Hong Kong Fauna: Can We Save the City’s Last Remaining Dolphins?

A dolphin hunting near a purse seine. Photo courtesy HKDCS.

The boat speeds away from the Tung Chung Ferry Pier, leaving behind shopping malls plastered with brand names, snake coils of tourists and jam-packed bus terminals. What gradually comes into sight is a prehistoric paradise of lush islands, reddish volcanic rocks and pristine beaches. Terns and tropicbirds glide alongside the hull above the shimmering water. “It looks as if we’ve ventured into a different world, but we’re actually in western Lantau,” says Taison Chang, chairman of the Hong Kong Dolphin Conservation Society (HKDCS).

Together with his small team of two surveyors, he is looking for elusive sea creatures: Chinese white dolphins. They are native to Hong Kong waters, and they have become a beloved symbol of the city, but climate change, pollution and land reclamation have thrown them into critical danger. It’s not clear whether Hong Kong’s dolphins can survive another generation.

The earliest local record of the dolphins, also known as pink dolphins and Indo-Pacific humpback dolphins—and scientifically as Sousa chinensis—dates back to the 1600s. As can be deduced from their name, these dolphins live in the Indian and Pacific oceans, from the coastlines of southeastern China to Thailand, Malaysia and eastern India. That includes the Pearl River Estuary, the brackish area just west of Hong Kong. “Chinese white dolphins are very picky – they only feed on fish in the estuary,” says Chang. In Hong Kong, they tend to frequent the waters near Castle Peak, Lung Kwu Chau and the Sha Chau Marine Park, Tai O and Chek Lap Kok, as well as Fan Lau and the Soko Islands to the south of Lantau.

A dolphin’s maturity can be determined by how much its grey pigment has faded. Photo courtesy HKDCS.

As the boat sails further from Tai O, Charlotte Lau, Chang’s colleague, spots a dolphin circling around a grey lump. “It’s a mother teaching her calve!” she exclaims, before discovering more pink tails and blow holes emerging near the boat. Similar to other types of dolphins, these are sociable and curious animals, and they are often seen breaching, porpoising and tail-slapping to hunt in groups, or spy-hopping to peek at things happening above water.

But what distinguishes Chinese white dolphins from other species of cetaceans is their colour: not exactly white, as their name would imply, but more pink. The Pearl River Delta population is the pinkest of the lot. And yet scientists are unable to explain their distinctive colour, which is starkly different from other whales, dolphins and porpoises that are white, deep blue, brown or dark-coloured. “Colours are nature’s great tactic of camouflage,” Chang explains. “It’s not easy to spot a prey that has a dark-coloured back in the deep blue sea or a white belly against the bright sky.”

Chinese white dolphins used to be accused as “sea pigs” by fishermen for feeding on their fish stocks. Photo courtesy HKDCS.

Chinese white dolphins are a curious case. Although their calves were born with a protective grey colour, their pigments gradually disappear as they mature. Some marine scientists attribute this to the dolphins being top predators in the region, which implies that they no longer need camouflage for protection, whereas others argue that pink is their camouflage colour instead in the turbid estuary, where the light-coloured sand, grit and particles make their paleness an advantage for hunting.

Adding to that strangeness is their name – if they are pink, why are they called Chinese white dolphins? “The adult dolphins don’t have any pigments in their bodies,” says Chang. “It’s the blood that gives them the pink colour.” Dolphin corpses, therefore, are white because their blood is no longer circulating. The misnomer likely emerged from fishermen’s oral accounts that generalise the dolphins as “pale” creatures in the past, as well as old photographs which fail to capture their colour in detail.

It’s exactly this particular nature that has made the dolphins one of Hong Kong’s most renowned animals. In 1997, Chinese white dolphins were chosen by the Hong Kong Celebrations Association as Hong Kong’s official handover mascot. According to former association chairperson Raymond Wu, the dolphins’ social nature reifies the animal’s strong familial bond. Every year, after migrating away, they return to the Pearl River Delta to breed, which further cemented the association’s choice of the dolphins as a symbol of Hong Kong’s return to the motherland. It was nothing if not an aspirational choice of mascot.

A mother and her calve. Photo courtesy HKDCS.

And yet the fate of the Chinese white dolphin is anything but auspicious. The Hong Kong Cetacean Research Project has been conducting research on the cetaceans since the 1990s, when construction began on the new Hong Kong International Airport on Chek Lap Kok. What researchers have found is shocking: a precipitous decline in the dolphin population since the airport opened in 1998. That has been exacerbated by the new Hong Kong-Zhuhai-Macau Bridge; since construction on the bridge began in 2009, the average daily density of dolphins has plummeted by half. There were 188 dolphins in Hong Kong waters in 2003; today, there are only 47. Researchers estimate that there are only 1,500 to 2,000 dolphins left in the entire Pearl River Delta.

