SATELLITE TRACKING FOR LOGGERHEAD TURTLES, CARETTA CARETTA: NOTE ON NAVIGATIONAL ABILITY IN THE OCEAN

Abstract

An adult female (104 kg) loggerhead turtle Caretta caretta was released and tracked with satellite transmitter after 10 years of keeping and rearing in captivity of Mannai Island Sea Turtle Conservation Station, Thailand. In 1992, she was inccidentally caught by small-scale gill net near the Mannai Island Station at 80 kg in body weight. Since having new freedom in the wild on 1st of July 2002, she immediately headed southeastward across the Gulf of Thailand for neighboring country's water. The transmission reported her journey passing over Malaysia Peninsula, South Borneo Island and Bali Sea of Indonesia until the signal ended at Coast of Derby City, Western Australia. The turtle could swim at nearly steady speed in a range of 1.3-2.6 km/h from original to the last position in 135 days with an accumulation distance of 4, 309 km. The results of her genetic maker also revealed that her genotype was the same as Australian turtle. Although the loggerhead had long been kept in captivity, she still made travelling in quite straight line to foraging area with cruising speed nearly the same as the natural turtles. This evidence supports hypothesis of strong efficiency movement in navigational ability of sea turtle in the ocean.