In coastal Orissa, the area of confluence of any river and the sea, which is the deltaic region, is a fascinating ecosystem. Also called intertidal area, this is criss-crossed by estuary, rivers, creeks and creeklets. The land in these estuaries is continually inundated by the saline sea water under influence of sea tide and also sweet water of river. Such lands are covered with mangroves, a kind of vegetation endemic to these areas. The mangroves and the estuaries are the breeding and spawning grounds of varieties of marine life forms such as fishes, prawns, crabs and mollusks. These life forms spend their juvenile stage in the mangrove estuarine ecosystem, and migrate to the sea in the later part of their lives. October to May is the period during which these juveniles are available in abundance in the estuaries and the coastal sea. This is the time for the sea turtles to congregate in these areas, having migrated over large distances in the sea to feed on these fishes etc. in the shallow sea near the intertidal regions. During the months of October to May therefore, shallow sea near the river mouth becomes the feeding ground of the sea turtles, both for the adults and their juveniles. The sea turtles congregate and mate there and then look for suitable undisturbed beaches in these river mouth areas for laying eggs and nesting.
Based on these ecological conditions, certain pockets in the Orissa coast have become the famous mass nesting sites of the Olive Ridley sea turtles. Significant populations of these turtles visit the congregation areas en-masse before the winter months for breeding and nesting. This is a yearly phenomenon. This population represents about 50% of the total world population of Olive Ridleys, and about 90% of the Indian population of sea turtles. Worldwide attention is naturally focused on these rookeries for conservation of this species.
In coastal Orissa, the area of confluence of any river and the sea, which is the deltaic region, is a fascinating ecosystem. Also called intertidal area, this is criss-crossed by estuary, rivers, creeks and creeklets. The land in these estuaries is continually inundated by the saline sea water under influence of sea tide and also sweet water of river. Such lands are covered with mangroves, a kind of vegetation endemic to these areas. The mangroves and the estuaries are the breeding and spawning grounds of varieties of marine life forms such as fishes, prawns, crabs and mollusks. These life forms spend their juvenile stage in the mangrove estuarine ecosystem, and migrate to the sea in the later part of their lives. October to May is the period during which these juveniles are available in abundance in the estuaries and the coastal sea. This is the time for the sea turtles to congregate in these areas, having migrated over large distances in the sea to feed on these fishes etc. in the shallow sea near the intertidal regions. During the months of October to May therefore, shallow sea near the river mouth becomes the feeding ground of the sea turtles, both for the adults and their juveniles. The sea turtles congregate and mate there and then look for suitable undisturbed beaches in these river mouth areas for laying eggs and nesting.
Based on these ecological conditions, certain pockets in the Orissa coast have become the famous mass nesting sites of the Olive Ridley sea turtles. Significant populations of these turtles visit the congregation areas en-masse before the winter months for breeding and nesting. This is a yearly phenomenon. This population represents about 50% of the total world population of Olive Ridleys, and about 90% of the Indian population of sea turtles. Worldwide attention is naturally focused on these rookeries for conservation of this species.
The Crocodile Project started with the objective of building the population to a stage when incidence of sighting could be 5 to 6 crocodiles per KM length of water. The Project sought to make up the natural losses by death and predation through rear and release operation. This involved collection of eggs from the nests as soon as these were laid, incubation and hatching of these eggs in hatcheries under regulated conditions of temperature and humidity, rearing the young juveniles, marking and release of the young crocodiles into Nature in protected areas, and assessment of the degree of success in restocking any protected area with crocodiles released from the hatcheries. To accomplish these tasks, 3 separate research units were established at Tikarpara, Dangmal and Ramatirtha for the Gharial, Salt Water Crocodile and the Mugger, respectively. At the Nandankanan Biological Park, captive breeding plans for all three species were pursued.
THREATS
The sea fishing activities have direct adverse impact on the adult sea turtles and their hatchlings. Olive ridleys usually mate between October to February, when they congregate in the shallow coastal waters for prolonged periods, making them vulnerable to the fishing nets and propellers of the trawlers.
The other threats to sea turtles include: (i) Loss or modification of the nesting beaches due to Casuarina plantation; (ii) Fishing by gill nets; and development of fishing bases at the potential nesting sites and breeding areas; (iii) Strong illumination around nesting beaches which greatly disorients the adult turtles as well as the hatchlings; (iv) Large scale vessel movement in congregation zones severely disturb mating and breeding; (v) Nests and eggs are destroyed by predators like dogs, jackals, hyenas, etc., and by beach erosion.
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