for Conservation of Nature Program Coordinator ABM Sarwar Alam said collisions with big ships only account for 1% of dolphin deaths. “We also need to find out if they were suffering from any diseases,” he added.
However, Zahangir Alom of the WCS said that the organization has yet to find a recent case where a disease had caused the death of a dolphin.
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According to WCS data, there were 26 cetacean deaths in 2018, 12 in 2019, 32 in 2020 and 25 deaths in 2021 till September, while a total of 275 cetaceans were reported dead in the last 15 years.
The WCS said that Bangladesh has around 6,000 Irrawaddy dolphins, some 2,300 bottlenose dolphins and 1,500 pink dolphins. There are 250 Ganges river dolphins or shushuks in the Sundarbans and 125 in the Karnaphuli River.
Dr Md Shafiqul Islam of CU said that being mammals, dolphins drown just like humans when they cannot breathe underwater. River pollution — caused by the discharge of industrial waste, plastic and chemicals — harms the country’s dolphin population significantly.
According to the WCS, in 2010, two dolphins were found dead in the Buriganga river and three-four in the Turag River.
Asked if any measures have been taken to ensure the safety of dolphins, Bangladesh Livestock Research Institute Additional Director Md Azharul Amin said there are no projects that solely focus on dolphins, but the organization’s district officials and representatives work accordingly whenever dead dolphins are found in the coastal areas.
“We are working to raise awareness among the fishermen in those areas so that they release any dolphins stuck in their nets,” he added.