chilka lake

Chilika has a pride of place in Orissa's literature and culture, and has influenced the poets and philosophers. It has held great significance for planners, scientists, international organizations like 'The Wetlands International' and 'Asian Wetland Bureau'. Chilika lagoon has been designated as a Ramsar site (Wetland of International importance) from the 1st October, l981.

TOPOGRAPHY
The water spread of the lagoon varies between 1165 Sq.km in monsoon to 906 Sq.km during summer, and extends over Puri, Khurda and Ganjam districts. The lagoon itself can be broadly divided in to four natural sectors based on salinity and depth: the southern zone, central zone, northern zone, and the outer channel.
ISLANDS
Numerous islands are present in the lagoon, prominent among which are Kalijai, Honeymoon, Barakuda, Breakfast, Birds Island, etc.
WILDLIFE SANCTUARY
One of the submerged (potential) islands covering, an area of 15.53 Sq.km has been notified as Chilika (Nalaban) Wildlife Sanctuary on 17th December l987. The whole area of the Chilika Lake, excluding the area notified as Sanctuary has been declared as a 'Closed Area' for a period of five years with effect from 16th December 2002.

DRAINAGE
The ecosystem features of Chilika comprising of tidal ingress from the sea, which mixes with the fresh water brought by rivers like Daya, Bhargabi, Luna, and large number of rivulets.
HUMAN HABITATION
Several ION islands are situated in this lagoon, inhabited by large human population (1.3 lakh approx.) variously dependent on this wetland for sustenance. A number of villages and towns around the lagoon are closely associated with the wetland, in one way or the other for economic activities. About 70% of this population depends on fishing as the means of livelihood.
BIODIVERSITY
The Chilika Lagoon is hot spot of rich Biodiversity.

FLORA
There are 546 species of angiospermic plants belonging to 379 genera and 107 families, above 100 phytoplankton genera, 20 species of weed and 7 pteridophytic species documented so far in the Lagoon and the islands. FAUNAChilika is very rich in both invertebrate and vertebrate fauna. This Ramsar site is the habitat for the largest congregation of waterfowls in India.
AVIFAUNA
Over a million birds congregate in this water body for feeding and roosting. Migration commences in late September and the birds remain up to April, but the peak congregation period is mid-December to middle of January. Birds belonging to over 230 species including 14 birds of prey (32% aquatic, 22%waders, and 46% terrestrial birds) are seen in this lake, of which 95 species are intercontinental and local migrants. Flocks of migratory waterfowl arrive from as far as the Caspian Sea, Lake Baikal, remote parts of Russia, central and south East Asia, Ladakh and the Himalayas for feeding and roosting. 15 species of ducks and two species of geese (Order: Anseriformes), cover over 70% of the migratory birds which visit this lagoon annually. The ducks and geese are followed by coots, rails and cranes (Gruiformes) 15%; waders/shore birds (Charadriformes) 12%; pelicans (Pelecaniformes) 1.5%; grebes (Podicipediformes) 1%; kites, eagles etc. (Falconiformes) and kingfishers (Coraciformes) 0.5%.
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WATERFOWL ESTIMATION-2004
Chilika holds the highest concentration of waterfowl. The 2004 survey estimates total of 8, 66,477 birds representing 137 species of which 85 are migrant species. Waterfowl visitation to Chilika in 2004 was 1.9 times the number in comparison to the year 2003.

In Chilika during the current bird migration season, maximum congregation of waterfowl (migratory and local) was observed in peripheral marshy areas of the Chilika lagoon such as: Kalupada ghatt, Manglajodi, Sorana, etc.

OTHER FAUNA
The other vertebrate fauna includes:· 321 species of fish and crab (fresh water, estuarine and marine species), · 7 species of amphibians, · 30 species of reptiles (12 species of lizards and 18 species of snakes) and · 18 species of mammals. Two major crabs species (Scylla serreta and Neptunus pelagicus), available in Chilika are of commercial importance.

ENDANGERED SPECIES
Most notable and endangered species also included in the Schedule-1 of the Wildlife Protection)Act ) available in the lagoon are:· Barkudia insularis, a limbless lizard/skink (this skink is named after the "Barukuda" island of the lake); · an aquatic mammal i.e., Irrawaddy dolphin, Orcaella brevirostris ,· Fishing cat( Felis viverrina), · White bellied sea eagle (Haliaeetus leucogaster), White spoon bill (Platalea leucorodia), Osprey (Pandion haliaetus), and · Spoon billed sandpiper (Eurynorhynchus pygmeus).
DOLPHINS
The population of Irrawaddy or Snubfin dolphins, Orcaella brevirostris (locally known as "Bhuasuni Magar") is threatened due to intensive fishing and plying of mechanised boats in the lake. At present there are about 80-90 Irrawaddy dolphins in the entire lake. A small population of Bottle nosed dolphin, Sousa chinensis also migrate in to the lagoon from the sea.

