INTERESTING OBSERVATIONS ON SEA TURTLES FROM THE CHENNAI COAST OF INDIA IN 2016
ARUN V1, # & ADHITH SWAMINATHAN1,2
1Students’ Sea Turtle Conservation Network, Chennai, Tamil Nadu, India
2Dakshin Foundation, Bangalore, Karnataka, India
#arun.turtle@gmail.com
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STRANDINGS
This season (January to April 2016) was marked by the stranding of juvenile turtles of sizes that are uncommon along the coast of Chennai, India. Two olive ridley, one green, and one hawksbill turtle (Table 1) were observed stranded between the months of February and May in the 7km stretch of beach from Neelankarai to the Adyar River estuary that is patrolled daily during the nesting season. Three of the four stranded turtles were dead when found. The olive ridley turtle found on 27 February 2016 was barely alive and coated with a greasy material. The turtle was taken to the TREE Foundation rescue centre at Neelangarai, Chennai, for treatment, where it later died despite efforts to resuscitate it. The green turtle found on 17 May 2016 was observed by one of the authors during a casual walk on the beach after the nesting season had ended.
There is limited information available about the juvenile life stage of olive ridley turtles as they are completely oceanic (Bolten, 2002), therefore these observations generated much interest. In the last decade, there have been several reports in the local media and anecdotal observations of juvenile olive ridley, hawksbill and green turtles being stranded and entangled in fishing nets (Nina Simon, 2010; Frederick, 2011; Special Correspondent, 2011; Oppili, 2015; Special Correspondent, 2016). However, there are no detailed reports on the size of these turtles and, therefore, the term juvenile could have been inappropriately applied.
Pseudonesting
During an organized public walk on 26 March 2016, an olive ridley turtle (CCL- 63cm, CCW- 62cm) was observed making a body pit, digging a nest cavity, and camouflaging the site. Care was taken to not disturb the turtle during the entire duration of the nesting process. Once the turtle returned to the sea, the volunteers probed the sand to relocate the nest to a hatchery. However, only a well-formed nest chamber was observed with no eggs. The entire camouflaged area was dug up and searched thoroughly for two hours. It was then concluded that it was a pseudonesting event. This was the first observation of such a phenomenon in Chennai, although Swaminathan & John (2011) have reported similar behaviour in olive ridley turtles at Rushikulya, Orissa. Such behaviour is not uncommon in primigravid turtles (those laying their first clutch) and may be due to limited oviductal responsiveness to hormonal stimuli and/or motility at the first nesting attempt (Phillott, pers.comm.).
Literature cited:
Bolten, A. B. 2002. Variation in sea turtle life history patterns: Neritic vs oceanic developmental stages. In: The Biology of Sea Turtles, Volume II. (eds. Lutz, P.L., J.A. Musick & J. Wyneken). Pp 243-257. CRC Press, Boca Raton, USA.
Frederick, P. 2011 (June 16th). Ridleys! Believe it or not. The Hindu. Retrieved from: https://www.thehindu.com/features/metroplus/ridleys-believe-it-or-not/article2110163.ece.
Oppili, P. 2015 (August 23rd). Entangled green turtle rescued, released in to sea off Chennai coast. The Times of India. Retrieved from: http://timesofindia.com/city/chennai/Entangled-green-turtle-rescued-released-in-to-sea-off-Chennai-coast/articleshow/48642413.cms.
Simon, N. 2010 (September 1). Greenie goes home. The Hindu. Retrieved from: https://www.thehindu.com/features/metroplus/nxg/greenie-goes-home/article607237.ece.
Special Correspondent. 2011 (March 11). Sea turtles rescued. The Hindu. Retrieved from: https://www.thehindu.com/todays-paper/tp-national/tp-tamilnadu/sea-turtles-rescued/article1528211.ece.
Special Correspondent. 2016 (April 24th). Two stranded green turtles rehabilitated, released into sea. The New Indian Express. Retrieved from: https://www.newindianexpress.com/cities/chennai/Two-Stranded-Green-Turtles-Rehabilitated-Released-into-Sea/2016/04/24/article3397245.ece.
Swaminathan, A. & S. John. 2011. Pseudonesting behaviour by the olive ridley sea turtle Lepidochelys olivacea (Eschscholtz, 1829) during mass nesting at Rushikulya, Orissa, India. Herpetology Notes 4: 225-227.