In danger of extinction
Romer’s tree frog and the Chinese white dolphin in uphill battle to survive

By Adelaide Lau

When visitors on a dolphin-watching tour rushed from the cabin to the deck, the Chinese white dolphins were swinging their flukes, as if to say hello.

Owing to the construction of the new airport and additional port development at Chek Lap Kok, the populations of two valuable creatures in Hong Kong — Romer’s tree frog and the Chinese white dolphin — have been declining.

Romer’s tree frogs have been found on Lantau Island, Chek Lap Kok and Po Toi since 1984.

“Romer’s tree frog is an endemic species. It can only be found in Hong Kong,” said Mr. Michael Lau, a researcher in the Department of Ecology and Biodiversity at the University of Hong Kong.

“As there is no such research conducted in China, we do not know whether the Romer’s tree frog can be found there,” Mr. Lau added.

According to information provided by the World Wide Fund of Hong Kong, Romer’s tree frog is the smallest species of frog in Hong Kong. The females are slightly larger than the males and can reach two centimetres in length, from snout to vent.

Romer’s tree frog has a natural camouflage. It is brown in colour, with a dark X-shaped mark on the back.

Romer’s tree frog has poorly developed suction discs, so it spends most of the time on the ground, especially in clusters of herbs and leaves, rather than in tree canopies.

Said Mr. Lau: “Romer’s tree frogs are living on North Lantau Island, where there is clear water, dense woods and a small (human) population.

“There are approximately 10,000 adult Romer’s tree frogs in Hong Kong now. It is difficult to estimate the exact amount of them. They are too small to be easily found, and their breeding rate is very high,” said Mr. Lau.

Actually, the number of Romer’s tree frogs is on the increase due to a rescue operation undertaken by Mr. Lau and his partner, Dr. David Dudgeon.

Before the natural environment at Chek Lap Kok was destroyed, about 200 to 300 Romer’s tree frogs and tadpoles were captured. They were kept at the University of Hong Kong.

In 1993, over 1,000 tadpoles and 100 frogs were released to Tai Po Kau Nature Reserve and Tsiu Hang Special Area.

“We are satisfied with the result that some of the released frogs have bred successfully,” said Mr. Lau. Mr. Lau is now monitoring the released Romer’s tree frogs to see whether they can adapt to and breed in the new environment.

“Most of the sites for releasing frogs are suitable for them to live. We can maintain a steady population of Romer’s tree frogs in Chek Lap Kok now,” Mr. Lau continued.

However, the fate of the Chinese white dolphin is rather bleak.

“Forty Chinese white dolphins died last year,” said Mr. Chris Parsons, a research student at the Swire Institute of Marine Science at the University of Hong Kong.

The Chinese white dolphin can be found in the sea around North Lantau Island.

“Before 1993, we knew nothing about the Chinese white dolphin. They were named Chinese white dolphins because they were first recorded on a (foreign) visitor’s voyage to China,” Mr. Parsons said.

There are various colours for the Chinese white dolphin. They may be pink, white or grey in colour, or with light pink spots on the bellies. Their pectoral fins are small and round, while their flukes are round and triangular in shape.

According to Mr. Parsons, typically, the dolphins live in shallow coastal areas up to a depth rarely exceeding 10 metres, where there are small fishes.

“Usually,” said Miss Sannie Tang, a student at the City University of Hong Kong who has joined the dolphin watching tour several times, “the dolphins will follow fishing boats, as they hope to catch escaped fish.”

However, Mr. Parsons said that, as there is no law limiting the size of fishing nets and the species captured, fewer fishes will be available for the dolphins.

Moreover, the construction of the new airport at Chek Lap Kok is destroying the natural habitat there. The Chinese white dolphins are in danger of extinction.

Mr. Parsons said, “The extensive reclamation for the airport platform destroys the shallow areas on the coast of Lantau Island. Therefore, the dolphins may be forced to leave.”

The World Wide Fund of Hong Kong states that the strong tidal waves transmitted from blasting at the new airport construction site damages the lungs of the dolphins. The subsequent internal bleeding could kill the dolphins.

The blast may also be strong enough to deafen the dolphins or interfere with their sonar capabilities, which are the ways they use to communicate, to search food and to escape from obstacles. This also may cause the death of dolphins.

Sewage from Discovery Bay will be sent to the proposed sewage outfall for the airport and the new town of Tung Chung. However, the sewage may contain toxic chemicals and it will disperse directly into the marine environment, which will harm the dolphins.

Mr. Chan said, “A marine sanctuary is proposed to be built in the area around Lung Kwu Chau and Sha Chau in order to protect the marine life. This would be about 120 hectares in size.”

However, according to Mr. Parsons, the sanctuary is supposed to be built beside a fuel barge depot at Sha Chau.

Said Mr. Parsons: “It seems to be an absurd idea to put a sanctuary next to a fuel barge depot which will certainly harm the dolphins and drive them away.”

Moreover, Mr. Chan Yiu Keung, a conservation officer of the Port and Airport Development of the Agriculture and Fisheries Department, said that the study of the Chinese white dolphin is insufficient. The department has very limited information exchange with other countries.

“However, our department has asked the Hong Kong Swire Institute of Marine Life of the University of Hong Kong to conduct a research programmes on Romer’s tree frogs and the Chinese white dolphins,” said Mr. Chan.

The research started in 1993 and is supposed to be finished in the late 1996.

A way to protect these valuable creatures is legislation.

Miss Leeanne Nuttall, 21, of Kennedy Town, said, “I believe there is no current policy concerning the saving of Chinese white dolphins at all.

“However, they are important members in the ecosystem. I like them. They are intelligent and friendly.”

According to Mr. Chan, there is the Wild Animal Protection Ordinance which protects the Chinese white dolphin and the Romer’s tree frog from being hunted, caught, killed and sold.

Mr. Bill Leverett, person-in-charge of Hong Kong Dolphinwatch, which organizes a Chinese white dolphin watching tour, said, “Even if there are laws to protect the dolphins, usually they are not strictly enforced.

“Hong Kong people care only about money. I am disappointed that most of the participants in the tours are foreigners,” said Mr. Leverett.

If the Hong Kong’s natural environment continues to be destroyed, more of the Territory’s wildlife will suffer the same fate as the Romer’s tree frog and the Chinese white dolphin, states the World Wide Fund.

February 1996