In Southeast Asia virtually all knowledge about sea turtle biology is derived via nesting beach studies. This study investigated life-stage parameters for a foraging population of immature green turtles Chelonia mydas off the coast of Borneo, Malaysia, to elucidate a significant portion of the at-sea lifestage component. Mark-recapture provided new data on localised movements between captures, growth data, and residency period. Turtles moved only an average of 380 m between recaptures, and shared site-fidelity over several recaptures spanning up to two years. Size classes suggested all animas were juveniles, and ranged from 38 to 80 cm CCL. Growth rates amongst these averaged 3.6 cm•yr^-1. Laparoscopic examinations of the gonads confirmed that all individuals were immature, with a sex ratio of 1 M : 4 F. These initial data on foraging C. mydas population structure and dynamics are of use for life-stage population models and turtle management and recovery planning.

Given what scientists presently know about sea turtles, there are some crucial gaps that have the potential to undermine management efforts. Among these is the knowledge of how many turtles join the breeding population in any given year, the period between onshore migration of juveniles to adulthood, and natural sex ratios in the wild. Lack of a clear understanding of any of these can have an effect on how turtle population data is interpreted and how this results in conservation action. While it is easy to count how many baby turtles leave a nesting beach, and how many adults return to nest, it is often unknown what happens in the time periods in between, and these periods often last some 25-30 years. Having an understanding of what happens in between, and knowing recruitment to adult breeding populations can help managers determine conservation needs.

Frustratingly for biologists and managers attempting to influence how turtle populations will be affected by various natural and anthropogenic stresses, there is practically no way to determine what proportion new entrants to the breeding population represent, and whether there is a long-term decline in recruits or the reverse. These data are crucial and among the top priorities for researchers at present time, and this project would assist in providing the data sets to complement the long-standing history of research and data gathering from Sabah, and can be determined through the use of laparoscopy studies.

 

“Laparoscopy is a form of surgery that uses a miniature telescope to directly view the inside of the peritoneal cavity. It is a potentially dangerous procedure and must not be attempted until proper veterinary training has been obtained. Laparoscopy can be used to determine the sex of immature turtles or the reproductive status of adults.”

 

The project has built capacity at the local level to carry out the delicate surgical procedures, using laparoscopy, to identify sea turtle gender and reproductive status, and use these data to contribute to effective management regimes at key SE Asian turtle rookeries. The project involved training MRF staff and a member of the Sabah Parks scientific staff on laparoscopic techniques and interpretation with Dr. Colin Limpus (Queensland Parks and Wildlife Service, Australia), providing the equipment to carry out the studies in Sabah, Malaysia, and to implementing laparoscopy studies on green and hawksbill turtles in Sabah.

 

To see a brief slideshow of one of our turtle catching and laparoscopy adventures, please click the image or here: