Studies on the impact of Fisheries on the Biodiversity of Marine Fish Resources of Karnataka Coast

Marine capture fisheries are the most diverse of the major global food–producing sectors, both in terms of the range of species harvested (Froese and Pauly, 2000) and harvesting technologies used (von Brandt, 1984). The current catch from the oceans, some 80 million tonnes annually, has, in the view of FAO, reached the practical maximum that we can expect to take from wild fish stocks. The more valuable the fish are, and the less costly it is to catch them, the lower will be the sustained yield. Thus, valued species will tend to be overfished, unless specific actions are undertaken to prevent this from happening (Clark, 2007). India is one among the nations blessed with abundant as well as diverse germplasm. It has, out of 27,800 fish species reported globally; about 2,649 species (11%) (Lal and Jena, 2011). Fishing activities in the pre–independence days used to be carried out at a subsistence level, almost exclusively by the traditional fishermen. Today, this sector has attained the status of a capital–intensive industry, warranting close monitoring and management for sustained development. The marine fish production in the country progressively increased from 0.6 million tonnes in 1950s to more than 3.0 million tonnes in 2008 (Mohamed et al., 2010). Karnataka state has been a pioneer in the introduction of new mechanized fishing technologies and development of fishing harbours. Consequently, the state has the largest purse seine fleet in India and its trawl fleet is comparatively modern and dynamic. The introduction of new and more efficient gears resulted in steep increase in marine fish production in the state during the 1970s and 1980s (Mohamed et al., 1998). The transition from 1980s to 90s showed a decline in the production rate of the state, although the national average moved up. However, in 2000s, the production has again shown an upward trend. The marine fishery along the Karnataka coast is very dynamic in nature particularly with year–to–year expansion in grounds and decreasing mesh sizes in fishing gears