Japan turtle finds haven in Taiwan

by Ko Shu-Ling

Kyodo

In late January, Cheng I-Jiunn, a marine biology professor at the National Taiwan Ocean University, got a call telling him a green sea turtle incidentally captured in the northeastern part of the island desperately needed medical attention.

A titanium tag installed on the turtle identified it as a 40-year-old green sea turtle from Hirashima Island, one of two in the Bonin Island chain — part of the Ogasawara Islands — where beaches are set aside for nesting, Yoshimasa Matsuzawa of the Sea Turtle Association of Japan said.

The turtle, dubbed Lady Gaga by Cheng and his students, was far from its regular feeding grounds that stretch from the coastal waters of the Kanto region south as far as the Ryukyu Archipelago.

She was very lucky.

Doctors found it had swallowed plastic bags, a balloon and other indigestible materials. She had also sustained shark bites, possibly while it was floating too weak to swim.

Thousands of turtles are killed every year as they navigate the increasingly dangerous waters of the Western Pacific seeking food and nesting grounds.

The region’s green sea turtles are being pushed toward extinction by hunting, egg harvesting, pollution, destruction of habitat and injuries from passing ships.

Because of these dangers, Cheng approached Taiwan’s legislature in 1992 asking the lawmaking body to protect the endangered species.

Three years later, the Penghu County Government designated six beaches on the western and southern parts of Wangan Island in the Strait of Taiwan as protected areas. It went a step further in 2002 to establish the Green Turtle Tourism and Conservation Center.

Each year during breeding season, Cheng leads a team of students to work at the Wangan sanctuary. A typical task is to dig out new hatchlings on the protected beaches.

One Sunday afternoon in late July, Cheng and his students found the eggs in one nest three days overdue with signs that a snake had disturbed them. After carefully excavating the nest, they saw one hatchling emerge, then another and another.

The mother turtle had laid 93 eggs. Four were eaten by the snake, six did not hatch and one young turtle died soon after hatching. But the rest were healthy.

Cheng and his students then took the hatchlings to his nearby workstation for measurement. Each weighed about 24 grams and measured 47 cm long and 5 cm wide. They can grow up to 90 to 120 cm long and weigh more than 100 kg.

After measurements are taken, new hatchlings are released into the sea. Normally, the process of moving from the nest into the water is the most dangerous time in a turtle’s life.

But on that afternoon, all made it except one who lagged behind, possibly disoriented from the heat or reluctant to leave its human caretaker.

Apart from human factors, green turtles’ breeding is irregular. It takes about 20 to 50 years for a green turtle to reach sexual maturity. Mature females usually return to the beach from which they hatched every two to five years. Studies show that only 5 percent of them chose beaches different from their hatching ground.

When they do that, a female green turtle lays an average of 100 eggs in each nest and does so three or four times with a two-week interval. It usually takes about 50 days for the eggs to hatch but only 65 to 80 percent of the hatching is successful. Among them, only 1 in 1,000 makes it to maturity.

While land turtles can live to 140 to 200 years, green sea turtles that reach maturity may live to 80 in the wild.

In the Wangan sanctuary, between four and 19 green turtles return to their hatching ground to lay eggs each year between June and September. During the breeding season, visitors are banned from entering the beaches between 8 p.m. and 5 a.m.

Satellite tracking installed on green turtles hatched in Wangan shows that they migrate as far as Kyushu and China’s island province of Hainan in the South China Sea.

While those traveling to Japan make it back safe and sound during the breeding season, many of those passing China are caught, some sold for skin and others eaten, Cheng said.

It was pure accident when Cheng threw himself into the conservation effort for green turtles in 1992. At that time, he did not have any graduate students and one student working on green turtles in his department did not have an adviser.

So he signed up for the job, and has never looked back. Lady Gaga returned to the sea on April 2.

Cheng said he hopes humans will change their behavior, reducing the amount of litter that pollutes her ocean habitat and protecting her species for future generations.