Chang says there have been no dolphins seen near the bridge since construction began. Construction noise made life difficult for the dolphins, who depend on echolocation to navigate, hunt and communicate. The finished bridge also blocks passage through their main local habitat, splitting it into smaller habitats that create greater competition for food among the dolphins. “Overfishing has led to a drastic drop in their food source, which draws them closer to fishing boats where accidents take place,” says Chang.

Chinese white dolphins aren’t the only marine mammals affected. Their much more elusive and lesser-known cousins—the narrow-ridged finless porpoises (Neophocaena asiaeorientalis) and Indo-Pacific finless porpoises (Neophocaena phocaenoides)—which live a little further away from the eastern China coastline, also face the same threats. Marine traffic in the estuary is extremely heavy, with turbojets travelling between Hong Kong and Macau every 15 minutes, not to mention cargo ships, police boats, speedboats, fishing boats and dolphin-watching walla-wallas competing for space in the same water as the dolphins. Porpoises and dolphins are sometimes injured by boat propellers and fishing gear.

“The cuts, sometimes even mutilations, make it extremely hard and painful for them to hunt,” says Chang. In 2015, a Chinese white dolphin identified as WL212—more famously known as Hope—was found wounded by a propeller with four extremely deep cuts. The dolphin’s condition was so serious that it was controversially euthanised by the Ocean Park Conservation Fund (OPCF) Cetacean Stranding Response Team and the Agricultural, Fisheries and Conservation Department.

Water pollution adds to the dolphins’ woes. “Our team has observed red rashes on the skins of some individuals,” says Chang. “The recent annual reports published by OPCF investigating the causes of deaths of Chinese white dolphins and finless porpoises point out that cancer has been noted in the certain cetacean populations.” He attributes this to the chemical waste discharged into the Pearl River by agriculture and industry, as well as marine debris such as plastic that breaks into small particles that are inhaled by marine animals.

These conditions have led both finless porpoises and Chinese white dolphins to be categorised as vulnerable in the International Union for Conservation of Nature’s Red List of Threatened Species, indicating that they are likely to become endangered unless the circumstances that are threatening their survival and reproduction improve.

Their disappearance would take a heavy toll on Hong Kong’s ecosystem and human life; it isn’t just a question of finding a new mascot to represent the city. Both the finless porpoises and Chinese white dolphins are keystone species and top predators, meaning that they carry the ecological role of monitoring the food chain in the region’s waters. “If they become extinct,” Chang warns, “there may be an overpopulation of their preys down the food web, leading to an imbalance in the marine ecosystem. Some potential consequences include algae bloom, and in the long run, more frequent extreme climatic conditions as our ocean which helps regulate climate is adversely affected.”

A mother and her calve porpoise, or jump out of the water, to travel faster over a longer distance. Photo courtesy HKDCS.

The government has responded to the decline in dolphin populations by setting up two marine parks, but Chang says this isn’t enough. “The locations aren’t ideal and they aren’t sufficient at all,” he says. For a decade, NGOs such as HKDCS and the World Wildlife Fund Hong Kong have been working on public education through university training programmes and school talks, as well as urging the government to stop expanding the airport, which is currently building a third runway. They also want high-speed ferries to be rerouted so they don’t overlap with the cetaceans’ major feeding grounds, and they think the government needs to expand its marine parks. “But the government leans towards economic development and isn’t doing anything practical to curb the cetaceans’ worsening and worrisome decline,” says Chang.

The only ray of hope is a growing awareness of the dolphins’ plight among the general public. There are more and more conservation campaigns such as ocean cleanups and screenings of films about the vulnerable species, such as young wildlife documentary filmmaker Daphne Wong’s Breathing Room.

But people in Hong Kong need to make some fundamental lifestyle changes in order to make a real difference. “Start with the basics,” says Chang. “Make informed decisions on purchasing electronic devices from companies with proper waste disposal policies, reduce the use of single-use plastics and opt for sustainable seafood. Equally significantly, we all have the civic duty to voice our opinions against the government’s or ship companies’ policies, plans and practices that harm marine life.”

Back off the coast of Lantau, the boat approaches a dolphin. “There you are, WL232,” says Chang’s colleague, Vincent Ho. The dolphin is marked by three deep cuts from its fin to tail, which the team first discovered last year. Chang says the wounds are very similar to those suffered by Hope, but unlike the euthanised dolphin, this dolphin—wagging its tail and busy circling around a school of fish—seems to be healing. “These cetaceans are resilient animals thriving in un-idyllic conditions,” says Chang.

Perhaps WL232 is the new Hope – and with Hongkongers’ growing concern for Chinese white dolphins and finless porpoises, there could still be hope for their future.

 

The Hong Kong Dolphin Conservation Society organises dolphin watching and survey tours, available in both English and Chinese, from time to time. Please visit their Facebook page for more information.

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