Ecologically Important Areas of
Tamil Nadu Coast
The lake extends to about 59km in north to south direction with a maximum width of 17km in east to west direction in the northern sector of thr lake. The lake at its southern end, near north of Pulicat town open into the Bay of Bengal by narrow pass into the sea. The lagoon has a high water spread area of 460 kmē and low floodwater spresd area of 250kmē.
The lake at its southern end, near north of Pulicat town opens into Bay of Bengal by a narrow pass into the sea. According to Paul Raj 1976, from March till September, the mouth gets silted and reduced in width and depth, as it shifts position, simultaneously from south to north. The mouth normally gets completely closed once in above five years or even little more frequently if there is no monsoon flood in any particular year.
Fig: Ecologically Important Areas in Tamil Nadu : Pulicat Lake
Map of South Pulicat lake Click here
Pulicat a Bird Sanctuary:
Pulicat is the third most important wetland for the migratory shore birds on the eastern seaboard of India. The lake is an extremely important area for a variety of resident and migratory birds like waterfowl, pelicans, herons, egrets, storks, flamingos, ducks, gulls and terns. The lagoon supports significant populations of Tachybaptus ruficollis, Pelicanus philippiensis, Mycteria leucocephalus, Anastomus osticans, Threskiornis melanocephalus, Platalea leucorodia, Dendrocygna javonica and Anas poeciolrhyncha. More number of greater flamingos (P.rubera) occurs in the Andhra Pradesh part of the sanctuary, around the islands of Venadu and Irukkam.
Biodiversity of Pulicat:
Pulicat Lake supports rich fauna and flora. The seagrass Halophila sp. and Siringodium sp are commonly distributed in this lake supporting many faunal community. The Institute for Ocean Management, Anna University made the quantitative analysis of the present status of biodiversity of Pulicat Lake shows that Phytoplankton (49), Macro algae (12) Seagrass (Halophila sp, and Halodule sp), Zooplankton (88), Benthos (81), Fish (39) (the dominant species including Chanos chanos, Mugil cephalus, Liza parsia, Plotosus canius, Sardinella sp. Hilsa keele etc.).
Siltation and periodic closure of the bar mouth:
The Pulicat Lake is confluent with the Bay of Bengal across a bar of about 3km form the Pulicat lighthouse on the Tamil Nadu part. The dynamic process of sediment transport along the spit reduces the mouth of the lake. At the same time, the deposition of fluvial sediments in the lake basin is increasing and the two rivers also deliver sediment into the basin rendering the lake shallow and turbid. Due to limited freshwater supply and tidal action, the mouth of the lake gets silted up and closed during the summer seasons. The closure of lake mouth takes place around pre-monsoon (June-July) and lasts till monsoon (Oct-Nov). During the rainy season, the flood level rises by several feet and in the dry season (April and June), if the bar remains closed, the lake acts as a large evaporating basin. Therefore, the water level in the lake can either be above or below the sea level and the salinity can either low or high depending on the flood discharge into the lake during the northeast monsoon. These factors have great bearing on the flora and fauna of the Pulicat Lake and fisheries. The shifting of the lake mouth siltation and consequent reduction in the tidal impact, have naturally led to the decline in recruitment of commercially important species of prawns and mullets.
Pollution and Human Impacts:
Pollution from pesticides, sewage, agricultural chemicals and industrial effluents are gradually becoming the major threats. It is speculated that the Arani and Kalangi rivers draining into the lake bring in fertilizers and pesticides with runoff from the agricultural fields in the drainage basin. The domestic sewage forms a more diffuse input. The Pulicat Lake is thus being increasingly subjected to many kinds of anthropogenic disturbances.
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