Yellow River ecology in peril

Environmental experts told the Global Times Sunday that exotic aquatic species released into the Yellow River could have destroyed parts of local ecosystems.

It came after a report from authorities in Shandong Province who said that "mercy releases," when well-meaning but misguided animal lovers release fish and reptiles into waterways, are to blame for harming the river's aquatic ecosystem.

"Over the past years, many exotic species, including red-eared sliders (turtles), have been set free, which risks the already-fragile ecosystem of the Yellow River," reads the report issued on the website of the Shandong Oceanic and Fishery Department.

According to statistics from seven survey spots along the river, exotic carp and catfish have settled in the downstream of the river, while bullfrogs and red-eared sliders, as two of the 100 most invasive species listed by the International Union for Conservation of Nature, take up a large proportion of catches by local fishermen.

Snapping turtles, often referred to as the "eco-murderers," are also frequently spotted in the area.

Zhao Xinru, a professor of zoology at Beijing Normal University, told the Global Times that the balance of the local ecosystem can be theoretically broken down by the invasion of these species.

"The animals, especially the turtles, usually consume more food because they are highly adaptable and more efficient as predators," Zhao said, adding that bullfrogs can cause extinction of the local frogs because of their fierce predation and strong reproductive ability.

Many Buddhists in China practice "mercy release" as an affirmation of mercy and treasuring life. The released animals usually include fish, turtles and snakes.

Wang Yucheng, a Beijing Resident who used to own a snapping turtle, confessed he had set his pet free years ago without any knowledge of the damage it could do.

"There is the rule of the survival of the fittest, right? I thought other animals could manage to survive in their own way," Wang said.

Zhao noted that as turtles are popular in pet markets, they are the most commonly freed animal. "However, they are more hazardous, because they are omnivores and sometimes fierce predators. Their long lives also make their damage more serious."

Although the report urged that freeing exotic species must be banned in the Yellow River, Zhao noted that this will be hard to achieve as there is a lack of laws and supervision.

"At present, we can only raise public awareness of science through education. People need to realize that it is harmful to the environment if they set those animals free. That's the only way they'll regulate themselves," Zhao said.