Distribution : Tamil Nadu and Puducherry

Nesting species:

Non-nesting species: green, leatherback, loggerhead, hawksbill

Overview

Tamil Nadu has a coastline of 1076 km (excluding the Union Territory of Pondicherry), which is largely East-facing with a small stretch of West-facing coast (80 km). Five species of marine turtles — olive ridley, green, leatherback, hawksbill and loggerhead turtles — have been reported to occur along the Tamil Nadu coast (Kar and Bhaskar 1982). Olive ridley turtles nest along the Coromandel Coast and are known to forage in southern Tamil Nadu waters. Nesting by other species is rare if present at all. Large numbers of green turtles once used the Gulf of Mannar for foraging but these numbers have declined due to exploitation for meat (Agastheesapillai and Thiagarajan 1979, (Bhupathy and Saravanan 2006). Hawksbill turtles are also found in the Gulf of Mannar and stray adults and juveniles are occasionally seen along the rest of the coast. Similarly, leatherbacks are occasionally seen along this coast. Loggerhead turtles are rare and there are few confirmed reports, but they are known from Sri Lankan waters and may be found in the Gulf of Mannar. This coast forms a part of the migratory corridor for olive ridleys en route to the mass nesting beaches in Odisha. Mortality of thousands of olive ridleys has been reported in Odisha due to incidental catch in fishing gear and several hundred are killed along the Tamil Nadu coast as well (Pandav 2000). Hence, there is considerable concern about the deterioration of nesting habitats and feeding areas in Tamil Nadu.

In southern Tamil Nadu, all the sea turtles have several common names. The Ridley is known as yeth aamai (turtle that comes up), panchal aamai (after a village near Kanyakumari), and vakatta aamai (poor turtle, probably for the small amount of meat). The green is known as perunthalai aamai (large headed turtle), then aamai (honey turtle), panguni aamai (after the Tamil calendar month in March-April) and per aamai (large turtle). The hawksbill is called yeli or yelithalai aamai (rat or rat-headed turtle), alungu aamai (pangolin turtle), kili mooku aamai and (parakeet beaked turtle). As for the leatherback, it is compared to dolphins (oongal aamai), as well as to pigs (panni aamai), and for those who know this animal, that is actually good symbolic representation of their grace in the water and lack of it on land. It is also known as the elzhuvari aamai (seven line turtle), ooduvetti aamai (after the powerful flippers that can injure a person), and elsewhere on the coast as thoni aamai (bullock cart wheel turtle). One could infer from these various names that interactions with these species were extensive in this part of the country

History

Madras has a special place in the history of sea turtle conservation in India. It is one of the first locations where sea turtles caught the attention of biologists and conservationists (the other being Odisha). As part of the Madras Snake Park, Rom Whitaker had started turtle walks to count and protect nests on the Madras coast. In 1974, they started the first hatchery in the backyard of a friend’s house on the beach.  Many ecologists and conservationists – Satish Bhaskar, Anne and Preston Ahimaz, Shekar Dattatri, Kartik Shanker, Sanjeev Gopal, Adhith Swaminathan – were keenly involved with turtle walks early in their careers. One of them (Adhith) started out as a 10-year-old in 1996 and is now writing this chapter.

 Sea turtles have been documented on the Tamil Nadu coast for a long time due to turtle fishery in the Gulf of Mannar. Some of the earliest accounts of sea turtles in India come from this region. The oldest known reference to marine turtles is a poem from the Tamil Sangam literature (c. 400 AD) in which the egg laying of marine turtles is described (Sanjeeva Raj 1958).

The Chennai coast, in particular, has been monitored by various organisations. Research and conservation of marine turtles on the Chennai coast was initiated by a group of naturalists led by Romulus Whitaker in the early 1970s. It was one of the first such efforts in the country, and in fact, amongst the early conservation programmes worldwide. The Madras Snake Park Trust (MSPT) maintained a sea turtle hatchery from 1974 – 1976, following which the Central Marine Fisheries Research Institute (CMFRI) maintained a hatchery for several years and conducted research on various aspects of marine turtle biology and fishery-related turtle mortality. The Tamil Nadu Forest Department maintained several hatcheries along the Coromandel coast through the 1980s, and World Wildlife Fund (WWF) was involved in conducting ‘turtle walks’ during that period. The Students Sea Turtle Conservation Network (SSTCN) has maintained a hatchery and monitored this coast annually since 1988 and conducted ‘turtle walks’ for the public. The Madras Crocodile Bank Trust (MCBT) has also been involved in monitoring the beaches south of Chennai. Most recently, the TREE Foundation has been involved in community-based conservation of sea turtles involving fishing youth from the villages in and around Chennai.

