Sea water temperature tests to see impact on turtle population

From an article by Apinya Wipatayotin in the Bangkok Post as posted on Ocean Conserve:

The Marine and Coastal Resources Department is monitoring sea water temperatures at five major turtle nesting grounds to study the impact of global warming on their population. The targeted areas are Koh Surin, the Similan islands, Tai Maung beach and Prathong beach in Phangnga, and Koh Kram in Chon Buri province.

The move comes after international marine biologists recently found evidence that a rise of just one degree Celsius in sea water temperatures can stop the development of male turtles.

Unlike mammals, including humans, where sex determination is chromosomal, turtles' and crocodiles' sex is determined by genes which react to the temperature during the incubation stage of their eggs.

Marine biologist Kongkiat Kittiwattanawong, of the Phuket Marine Biological Centre, said the optimum temperature for turtle hatching is 29.5C.

''Only at this temperature can we hope to see the same number of male and female turtles hatch in the same nest.''

A study of the impact of rising sea temperatures on sea turtles in Malaysia suggested that the warmer climate has led to a sharp reduction in the male sea turtle population, said Mr Kongkiat.

As a result, fewer female turtles come to nest.