Fresh water prawns of the genus Macrobrachium have a world-wide tropical, sub-tropical distribution. M. rosenbergii (de Man), native to the tropical western Pacific and southeast Asia, is the largest, fastest growing prawn of the genus and most important to aquaculturists. Research on the prawn began in 1959 by scientists with the Food and Agriculture Organization in Malaysia. Since then Hawaii has become a center for research and prawns can now be grown in Hawaii to commercial size in a seven-month period