Not much is known about the biology of sea turtles in the Gulf of Mannar, even though Krusadai Island has long been called a biologist’s paradise and one of the first accounts of sea turtles is Chacko’s 1943 description of a ridley on this island in the journal Current Science (Chacko 1942). In March 1977, Satish Bhaskar visited the Gulf of Mannar to survey the status of sea turtles. This was, in fact, his first survey. Visiting Krusadai, Hare, Pullivasal and a few other islands, he sighted a few dugongs and green turtle and ridley carapaces. Later visits would confirm the presence of green turtles in large numbers and the exploitation of both greens and hawksbills (Bhaskar 1981).

There does appear to have been a fair amount of interest in sea turtles at the Mandapam research station of CMFRI through the 1970s and 1980s. Agastheepillai and Thiagarajan provide an account of the biology of green turtles in the Gulf of Mannar, based on turtles caught during 1971 to 1976.

Research

In 1974, Valliapan and Whitaker conducted a survey in the winter of 1973-74 along a 50 km stretch from Marina-Madras to Kalpakkam (currently the site of a nuclear power plant). During this survey, they found lots of depredated nests (over 40 on one night covering about 10 km), and 17 dead turtles over the course of the season. Fishers told them that the turtles were ‘caught and drowned during the dragging of nets by steam launches’. Both Valliapan and Whitaker, and later Bhaskar, estimated the number of nests at about 100 per km per season along this coast (Valliappan and Whitaker 1974, Whitaker 1977, Bhaskar 1981). The SSTCN collected about 50 to 200 nests per season over roughly 10 km during the 1990s and 2000s, indicating that the abundance was in the range of 5 to 15 nests per km per season near Chennai, the northern part of the TN coast (Shanker 2003).

In 1998, Banugopan, a master’s student of  Ecology at Pondicherry University, conducted a survey of the Pondicherry coast; only 5 nests were recorded over a 3 km stretch but 54 dead turtles were counted (Banugopan and Davidar 1998). Banugopan would go on to work with Pandav in Odisha, maintaining his Rushikulya camp during 1999.

In 2001, S. Bhupathy of the Salim Ali Centre for Ornithology and Natural History (SACON), in Coimbatore, undertook a systematic survey of sea turtles on the Tamil Nadu coast as part of the GOI-UNDP project, followed by another survey under the UNEP-CMS project. During the first project, they surveyed over 800 km of the Tamil Nadu coastline and found about 500 km of sandy beaches, with the potential for nesting.  They identified the coastline between Tranquebar and Pazhaiyar (Nagapattinam district) and Pondicherry and Chennai as the most important nesting areas on the TN coast (Bhupathy and Saravanan 2006). 

Along the latter stretch of the coast, they estimated 10 nests per km per season, which is comparable to the numbers collected by SSTCN during this period. Bhupathy’s survey for the UNEP-CMS project in 2004 was carried out in the field by J. Subramanean, a long-time SSTCN volunteer, as part of his master’s dissertation in Pondicherry University. In their paper in Hamadryad, Bhupathy, Subramanean and Vijay recorded 134 dead olive ridley turtles and 5 green turtles and again, the nesting density was estimated at about 10 nests per km per season. Many of these nests were depredated, but few by humans, indicating that conservation activities in this region had reduced egg collection. In addition, they found that nest densities were correlated with distances from river mouths and negatively correlated with distance from villages, providing more support for the notion that ridleys like river mouths.

Bhupathy’s 2001 survey along the Nagapattinam coast indicated a nesting density of about 20 nests per km. They estimated a total of about 1000 nests per season along this coast (50 km). They encountered about 70 nests, most predated by humans and a few by dogs and jackals. They also counted over 200 dead turtles, mostly ridleys but several green turtles as well (over 400 dead turtles were counted along the entire TN coast). Most of the turtles had visible injuries, with heads or flippers missing, indicating that they were caught in gill nets (Bhupathy and Karunakaran 2003). In their 2003-04 survey, they estimated slightly lower densities of 10 to 15 nests per km along this coast (and counted about 90 dead turtles). About 20 dead turtles were observed the following year in December, and none the rest of the season as fishing stopped for several months in the aftermath of the December 2004 tsunami. Based on Bhupathy’s surveys and other data indicating an average density of about 10 to 20 nests per km on this coast, one can estimate that the Coromandel coast of Tamil Nadu, between Chennai and Point Calimere (~ 300 km), gets about 3000 to 5000 olive ridley nests per year.

SACON’s surveys also revealed that the exploitation of adult turtle continued illegally on the southern Tamil Nadu coast, though the proportion of different species in the catch had changed over the decades. Where green turtles had once formed the bulk of the catch in the 1960s, olive ridleys were a third or half of the catch by the 2000s (Bhupathy and Saravanan 2006). Bhupathy and others also found ridley turtles which had been tagged in Odisha, indicating that at least some of the turtles which nested in Odisha were using the Gulf of Mannar as their feeding ground (Bhupathy and Saravanan 2006).

