Constellation of the comb-turtles that reproduce in Rio Grande do Norte
Historically, the vast majority of studies with sea turtles are on spawning beaches, with females and their offspring. Until the 1980s, information about the dispersion of these animals in the immensity of the ocean was limited to rare recaptures outside the marking site. The development of molecular techniques from the 1990s has led to an explosion of genetic evidence about the fidelity to the natal site and also about the diversity of origins found in the feeding areas.
With the advent of the new technological age and development of ever smaller tracking devices, unprecedented advances have been achieved in the knowledge of migratory routes, ecology and behavior in general.
Most aquatic telemetry studies use acoustic approach or satellite telemetry. The animals marked by acoustics are detected by fixed receivers (stations) or mobile, while in satellite telemetry the information is sent to satellites in orbit and relayed to a ground base where the most used system for tracking fauna from the poles to the tropical areas is the French Argos system.
In Brazil, the technology began to be used in 2000 to study the displacement of juveniles and adults of green turtle in Ceará. Since then, studies have been developed to track breeding females of turtle-headed turtle and turtle in Bahia, olive turtle in Sergipe and leather turtle in Espírito Santo.
In Rio Grande do Norte, the tracking of turtles was initiated in 2015, the result of a licensing constraint for seismic research. The research was dubbed the "Constellation of the Turtles-of-Pente" and each turtle was named after a star seen in the sky at the time the female is spotted. In the first stage, 12 transmitters were coupled between February and June 2015. Two types are being used; the first (SPOT5) is limited to the geographical position with an accuracy of about 350 meters. The second (SPLASH10), besides the position, also has sensors of temperature and depth, recording the time of diving and surface of the turtle. In case of a recapture of the animal, it is possible to download all the data stored in an internal memory. These recaptures allow you to collect an incredibly complete, GPS-accurate data packet and record each dive during the programming period.
It was possible to recapture five females and download within 15 days between one posture and another. Although preliminary some behaviors have already been observed as the displacement of 2 days soon after spawn until reaching the point of "rest." When she finds her place of refuge, she resides for about 11 days with dives of up to 40 meters with a longer duration. After this period, the turtle begins the return trip to the spawning beach. Again, you will return to shallower and shorter dives where surface times increase during this period. This fact must be related to the visualization of the beach before deciding the exact point of ascent to the beach to spawn.
Of the 12 trawled turtles in 2015, two have lost their signal before reaching their feeding sites; however for the other ten it was possible to identify the stopping point after the post-reproductive migration began. The turtle baptized Capella, did not migrate moving only 19 km remaining in the vicinity. Two females settled in Maranhão, with Mimosa (1513 km) and Alfa Centauri (1175 km). Three females settled along the Ceará coast at distances ranging from 365 to 730 km from the spawning beach. Two females settled in Paraíba, at distances of 84 and 131 km from the spawning beach. The female Antares descended to Alagoas, where it found its feeding area 274 km from the spawning beach. The female Atria migrated to the north (103 km) but did not come to leave of water potiguares. This female catches attention because it is an animal that was caught as a cub, raised for five years in captivity in the house of a fisherman and then released to the sea in 2005. Ten years later she was seen spawning on the same beach where she was born, known as Eye of the Water, in Baía Formosa-RN.
This information is related to the first stage of the research that follows during this spawning season where 18 more transmitters should be coupled. The information generated may one day be used for future conservation strategies of the critically endangered Turtle on its migratory routes.
By Daniel Henrique Gil. Original text published in Revista Bora - Edição 16 - May / Jun 2016