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2021-12-10 10:23:13

This article is the second in a series on biodiversity. A United Nations meeting on biological diversity began virtually in October and will conclude in person next year in Kunming, the capital of Yunnan province. View the entire series here.

For 54-year-old fisher Zhou Guangjin, encountering a dolphin in the waters near Shantou, in south China’s Guangdong province, is always cause for excitement. “When I was a teenager, we often saw Chinese white dolphins,” he says. “But nowadays, you rarely see any.”

One of the most recognizable individuals off the coast of Shantou is Liangshu, a female Chinese white dolphin first spotted some 26 years ago by Zhou’s captain and the animal’s namesake, Uncle Liang. Back then, her skin had already turned from grey to white, a sign of adulthood, and she already had the mysteriously collapsed dorsal fin that makes her so easy to spot.

When I was a teenager, we often saw Chinese white dolphins. But nowadays, you rarely see any.

In those days, Liangshu was one of many Indo-Pacific humpback dolphins, as the animals are also known, who have called the bays around Shantou home for centuries. But the various effects of China’s rapid economic development — overfishing, pollution, land reclamation — that have harmed so much of China’s coastal wildlife have damaged the dolphins’ habitats. Now, Liangshu’s pod is down to 13 individuals, and scientists fear their numbers will only continue to drop.

There are an estimated 6,000 Indo-Pacific humpback dolphins left in the world, spread over a triangle between China, India, and Indonesia. Two-thirds of them live in Chinese waters. In 2017, the International Union for Conservation of Nature moved the species from “near-threatened” to the more alarming “vulnerable,” and their decline in numbers has yet to be stemmed. About 2,000 Indo-Chinese humpback dolphins, the largest group in the world, live near the Pearl River Estuary, close to Hong Kong. Every year, their population declines by 3%.

Worryingly, the smaller the group of coastal dolphins is, the harder it is for them to survive. Liangshu and the dozen other dolphins near Shantou could well be caught in an irreversible downward spiral toward extinction. Elsewhere along China’s coast, other groups aren’t faring much better. For example, the Chinese white dolphin population near Xiamen, in neighboring Fujian province, has dropped to 79 individuals. Another pod that lives further north, near the city Ningde, is down to just five dolphins.

Marine biologist Zheng Ruiqiang, who grew up near Shantou, has studied Chinese white dolphins for over a decade and Liangshu’s pod for the past four years. Liangshu is the senior in the group, and also one of its most active and adventurous members, he says. The dolphins often team up, and Zheng has seen Liangshu swim with different companions. Usually, it’s her best friend, Mirka, another female, who is named after the wife of Roger Federer, the favorite tennis player of Zheng’s colleague. Female dolphins usually form alliances to protect their children and to defend themselves against harassment from male dolphins.

Liangshu (left) and Mirka (right) protect the calf Hope as they swim in the waters near Shantou, Guangdong province, 2018. Courtesy of Zheng Ruiqiang

Liangshu (left) and Mirka (right) protect the calf Hope as they swim in the waters near Shantou, Guangdong province, 2018. Courtesy of Zheng Ruiqiang

Over the years, Liangshu and her pod have faced a multitude of threats. The Chinese white dolphin is a coastal species that mostly lives within 3 kilometers of shore, a habitat rife with human activity. Some dolphins have been entangled in fishing gear or hit by vessels — Zheng suspects Liangshu’s fin collapsed after she was hit by a boat’s propeller. Noise from construction projects or marine traffic disrupts the dolphins’ echolocation abilities, causing them to lose track of where they are and become beached.

In 2017, when Zheng began working at Shantou University, little was known about how many dolphins lived in the waters near Shantou and what their living conditions were like. Looking up older data, he found there had been at least 20 dolphins back in 2010, putting the small pod’s population decline at 35% in just the last decade. One of the most impactful changes during that time was the 20-square-kilometer land reclamation project Shantou began in 2011. For the city, such a major project was a sign of its improving fortunes. But for the dolphins, it spelled disaster.

It’s much easier to protect than to repair the ecosystem.

Apart from noise pollution and other impacts of the construction process, land reclamation projects often transform the coastal environment and ecosystem, reducing the variety and number of fish. Such changes are hard to reverse. “It’s much easier to protect than to repair the ecosystem,” says Yu Wei, the Chinese White Dolphin program officer at One Planet Foundation. “It’s very difficult to completely recover the ecosystem after the area has been developed.”

The new land divided the dolphins’ habitat between a northern and southern half. Zheng has observed that most dolphins have since stopped travelling between the two halves, as the sea in front of the reclaimed land is all but devoid of fish to feed on. Liangshu is one of the few dolphins adventurous enough to go out on excursions.

While basically all groups of Chinese white dolphins face similar threats, small populations of dolphins are most vulnerable. Research has found that the benefits of protective measures decrease when a population of coastal cetaceans —  whales, dolphins, and porpoises — drops to around 500. When a population decreases to about 100 or fewer, extinction becomes highly probable no matter what management measures are adopted. As Zheng sees it, the eventual disappearance of Liangshu's pod of 13 is almost unavoidable.

Smaller dolphin populations are more vulnerable because, for one, they need to expend more effort to find food. Having studied both the large group at Pearl River Estuary and smaller pods at several locations, Zheng’s daytime observations have found that the Pearl River Estuary group spends on average 72% of their time searching for food, compared to 84% for the small pod in Shantou. That leaves these highly sociable animals much less time to socialize, mate, and rest.

