An annual ceremony to celebrate the Queen of Thailand's birthday has been marked by the release of 779 green turtles.

The turtles were released from the Royal Thai Navy's Sea Turtle Conservation Centre in the Sattahip naval base as a token of gratitude to Queen Sirikit who turns 78-years-old on Thursday.

Most of the turtles are three to six months old, while seven are adults aged between six and 16 years old. The adult turtles have been fitted with microchips for conservation research.

Some 300 officials, conservationists and students take part in the event each year to watch the young turtles born and raised in the conservation centre swim off to sea.

About 10,000 young turtles are released from this centre to the Gulf of Thailand every year.

Statistics from the conservation centre said the survival rates of the small turtles released into the Gulf of Thailand has increased over the past decade.