Subramanean followed this up with a survey in early 2005 following the tsunami in December 2004. Along a 5 km stretch of the Chennai coast, 65 nests were recorded during the season, suggesting that the tsunami had little impact on nesting along this coast (Subramanean 2005).

Long-term data for the Tamil Nadu coast comes from the hatchery programmes conducted by various organisations on the Chennai coast. While there is a considerable inter-annual fluctuation (between 20 to 200+ nests per season on a 7 km stretch), recent records indicate nesting abundance including on stretches of beach where nesting was not previously recorded.

Conservation

The main threats to sea turtles are incidental catch in fishing nets, depredation of eggs by feral predators (mainly dogs), and coastal development. Depredation of eggs is widespread and only mitigated by conservation programmes on the northern Tamil Nadu coast. Coastal development through ports, harbours and sea walls leads to erosion and the loss of nesting beaches. In addition, extensive plantation of Casuarinas has led to erosion and decline in nesting beach availability. Finally, coastal development comes with light pollution which leads to the disorientation of adult nesting turtles, and the disorientation and mortality of significant numbers of hatchlings.

Incidental catch of turtles in fishing gear (especially gill and trawl nets) has been reported as a major cause of turtle mortality along the Indian coast including Tamil Nadu since the 1980s (Bhupathy and Saravanan 2006). Turtles drown when they are trapped in these nets or they are killed when they are removed from the nets. Mortality of turtles along the northern Tamil Nadu coast is found to be highest during January, which is prior to the peak nesting season. However, direct exploitation of turtles for food is largely restricted to southern Tamil Nadu.

Marine turtles were regularly exploited for food along the southern coast of Tamil Nadu. Prior to the implementation of the Indian Wildlife (Protection) Act, 1972, large numbers of green and olive ridley turtles were exported for meat (Agastheesapillai and Thiagarajan 1979). Since the implementation of the Act, the exploitation has gradually declined due to awareness and the presence of field staff of the wildlife wing of the Tamil Nadu forest department in some areas but continues in many pockets.

The Forest Department has been active along this coast from the 1980s when several hatcheries were established. In 1982-83, there were hatcheries at Point Calimere, Vanavan Mahadevi and Arcotthurai, where a total of 255 nests were collected. The following year, hatcheries were established again at Point Calimere and Vanavan Mahadevi, and a third at Vizhundamavadi, and a total of 249 nests were collected this time. About 30,000 eggs were collected and incubated each of the years, and about 25,000 hatchlings released, with a supposed hatching success of 80% at each of the hatcheries. The hatcheries were maintained by the forest department with the help of Abdul Rahaman and his colleagues at the Department of Zoology, AVVM Sri Pushpam College in Poondi.

The hatcheries were closed due to lack of funds in 1987 but revived in 2000 by A. D. Baruah, the Wildlife Warden of Point Calimere Wildlife Sanctuary. With the help of the sanctuary biologist, they constructed a hatchery and collected 14 nests and released about a 1000 hatchlings. Nearly a decade later, another Wildlife Warden, Velusamy reported that the forest department had been setting up olive ridley protection camps at several sites along the coast between 2005 and 2009. The camps, manned by two staff each, helped protect the eggs from depredation and collected nests for hatcheries. Nine such camps were established in 2009.

Students Sea Turtle Conservation Network (SSTCN)

The Students Sea Turtle Conservation Network (SSTCN) was formed by Tito Chandy, Arif Razack, Kartik Shanker with others and established its first hatchery in December 1988. Their sea turtle programme includes beach monitoring, hatchery management, protection of wild nests, education and awareness and has continued from 1988 till present. Initially, the nests were relocated only if there was a threat to them. Some nests were left in the wild and during the hatching period, the nests were monitored and excavated to determine hatchling success. Over the last decade, almost every nest has been relocated from the 7 km stretch (between Besant Nagar and Nilankarai) that has been monitored since 1988.

Since 2010, an additional 7 km (north of Adyar River) has been surveyed. This stretch is one of the most developed public beaches in Chennai and is subject to heavy illumination. Additionally, the presence of several stalls of vendors restricts the nesting area. On an average 100-150 nests have been found each season since 2010. All the nests found in this stretch have also been relocated to a temporary hatchery.

SSTCN primarily functions with the help of volunteers and continues turtle walks, which are open to the public on Fridays and Saturdays, to increase awareness and educate the public about the threats sea turtles face along the coast of Chennai. Several talks and programmes have also been conducted in schools, colleges, and fishing villages targeting young children and teenagers to join.