The smaller the group, the harder it is for calves to survive — especially when their living conditions are less than ideal. Chinese white dolphins procreate slowly. Adult females, who are at least 9 years old, usually have one calf every three years, with pregnancies taking 11 months. With habitats broken up, there is limited genetic exchange between pods, and inbreeding becomes a risk. Liangshu and Mirka are seniors and probably the only females left in their pod.

After Liangshu’s four-year-old calf Kane died in 2014, her pod didn’t have any newborns for four years. In 2018, on a voyage to search for dolphins, Zheng suddenly spotted a grey dolphin calf swimming between Liangshu and Mirka. It soon became big news in Shantou, with people circulating touching video clips of the two white dolphins protecting the calf. Zheng was thrilled too. He had believed the pod was doomed, but the calf gave him a glimmer of optimism. He named the newborn “Hope.”

Two weeks later, when Zheng went back, he didn’t see Hope by Liangshu’s side. Liangshu was not quite herself. She would usually swim away swiftly whenever a boat came close. But on that day, she just floated in the sea, swimming slowly even when Zheng’s boat drew near. He concluded Hope was probably no more. “It is just impossible for calves to survive in such a bad and dangerous environment,” he says.

Three dolphins leap from the water in Qinzhou, Guangxi Zhuang Autonomous Region, 2020. Courtesy of Zheng Ruiqiang

Three dolphins leap from the water in Qinzhou, Guangxi Zhuang Autonomous Region, 2020. Courtesy of Zheng Ruiqiang

“In a way, dolphins are similar to human beings,” Zheng says. “When their children die, their behaviors and reactions become slow, as if they were mourning.” Other mother dolphins Zheng has observed carried their dead calves on their backs, sometimes for days, until the only thing left from their children is their skin.

Although Chinese white dolphins have been listed as Grade 1 National Key Protected Animals in China since 1989, there is insufficient study of and protection for the animals to keep their population figures from dropping. A lack of accurate and comprehensive data for the different pods along the country’s coast makes it hard to assess which measures are most effective.

The Chinese government has not been idle. In 2017, the Ministry of Agriculture issued an action plan to protect Chinese white dolphins, highlighting major risks like habitat loss, water pollution, and decline of genetic diversity. It set the goal of limiting Chinese white dolphins’ population decline in key areas by 2021, and required local governments and institutes to get a clear grasp of the species’ current status and the major factors threatening its survival. By 2026, 90% of Chinese white dolphin habitats should be protected and repaired, it said.

Since 1997 the government has established seven nature reserves specifically to protect Chinese white dolphins. In these areas, construction, fishing, and other activities are illegal. But the effectiveness of these reserves is questionable. In some cases, the dolphins have moved away from habitats these reserves are protecting. In Shantou, for example, the Laiwu Chinese White Dolphin Nature Reserve approved in 2003 only covers a small part of the dolphins’ range. In Shantou’s second nature reserve, also approved in 2003, no Chinese white dolphin has been recorded for a decade. Similarly, in Xiamen, recent research has concluded that nature reserves established in 2000 no longer cover the regions where Chinese white dolphins are most active.

The staff who oversee these reserves have limited law enforcement powers. Their daily tasks mostly consist of reminding people caught fishing in the areas that they should go elsewhere. In addition, some behaviors that have clear impacts on ecosystems, like fish farming, are not listed in the regulations for nature reserves, making it difficult to crack down on them.

If there is no respect for nature, there will be no chance for these species.

Even China’s largest group of white dolphins, who live near the Pearl River Estuary and enjoy the protection of the highest level nature reserve, are possibly in dangerous decline. World Wide Fund for Nature in Hong Kong warned last year that “the population appears to be rapidly heading below the minimum number needed to sustain it.”

“We can say for sure that the large population of Chinese white dolphins will one day become a small population if we don’t make changes,” Zheng says. “If there is no respect for nature, there will be no chance for these species.” 

To him, it’s not just about dolphins. Ten years ago, Shantou fishers could still catch fish in coastal waters. But with overfishing and overdevelopment, they have lost their livelihoods in much the same way that dolphins have. “One day when there are no more fish in the sea, all the dolphins, all the marine stories, and all the fishing culture will disappear,” he says.

Zheng, who last year became the scientific director for environmental NGO China Blue, continues to study the Shantou pod. On this most recent voyage, earlier this year, he once again spotted Liangshu swimming up and down the Shantou coast in search of food. But Mirka, her best friend, was nowhere to be found.

Tun Jianqiang, or “Strong Dolphin,” who has sustained multiple injuries after becoming entangled in offshore fishing gear, swims in the sea in Qinzhou, Guangxi Zhuang Autonomous Region, 2019. Courtesy of Zheng Ruiqiang

Tun Jianqiang, or “Strong Dolphin,” who has sustained multiple injuries after becoming entangled in offshore fishing gear, swims in the sea in Qinzhou, Guangxi Zhuang Autonomous Region, 2019. Courtesy of Zheng Ruiqiang

Editor: Kevin Schoenmakers.

(Header image: A Chinese white dolphin leaps from the water in Jiangmen, Guangdong province, 2018. Courtesy of Zheng Ruiqiang)