Postlarval abundance as a possible index of fishing successin the prawn Metapenaeus dobsoni (Miers)

The penaeid prawn Metapenaeus dobsoni (locally known as poovaalan in the bigger sizes and thelly in the smaller sizes) spawns in the inshore waters of the Southwest coast of India (Menon 1951) almost throughout the year with the peak breeding season between June, July and November (Menon 1955 and George 1962). The eggs hatch and through different stages quickly transform to postlarvae which are noticed to enter in very large numbers into the various estuaries and backwaters along the coast and to use these waters extensively as nursery grounds during their juvenile growth period. The very lucrative paddy field prawn fishery and the backwater fishery for prawns of Cochin and other areas of the coast is singularly dependent on this habit of the prawn. After a growth of about 9 or 10 months these prawns return to the coastal waters where they are henceforth exploited by both the indigenous fishing as well as the mechanised fishing operations.