Characterisation of the nesting beaches of olive ridley sea turtle in Orissa coast and development of habitat suitability models in the Bay of Bengal
Student name: Ms Neena Priyanka
Guide: Dr P K Joshi
Year of completion: 2008
Host Organisation: Wildlife Institute of India, Dehradun
Supervisor (Host Organisation): Prof B C Choudhury and Dr K Sivakumar
Abstract: The mass nesting of Olive ridley sea turtles in the Orissa coast generally occur during the month of
November to March every year. It was expected that perhaps the beach condition of the turtle rookeries
such as Gahirmatha, Devi and Rushikulya rivers mouth are more conducive for mass nesting. However, the
population size of sea turtles during the mass nesting varies from time to time due to frequent changes in
the coastal landscape, geomorphology and adjoining seascape. The present study was carried out for
characterisation of the Olive ridley sea turtle nesting beaches from the sea water line in Ganjam
(Rushikulya river mouth) and Baleshwar (Gahirmatha) region in Orissa to understand the determining
landscape factors of mass nesting. Landsat satellites images of periods 1990, 2000 have been used for this
study. Supervised classification had been used for preparation of land use /land cover map using two date
data (2000 and 2008). The spatial distribution of major land use /land cover classes which have been
identified are settlement with vegetation, plantation, sandy area, dense mangrove forest, open mangrove
forest, agricultural lands etc. Different layers of information such as, canal, forest boundary, road and rail
networks have been superimposed on the classified map. The other collateral data like rainfall,
temperature, composition of beach, movement of mechanized boats /trawlers are taken in GIS environment.
The integration of spatial and non-spatial database in GIS environment have identified the common beach
characteristics in the existing nesting beaches, which have been used as common parameters for
identification of sporadic nesting sites in the coast. Oceanographic parameters such as sea depth, sea
surface temperature, phytoplankton abundance and water current have also been used and developed a
Habitat Suitability Model (HSM) of the Olive ridley sea turtle in the Bay of Bengal during their migration
to foraging areas. This model helped in predicting the suitable foraging habitat of the Olive ridley sea
turtle in the Bay of Bengal and also to identify the use of sea turtles in the proposed oil and natural gas
blocks. The present study, therefore, gives insight for understanding of the distribution and movement of
olive ridley in the coastal waters off Orissa coast, potential foraging ground and overlapped area for better
conservation and also for rational planning of developmental activities such as the possible oil and natural
gas extraction in these regions.
