What is the future of sea mammals in Bangladesh?

It was not Ismael from Moby-Dick. Neither was it the CGI-infused, distorted whale hunting scene from Chris Hemsworth's In the heart of the sea. 

My grasp of the plight of whales and dolphins - that they faced in the whaling heydays and are still struggling with - was helped by a small group of whales. 

History has labelled them as right whales. When I was facilitating a course on marine mammals, I dug a little about their gruesome past. 

Right whales have heat-insulating fatty blubbers under the skin, which is a common feature of whales, dolphins, and porpoises. But, theirs are one of the thickest. 

These large-headed giants thus stay less buoyant, more sluggish, unable to do a steep dive in case of emergency, and the whale-hunters  find them as their 'righteous' kill. 

Harpooning the whales for prized fats, perfume, and meat reached an industrial level by the 18th century. 

By the mid-1800s, the profit in the trade of whale-based products reached 230 million pounds only in the United States. 

According to a research published in 2014 in the journal Marine Fisheries Review, within a century, three million whales were culled to meet the demand. 

The hunting did not cease until the 1980s. By and large, cetaceans are yet to manage the past trauma. Only 383 individuals of right whales are now surviving in the North Atlantic. 

So, the fact that cetaceans still live in the Bangladeshi waters makes me think how lucky we are to have them. 

Evolutionary wonders

Cetaceans are mammals like us but live under water. They breathe with lungs – just like us! They have a tail-fluke, which is, unlike the vertical tail fin of fish, appended horizontally. 

Their hands are now flippers to serve the works of frontal fins of fish. They also have dorsal fins, which makes swimming further streamlined. 

It is proved that predecessors of whales were once land-dwellers like us. In course of evolution, they had returned to water again. 

The recent whale corpses have drawn our ever-fleeting attention, which should not be squandered by spreading a fictitious love story in the mainstream media

To retain body heat, they are insulated by body fat. This feat enables them to venture into sub-zero waters. 

To keep water out while inhaling and to breathe with ease, the nostril has migrated to the top of the head. We call them blowholes. They have developed glands to filter out excessive salts. 

Cetaceans have conquered the rivers where light penetration is a bare minimum. There, cetaceans have reduced eyesight; some are literally blind. 

Instead, they have developed acute hearing senses. As sound travels less and slower under water, cetaceans have mastered sound production. 

We define the feat as echolocation – the art of producing sound, and, by the nature of reflected sounds, sizing the potential prey, or setting a proper course. 

The most astounding feature of cetaceans is their intelligence. Let it be the vastest blue or the murkiest estuaries, cetaceans are social, maintain small groups, do vibrant inter- and inter-group communication, and teach the young hunting techniques including use of tools. 

They can love expressively and explicitly. Whales can sing to impress the partner. Dolphin males are LGBTQ flag-bearers, known for inter-species affairs. 

Peter, the bottlenose dolphin exploited in a NASA-funded project, fell in love with a researcher in the 1960s. The project was to decipher the language; not continued, and dubbed 'unsuccessful'.

Peter was relocated to a public display, he later committed suicide not able to bear the 'separation'.

Right whales are sluggish, but there are killer whales, the largest dolphin, that can swim 55 kilometres per hour. Porpoises, a smaller, shallow-water relative of dolphins, also swim fast; all seven of them do. 

Blue whale is the largest, we know, and it is also the fastest whale, capable of swimming about 40 kilometres per hour. But, this speed is not enough to outswim the whalers. 

Once the slow bowhead whale stock ran out, blue whales came into the harpooner's crosshair. Rocket-propelled techniques were discovered and the blue whale population dropped by 90%.

How many do we have?

According to the 2015 assessment provided by IUCN (International Union for Conservation of Nature) Bangladesh, we have 11 cetaceans in the country.

Two dolphins dwell in rivers, Ganges river dolphin from all the large rivers to the estuary openings, Irrawaddy dolphin in estuaries. The rest are oceanic. 

We have one true, toothless whale: Bryde's whale. Spinner dolphin, Pantropical spotted dolphin, and rough-toothed dolphin frequent our bay. There are genetically distinct populations of the Indo-Pacific bottlenose dolphin and humpback dolphins in our bay. 

We have two toothed whales: False killer whale and sperm whale - both of them are closer relatives of each other than they are to toothless whales.

Toothless whales eat by a sieving mechanism.

