Lamma turtle tracked to Hainan

PUBLISHED : Sunday, 10 November, 2002, 12:00am
UPDATED : Sunday, 10 November, 2002, 12:00am

The mystery of Lamma's migrating green turtles has become clearer after a satellite device was used to track one more than 500km to feeding grounds off Hainan Island.

The endangered species is known to swim thousands of kilometres to return to the beach where they were born to lay eggs - but the location of the feeding grounds of the turtles that nest at Sham Wan, Lamma, has never been known until now.

Conservationists put a transmitter on the shell of a female turtle that laid eggs on August 9. They then tracked her 20-day journey as she swam towards Hainan Island at between 500m and 2km an hour.

An officer at the Agriculture, Fisheries and Conservation Department, Simon Chan Kin-fung, said officials would continue the tracking until the transmitter fell off the turtle's shell or its battery ran out.

'Signals from the transmitter indicate that the green turtle usually dives for 15 to 30 minutes to eat sea grass and seaweed and surfaces to breathe before the next dive,' he said.

'The green turtle is expected to stay in the feeding ground and may come back to nest in Sham Wan three to five years later.'

The green turtles which breed on Lamma are survivors of an era when turtle eggs were eaten by villagers, who regarded them as a nutritious aphrodisiac.

The turtles and their ping pong ball-sized eggs are now protected by law, and Sham Wan - which is the only turtle breeding ground in Hong Kong - is closed to the public during the breeding season from June to October.

Decades ago, turtles used to nest regularly on other beaches in Hong Kong, including at Tung O and Ha Mei Wan on Lamma; Tong Fuk Miu Wan and Tai Long Wan on Lantau; and Tai Tam Bay.

It is unclear how many green turtles are left in the world, because they spend most of their time in the water, but the number of turtle eggs counted internationally has dropped drastically.

About 500 green turtle eggs in six clutches hatched naturally at Sham Wan this year.

Last year the department helped mainland counterparts track three green turtles at Gangkou National Nature Reserve, Guangdong, finding that two travelled to Hainan Island and one to Okinawa, Japan.