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Blue revolution goes awry

AQUACULTURE, once eulogised as a trouble-free money-spinner, is now causing sleepless nights for its promoters. Last year, a mysterious viral disease, nick- named "white spot", had swept Tamil Nadu, Andhra Pradesh and Kerala, decimating a large part of the cultured shrimp crop. After ravaging the industry in West Bengal, the scourge has recently affected the prawn farms of Karnataka's Uttar Kannada district. The genesis of the outbreak has been traced to infected prawn seeds released by an aquaculture company in the Aghanashini river. The disease has left farms in the district's Kumta taluk, through which the river flows, full of dead prawns. The aquaculture industry in other Asian nations is similarly afflicted. Taiwan, the world's largest shrimp exporter till a few years ago, has seen its output fall from 90,000 metric tonnes (mt) in 1987 to 25,000 mt in 1989 owing to a disease-hit industry. Experts say intensive production, too rapid an expansion, overexploitation of groundwater and self- contamination of the water in the farms have led to the outbreaks.