17-Availability of Crabs in Chilika Lagoon in relation to some hydrological parameters

Abstract

Chilika Lagoon, a much focused designated Ramsar site of international importance and largest coastal wetland ecosystem in Indian subcontinent, is one of the finest repositories of aquatic biodiversity and steady sources of fishery. In the process of degradation of ecosystem, the Lagoon fishery became the major victim .Chilika is a hot spot of biodiversity with 277 species of fishes and 34 species of crabs. The different species of crabs found in Chilika are Scylla species, Protunus species, Charybdis species etc. The crab availability depends upon the hydrological parameters of the Lagoon. The major hydrological parameters affecting the crab availability are salinity, temperature and dissolved oxygen. Salinity plays the major role in the availability of crabs. The study was carried out in the four sectors of the Lagoon during June 2007 to May 2008. The highest salinity was found to be 27.3 ppt in the outer channel sector. The lowest was recorded in the northern sector which was found to be 7.1 ppt. The highest temperature was recorded to be 38.5°C and lowest was 25.2°C. Similarly the dissolved oxygen value ranged from 5.9 mg/I to 8.3 mg/I. Crabs are abundantly available in the outer channel sector as the salinity value in this sector is suitable for them. In the northern and central sector their availability of crab was low in comparison to the outer channel sector.