After a quick look at the Handbook of whales, dolphins, and porpoises of the world, I realised that roughly about 15 more species might also live in the bay. 

There are some for-sure species like striped dolphin, Risso's dolphin, fin whale complex. Possibilities of wild card entries like beaked whales are not derelict.

The Coromandel Coast of the Bay of Bengal has records of about 25 cetaceans. Our side should have a closer tally. 

Newly and rapidly emerging threats

Commercial whale-hunting is now mostly controlled, albeit not stopped. Countries like Japan keep doing it. There are also new threats, becoming more lethal and causing silent damage. 

Sonar activities and bustling shipping routes are two prime examples. Cetaceans, large and small, are prone to accidents by propellers. 

Dolphins entangled in nets can be drowned, not being able to surface in time. They are often beaten-up and mutilated by fishers, for damaging the net. 

According to a 2011 study published in Marine Mammal Science led by Wildlife Conservation Society (WCS) Bangladesh, about one-third of the 1700 Indo-Pacific bottlenose dolphins of the Bay of Bengal showed injury marks inflicted by fishing gears.

Excessive fishing and overfished stocks drive dolphins to starvation. Recently, tuna fishing from the high seas was proposed in Bangladesh. 

The tuna stock of the Indian Ocean has plummeted. These fishes are in the food chain of many whales and dolphins. Industrial fishing without considering cetaceans could be a fatal blow.

Plastic pollution is another addition to the cetacean woes. All recent carcasses were cramped with plastic, reports say. 

A sperm whale washed up in 2019 in the Scottish Hebrides had 100 kg of plastic, torn net, floaters, and ocean debris in the gut.

Scientific investment is urgent

Yes, we have protected areas for cetaceans. There are three sanctuaries in the Padma for the Ganges river dolphin, three in the north Sundarbans for both the Ganges and the Irrawaddy dolphin. 

The Halda River, the Bangabandhu Fisheries Heritage, also safeguards an important river dolphin population. The Swatch of No-Ground (SONG), a trough in the Bay of Bengal, is a Marine Protected Area since 2017. 

In 2020, the waters around the Nijhum Dwip received the same status. While chalking out sanctuaries is a buttressing step in cetacean conservation, frequent, rigorous, and systematic research efforts are time's demand. 

WCS Bangladesh's 2006 count of the Ganges river dolphin and the Irrawaddy dolphin in the Sundarbans mangrove stood at 226 and 451 respectively. 

An update on this estimate is urgent. More work is also needed on the SONG, particularly on the population status and abundance of cetaceans, and their ecological drivers. 

Compared with their oceanic cousins, the brunt of pressure on the river dolphins is glaring. 

Sushuks are dying out in rivers, caught in nets, hit by propellers, isolated by dams, persecuted for oil, and starved to death. 

We are yet to know the underlying factor or to formulate any effective measure to curb down the death rate. Our limited knowledge on cetaceans is not a hypothesis. IUCN Bangladesh says we just do not have enough data on five of the 11 of our cetaceans. It was in 2015 when we  realised that we know almost nothing. 

The Conservation action plan for Ganges river dolphin and Irrawaddy dolphin of Bangladesh that came out in 2019, a first-of-a-kind attempt to save dolphins, highlights the points discussed here. 

But, I fear, we might not have enough time. The global status of both of the species has deteriorated lately. River dolphins are dying. Ocean-dwellers are far from known.

The picture of the Sonadia dolphin, hung upside down under a baking sun, and oil dripping from its almost unrecognisable remains still haunts me. 

On Whale, dolphines deaths in the Bay

Whale and dolphin casualty in our bay is not a rare occasion. In recent times, including the two washed-up whales of Cox's Bazar, at least 10 cetacean deaths occurred in the bay. 

In 2020, a whale remains was spotted on the Bangla Channel and four porpoise carcasses were found in St. Martin's island by scientists. These deaths were not investigated. The mysterious deaths and disappearance of pods of dolphins from the Cox's Bazar off-shore has not been inquired either. 

The recent whale corpses have drawn our ever-fleeting attention, which should not be squandered by spreading a fictitious love story in mainstream media. 

Autopsy to check for propeller injury, proper research on the gut contents to look for plastic poisoning, and stringent monitoring on the bay to measure the effect of sonar are the to-dos. Before making deductions out of thin air, we must make reasonable investments in science.