Inland Fisheries

Vembanad Backwaters

Vembanad Lake is the India's longest lake, and is the largest lake in the state of Kerala. It is also one of the largest lakes in India. The total area of the water body is 256 km². The Vembanad wetland system covers an area of over 1512 km². The lake is bordered by Alappulha, Kottayam, and Ernakulam districts, extending from Cranganore in the north to Alleppy in the south. It lies at sea level, and is separated from the Arabian Sea by a narrow barrier island. Canals link the lake to other coastal lakes to the north and south. Several rivers flow into the lake, including the Achenkovil, Manimala, Meenachil, Muvattupuzha, Pamba and Periyar. The lake surrounds the islands of Pathiramanal, Perumbalam and Pallippuram. The Vembanad Lake is approximately 14 km wide at its widest point. A unique characteristic of the lake is the location of the Thannermukkom salt water barrier constructed to prevent tidal action and intrusion of salt water into the Kuttanad low-lands. It is the largest mud regulator in India. This barrier essentially divides the lake into two parts - one with brackish water perenially and the other half with freshwater fed by the rivers draining in to the lake. This barrier has helped the farmers in Kuttanad - where farming is done below sea level. It has however also created ecological problems, primarily, the rampant propagation of the Water Hyacinth in freshwater.

Fish and Fisheries

The exploited fishes, prawns, etc., include 110 species of fishes, six species of penaeid prawns, three species of palaemonids, three species of crabs and large quantities of black clam Villorita cyprinoids. The major fisheries of the Kerala backwaters are mullts like Mugil cephalus, M. macrolepis, M. cunnesius, M. parsia, M. scheli; pearl spots like Etroplus suratensis and E. maculatus; catfishes and Hilsa ilisha. Two species, namely Dayella malabaricus and Ehirava fluviatilis (Family: Clupeidae, Subfamily: Pellonulinae) form minor fishery. Among the prawns, Metapenaeus dobsoni, M. monoceros, M. affinis, Penaeus indicus and the freshwater prawn Macrobrachium idella form good fishery. Of the several species of crabs, the mudcrab, Scylla serrata constitute the fishery. Molluscan fishery of the backwaters including the Vembanad Lake is largely sustained by the black clam. Clam beds are found extensively in the backwaters and the fishing methods employed are handpicking and storing them in collection baskets, combing and heaping at low tides with toothed-iron rakes and rakes fitted with bagnets.

Conservation and management

In the recent years, there has been a marked decline in prawn catches, both from impoundments and open waters. Human intervention, mainly pollution and over fishing are the important factors to be reckoned with.