TREE Foundation

The other major contribution along this coast has come from the TREE Foundation. It started by creating youth groups in the fishing villages along the southern Chennai coast, called ‘Kadal Aamai Paadukavalargal’ (Sea turtle protectors). TREE started its campaign in 2002 with a few villages south of Nilankarai.

By 2003, TREE was covering several villages along the coast and their environmental education work had also expanded. That year, they held programmes in schools, reaching nearly 5000 children. They also conducted a painting competition, a sand modelling competition on the beach for fishing community youth, and a street play using folk theatre by college students about the sea turtles, the environment and fishing communities. In 2004, TREE organised a Peace March on International Peace Day through the villages where they worked.

TREE has now expanded its activities to over 100 km along the Tamil Nadu coast, and 30 km of the Nellore coast in Andhra Pradesh. Working with the Forest Department and the Department of Fisheries, the Kadal Aamai Padhjukavallargal’ (KAP) members patrol the beaches from Periya Neelangarai to Marakanam, south of Chennai, covering 35 fishing villages along 110 km.  Most recently, they have established a turtle rescue and rehabilitation centre and released several rescued turtles.

Night lights at Marina beach, Chennai

Photo: Adhith Swaminathan

SSTCN volunteer meeting

Photo: V. Arun

Eggs being extracted for relocation to a hatchery

Photo: V. Arun

Key figures in turtle conservation and research in Tamil Nadu

• Satish Bhaskar

• Bhupathy Subramanean

• Valliapan

• Kartik Shanker

• Arun Venkatraman

• Akila Balu

• Adhith Swaminathan

• Sanjeev Gopal

• Romulus Whitaker

• Supraja Dharani

Sources and References

Sources: 

Arun, V. (2011) Students’ Sea Turtle Conservation Network: A victory for volunteerism! Indian Ocean Turtle Newsletter 14: 21-25.

Bhupathy, S. and S. Saravanan. 2006. Marine Turtles of Tamil Nadu. Marine Turtles of the Indian Subcontinent (eds. K. Shanker and B.C. Choudhury). Pp. 33-57. Universities Press, Hyderabad. India.

Bhupathy, S., M. Vijay, A.M.A. Nixon, J. Subramanean, R. Karunakaran and J. Gokulakrishnan. 2006. The status of sea turtle populations on the Tamil Nadu and Kerala coasts. Towards an integrated and collaborative sea turtle conservation programme in India: a UNEP/CMS Project Report (eds. K. Shanker and H.V. Andrews). Centre for Herpetology/Madras Crocodile Bank Trust, Tamil Nadu.

Shanker K. 2016. From soup to superstar. HarperLitmus.

Shanker, K. 2003. Thirty years of sea turtle conservation on the Madras coast. Kachhapa 8:16-19.

References:

Agastheesapillai, A., and R. Thiagarajan. 1979. Biology of the green turtle Chelonia mydas (Linnaeus) in the Gulf of Mannar and Palk Bay. J. of the Marine Biol. Assoc. of India 21 (1&2). 45–60.

Banugopan, K, and P Davidar. 1998. Status of sea turtles along the Pondicherry coast, India. Hamdryad 24: 43.

Bhupathy, S. and R. Karunakaran. 2003. Conservation of olive ridley sea turtles lepidochelys olivacea (reptilia/chelonian) along the Nagapattinam coast, southeast coast of India. Indian Journal of Marine Sciences 32 (2). 168-171.

Bhaskar, S. 1981. Sea turtle survey of southern Tamil Nadu. Report to the WWF-India.

Chacko, P.I. 1943. A note on the nesting habitats of the olive logger-head turtle, lepidochelys olivacea (eschscholtz) at Krusadai island. Current Science 12: 02.

Kar, C. S., and S Bhaskar. 1982. Status of sea turtles in the eastern Indian Ocean. Biology and Conservation of Sea Turtles (ed. K Bjorndal). Washington DC: Smithsonian Institution Press. 365–372.

Pandav, B. 2000. Conservation and management of olive ridley sea turtles on the Orissa coast. PhD Thesis, Utkal University, Bhubaneshwar, India.

Sanjeeva Raj, P. J. 1958. Egg-laying habits of sea turtles described in Tamil Sangam literature. J. of the Bombay Nat. Hist. Soc. 55: 361–362.

Subramanean, J. 2005. Nesting and adult mortality of the olive ridley sea turtle along Mamallapuram coast, Tamil Nadu, south India. Herpinstance 2(2) 5-7.

Valliappan, S, and R Whitaker. 1974. Olive ridleys on the Coromandel coast. Chennai: Madras Snake Park Trust. 10.

Whitaker, R. 1977. A note on sea turtles of Madras. Indian Forester 103(11): 733–734.