ABSTRACT
Aquaculture constitutes a vital and rapidly growing segment of world ag riculture. The U.S. Department of Agriculture (1998) reported that 20 per cent of fish and seafood consumed in the United States is farm raised. The U.S. aquaculture industry is a recognized segment of the livestock produc tion, larger than lamb, veal, and mutton combined (USDA 1998). Advances in U.S. aquaculture technologies and the strong public demand for safe and wholesome fish products are expected to accelerate industry growth in the next millennium. Catfish, tilapia, salmon, hybrid striped bass, and rainbow trout production make up significant segments of U.S. aquaculture. Catfish continues to lead the U.S. aquaculture production at 535 to 545 million pounds (USDA 1998). In 1989, 1.6 billion fingerlings were cultured and susceptible to infectious agents that we estimate may claim 30 to 50 percent of these fish before they reach food size. Successful vaccination of these young fish against both enteric septicemia (ESC; Edwardsiella ictaluri) and Flavobacterium columnare, two primary infections of catfish, would un doubtedly enhance their total survival to food-size fish.