ARRIBADA OF OLIVE RIDLEY SEA TURTLES
The mass nesting beach (rookery) along the Chilika coast is at Rushikulya which is located at the southern Orissa coast. It spreads over six km. stretching from the coastline in front of village Purunabandh (one Km north of Rushikulya river mouth) to the beach in front of Kantiagada village of Ganjam District. The nesting beach is much wide, more or less flat with scattered sand dunes of 1 - 2 m high. The average beach width is about 100 m from near the high tide line, though at some places the width of the beach is more than 100 m. About 2,00,000 turtles estimated to have nested in this rookery in the arribada of March, 1994. In subsequent years there was a decline in the number of turtles nesting at this rookery (1994-95: 0.60lakhs; 1995-96: 1.18 lakhs; 1996-97: 0.25 lakhs; 1997-98: 0.085 lakhs). There was no mass nesting in this rookery during 1998-99, 1999-2000 and 2002. However, a total of 1.59 lakh turtles came to the Rushikulya rookery during the first mass nesting period of 2000-01. The first mass nesting at this rookery continued over a 7 days period starting from 26th February to 4th March 2001. The mass nesting figures for the last three years are as follows (2001-02:0.35 lakhs; 2002-03:2.8 lakhs; 2003-04: 2.01 lakhs).

THREATS
Chilika Lake is threatened by siltation, eutrophication, change in salinity regime, proliferation of freshwater weed, increased aquaculture activities, changes in species composition, depletion of bio- resources, and decrease in fish population etc.
People have been using migratory birds arriving in Chilika for wintering as a source of protein supplement for quite some time. With the passage of time, this source of protein supplement has also become a source of livelihood for them. The inaccessibility of certain pockets due to weed infestation has boosted their activity as they find easy escape routes in these areas.

HYDROLOGICAL INTERVENTION
In a major intervention to manipulate the lake hydrology, a new mouth was opened near Ramabhartia in the year 2000 by the Chilika Development Authority (CDA), Bhubaneswar to let fresh ingress of seawater into the lake. The results of this intervention indicate that the salinity levels inside the lagoon have increased to certain extent in comparison to previous years, which apparently has led to decrease in the weed growth area and increase in fish catch. Impact of this manipulation (increased salinity level in the lake) on the ecosystem of the lake as a whole and Nalaban Sanctuary in particular and on the population of migratory birds / waterfowl in the lake needs closer assessment.
PROTECTION MEASURES
In an innovative experiment to wean the poachers away from poaching, a massive awareness programme has been undertaken and bird protection committees have been formed. These committees assist the Forest Department in their protection efforts during the migratory season. In some areas, like Mangalajodi and Bhusandpur, the response from the villagers has been encouraging. These efforts are supplemented with the establishment of anti-poaching camps at strategic points along the coast line. To encourage eco-tourism, training camps for eco-guides and boat-man associations at Balugaon and Satpada are being organised.
HABITAT DEVELOPMENT
Habitat development inside the sanctuary is being done with funds received from Govt. of India and Chilika Development Authority. These measures include raising up of plantations, digging and renovation of creeks and digging of pon

CONSERVATION AND MANAGEMENT STRATEGY

The State Environment Department and the Chilika Development Authority have taken several measures for conservation and management of this unique wetland and its rich biodiversity, with the support of the Ministry of E &F, Govt. of India. These measures include:· Protection of migratory waterfowl and other species prone to poaching for meat.· Catchments area treatment· Weed control· Restoration of the feeding and roosting habitat of water fowl· Pollution control· Creation of awareness about the values and functions of wetland· Research and development activities· Community participation· Capacity building· Building of Data base of the lagoon · Promotion of eco-tourism
The changing profile of the lake has led to new challenges. The bird congregation, which was largely confined to Nalaban and other four to five areas, has now dispersed to peripheral areas such as Kalupada, Mangalajodi, and Bhusandpur, etc. This has posed a problem of protection of birds due to difficulty in accessibility of the area and constraint of resources. Increase in tourism inside Chilika has given rise to death of Irrawaddy dolphins, which may at a later stage be detrimental to the overall population of these endangered dolphins. This, however, has also offered opportunities to work hand in hand with other stakeholders working in the area for overall conservation of the lagoon.