Scientists have introduced measures to wipe out invasive red-eared turtles that are threatening endangered local species, including Hoan Kiem Lake's giant turtle linked to legendary Kim Qui the Turtle.
The giant species, one of a handful of giant Red River soft-shelled turtles (Rafetus swinhoei or Rafetus leloi) left in the world, has been around at least since the third century BC when Kim Quy advised King An Duong Vuong on the best way to build defensive walls around Co Loa, the then capital, upstream from Hanoi.
According to Professor Nguyen Dinh Hoe from Hanoi National University, red-eared sliders (Trachemys scripta elegans) are alien species from the southern United States that cause terrible devastation.
They are said to eat any type of vegetation or meat, even if it is stale and rotten. "This type of food can even be used to catch them," said Hoe.
Professor Dang Huy Huynh, chairman of Vietnam Zoological Association and Doctor Nguyen Van Sang from the Institute of Ecology and Biological Resources believe manual methods would be the best way to try and clear the invaders from the Hoan Kiem Lake.
Huynh recommended that small sand dunes be created along the lake shore to lure red-eared turtles to sunbathe and lay eggs.
He also called on people living near the lake to catch and destroy red-eared sliders whenever they see them.
Scientists have devised ways to wipe out the pests, especially as Tet (lunar new year) is approaching and many more red-eared sliders will be set free into the lake, ostensibly to earn merit.
Hoang Van Ha from the Asian Turtle Program said it would be best to use lay traps near the lake shore to catch the invaders. He said the traps would be very small to avoid causing any harm to the ancient Vietnamese turtle.
Amid the horn-honking hustle of Vietnam's capital, the Hoan Kiem Lake is an oasis of relative calm. It attracts tourists and locals alike, the luckiest of whom occasionally catch a glimpse of "the turtle," the most famous resident of the capital.
Turtles are important in Vietnamese culture, particularly the Ho Guom (Hoan Kiem) turtle. It is so rare it is believed only four may be left in the world. Legend has it that after beating a Chinese invasion with a sacred sword found in Hoan Kiem Lake by a fisherman, King Le Loi handed it back to Kim Quy the turtle. In fact, in Vietnamese, the name of the lake means "Returning Sword."
Professor Huynh warned that invasions by red-eared sliders were worrying environmentalists in many countries. In 1990, France and several other European countries made it illegal to buy and sell the reptiles.
The professor said Vietnam's laws and regulations on managing the invasion of alien creatures were poorly implemented. This meant that even if the pests were cleaned out, it is likely they would soon re-appear with the help of ignorant citizens.
The golden snail, for example, imported to Vietnam about 10 years ago, has withered rice in many Cuu Long (Mekong) Delta provinces. The species is now spreading to the central region and the north of Vietnam.
Golden snails lower rice production and hundreds of million of dongs have to be spent on battling them every year – with poor results.
Red-eared sliders, which are native to the southern United States, began appearing in Vietnam 10 years ago as children's pets. They can live to 70 years and are ranked as one of the most invasive species in the world.
A Mekong Delta seafood company that imported 40 tons of invasive red-eared slider turtles has asked a local court to make the US exporter take back or destroy the creatures.