seaturtle.org : MTN : ARCHIVES : Sign In
Marine Turtle Newsletter 67:15-16, © 1994
Bivash Pandav1, B. C. Choudhry1, and C. S. KAR2
1Wildlife Institute of India, P. O. Box 18, Dehradun - 248 001, India
2Mangrove Forest Division (Wildlife), Rajnagar, Kendrapara, Orissa, India
Gahirmatha beach located in the Bhitarkanika Wildlife Sanctuary, Orissa, supports the largest known nesting concentration of olive ridley turtles (Lepidochelys olivacea) in the world (Bustard 1976; Kar and Bhaskar 1982; Dash and Kar 1990). There is also another mass nesting site at the Devi River mouth, Cuttack District, 100 km south of Gahirmatha (Kar 1982). During a recent survey of sea turtle nesting beaches along the Orissa coast (December 1993 to May 1994) by the Wildlife Institute of India in Dehradun, a new olive ridley sea turtle rookery was discovered at the mouth of Rushikulya River, 300 km south of the Gahirmatha mass nesting beach. The rookery extends 6 km from Puruna Bandha village (1 km north of the Rushikulya River mouth) to Kantiagada village. The nesting beach is 1 km east of the Madras-Calcutta National Highway No. 5 and the Southeastern Railway line near Ganjam town. It is 8 km north of the Gopalpur port. The nearest large city is Berhampur, 30 km away.
The beach is more or less flat with scattered sand dunes 2-3 m high. Average beach width is 80 m above the high tide line, although in some places the width exceeds 100 m. Vegetation consists of scanty growth of Ipomea pescaprae and Spinifex littoreus. One conspicuous feature is the absence of Casurina trees which are otherwise planted throughout the Orissa coast. The backwater of the Rushikulya River extends 4 km northwards along the nesting beach and a cashew plantation is situated behind the backwater. The Palur Canal which connects Chilka lake with the Bay of Bengal runs parallel to the nesting beach for 8 km.
Our local resource person for this area reported the initiation of mass nesting at this rookery during the night of 1 March 1994, which continued until 1100 hr the next day. Nesting concentration was highest the first three nights and then decreased. Mass nesting continued until 8 March; sporadic nesting was recorded until 24 March. The number of gravid females using the beach was estimated by counting the number of nest pits in random plots 20 m x 20 m, and then extrapolating this number to the full area of the beach where nesting had taken place. Thus, we conclude that 200,000 olive ridleys nested from 1-8 March 1994. Maximum nesting concentration was observed on 1 km in front of Puruna Bandha village and on 4 km from Gokharkuda village to Kantiagada village. Nesting concentration was particularly high on the beach in front of Gokharkuda village where, prior to a flood in 1991, the Rushikulya River met the sea. The 1991 flood altered the river's course and it now opens into the Bay of Bengal, 4 km south.
Hatchlings began emerging on 21 April 1994. The emergence of hatchlings continued for four nights. Hatch success (number of hatchlings successfully emerging from the nest/ number of eggs laid) was 67.4% (n=40).
There are two permanent fishing settlements (Gokharkuda and Kantiagada) on the nesting beach. Local fishermen use catamarans for fishing in the sea, which is of little threat to the turtles. However, a moderate amount of trawler fishing occurs near the nesting beach and a fishing jetty in the mouth of the Rushikulya River is currently under construction. The jetty is expected to increase mechanized fishing activity near the nesting beach. Other threats to the turtles include egg collection by both residents and beach predators. Eggs are eaten locally but not commercially exploited. The number of nests excavated by human beings is much less than the number lost to feral dogs and jackals.
The rookery at present does not come under the jurisdiction of any protected area. According to local villagers, large numbers of turtles nest every year with the onset of the summer season. The mass nesting of olive ridleys at Gahirmatha took place from February 2-11 this year. The mass nesting at the Rushikulya rookery commenced exactly one month later. It is not clear whether the Gahirmatha population is the same as that nesting at Rushikulya, or if the Rushikulya population is distinct. Tagging and monitoring are urgently required to confirm these and other important details.
Bustard, H. R. 1976. World's largest sea turtle rookery? Tigerpaper 3:3.
Dash, M. C. and C. S. Kar. 1990. The Turtle Paradise: Gahirmatha. Interprint, New Delhi. 295 pp.
Kar, C. S. 1982. Discovery of second mass nesting ground of the Pacific olive ridley sea turtles in Orissa, India. Tigerpaper 1:5-7.
Kar, C. S. and S. Bhaskar. 1982. Status of sea turtles in the eastern Indian Ocean, p.365-372. In: K. A. Bjorndal (Editor), Biology and Conservation of Sea Turtles. Smithsonian Inst. Press, Washington D. C.