What can kill a blue whale?
There are thought to be no more than 25,000 living whales in the world today
Blue whales as a species are endangered creature and with Bangladesh seeing two of them washing up dead ashore back-to-back days serves as an ominous sign of the disrupted ecological balance.
Although Cetaceans (whales, porpoises, and dolphins) were previously found dead in Cox's Bazar as late as 2020 when a number of dolphins were beached, finding a dead blue whale is a rare sight.
There is a range of reasons that can lead to the mortality of blue whales and others in their species. Cetaceans can simply die from old age as their lifespans range from a few decades for harbour porpoises to over 200 years in the case of bowhead whales.
Although the creature moves in a pack, inexperienced individuals can easily get lost and become stranded leading to death. Whales can also die from diseases, parasites and even difficulties during birth.
Aside from the natural causes, the species of blue whale across the world are significantly depleted by commercial whaling activities.
Vessel strikes can injure or kill blue whales and the risk is much higher in some coastal areas with heavy vessel traffic like ports and in shipping lanes, and from larger vessels and vessels travelling at high speeds.
Blue whales can become entangled in fishing gear ultimately resulting in fatigue, compromised feeding ability, or severe injury, which may lead to death.
The Cetaceans including blue whales can also be in fatal danger for ocean noise, habitat degradation, pollution, vessel disturbance, and climate change.
In the case of Bangladesh, the whales were likely to be injured and or killed in a shallow sea zone, causing their bodies later to be stranded on the beach during tidal waves.
Senior Scientific Officer and Bangladesh Fisheries Research Institute and a PhD Fellow Mohammad Ashraful Haque told the Business Standard that the dead animal that came ashore on Friday was an adult Bryde's whale.
Bryde's whale is more specifically a rorqual belonging to the same group as blue whales and humpback whales.
"Whales usually move in groups. Whales often die if they leave their pack for any reason. The same thing could have happened to the two whales found on Friday and Saturday," he said.
Despite being unable to pinpoint the exact cause of their death, Ashraful Haque confirmed that the whales had died at least 10 to 12 days earlier.
Although almost everyone is familiar with the world's largest animal, the blue whale, in reality, very few people in the country have seen the mammal. Even people in the coastal district of Cox's Bazar have rarely seen the animal.
Earlier on Friday afternoon, a 45-foot-long blue whale was brought ashore in Himchari with the tide while another smaller whale was found dead Saturday morning.
As the news spread through the media and Facebook, curious people from Cox's Bazar city, Ramu, Ukhia, Teknaf and even Chakaria flocked to Himchhari beach.
Apart from senior officials of district administration, environment department, forest department, RAB, police, BGB and Coast Guards, scientists from Bangladesh Marine Research Institute and Bangladesh Fisheries Research Institute also came to the spot.
A team of officers and employees including the surgeon of the district animal resources and wildlife department came for the autopsy.
According to environment journalist Ahmed Gias, Cox's Bazar last saw a dead giant whale wash ashore in 1990 at Laboni Point beach that measured around 65 feet in length.
"The skeletons of dead whales washed up ashore should be preserved for educational and research purposes," he added.
Ramu Upazila Nirbahi Officer (UNO) Pranoy Chakma said an initiative has been taken to preserve the necessary parts of the whale's remains found on Friday that has been buried.
"As per the advice from marine and fisheries scientists the buried part has been surrounded so that the bones can be removed and preserved when the meat rots," he said.
Though scarce, sightings of whales have been reported near the Bay of Bengal several times throughout the decades. According to different estimates, there are thought to be no more than 25,000 living whales in the world today.
