VOA慢速英语:湄公河上的伊洛瓦底江海豚数量在增加

The number of Irrawaddy dolphins in one part of the Mekong River has increased for the first time tin 20 years.

The dolphins, however, still face serious threats to their survival. They are considered critically endangered marine mammals in their native Southeast Asia.

The Cambodian government and a major wildlife group reported the population increase earlier this week.

Cambodia's Fisheries Administration and the World Wildlife Fund (WWF) released results of a 2017 count of freshwater dolphins along a 190-kilometer part of the Mekong. The survey area stretches from Kratie in Cambodia to the Khone Falls in Laos. Observers reported finding about 90 dolphins. That is a 15 percent increase over an estimate of 80 made in 2015.

The dolphins are found in only two other freshwater rivers: the Irrawaddy River in Myanmar and the Mahakam River on the Indonesian part of Borneo Island.

Eng Cheasan is the director-general of Cambodia's Fisheries Administration. He described the dolphins as a "living national treasure." He added that efforts to save the rare animals would continue.

"We will continue our conservation efforts to rebuild its population by eliminating all threats to the survival of the species," he said.

Although the increase during the latest count is good news, the number reported in the Mekong is only half of the 200 found during the first population count in 1997. Surveys are carried out every two to three years.

Seng Teak is the WWF director for Cambodia. He told reporters in Phnom Penh that the dolphins still face threats from illegal fishing methods, increasing boat traffic and new dam projects.

He said the biggest threat for the marine mammals is to get caught in gillnets, large traps which are held in place through the use of floats and weights.

Seng Teak said several thousand meters of illegal fishing nets had been seized and many fishermen arrested.

The most recent survey showed hopeful signs for the long-term survival of the dolphins. More baby dolphins, called calves, have been reported and deaths are down. The study found that 32 dolphins have been born in the area during the past three years.

Seng Teak said efforts by the WWF, the government, the tourism industries and local communities have made a difference.

"After years of hard work, we finally have reason to believe that these iconic dolphins can be protected against extinction," he said.

The WWF says the dolphin is an important sign of the health of the Mekong River environment. Dolphin watching and ecotourism is an important business for communities on the river. Some people living in Cambodia and Laos consider the animals holy.

I'm Mario Ritter.

Mario Ritter adapted this AP story for VOA Learning English with additional material from the WWF. George Grow was the editor.