Technical Abstract: Remarkable biotechnological advancements have been made in the aquaculture industry in the past five years. Advancements, in areas such as fish vaccines, improved genetic stock, biosecurity tools and alternative protein sources in fish diets, are necessary to meet the rapid growth of the aquaculture industry worldwide and the ever-increasing demand for fish and other seafood. The incidence and emergence of new infectious diseases has almost paralleled the growth of the aquaculture industry. Efficacious killed S. iniae (US Patent 6,379,677) vaccines and S. agalactiae (patent pending) vaccines were developed and patented by the Agricultural Research Service (ARS), Aquatic Animal Health Research Laboratory (AAHRL) at Auburn, AL and Chestertown, MD using formalin-killed cells and concentrated extracellular products. The finding that extracellular products of these Gram-positive streptococci are important immunogens that confer protective immunity following immunization is a notable advancement in the development of efficacious killed vaccines. Additional biotechnological breakthroughs were the development of attenuated bacterial vaccines. Examples of the first U.S.-licensed attenuated bacterial vaccines are those against enteric septicemia of catfish (ESC) and columnaris disease of catfish. These attenuated vaccines were developed and patented by the ARS, USDA AAHRL at Auburn, AL. (U.S. Patents 6,019,981; 6,881,412 B1) and commercialized by Intervet, Inc., Millsboro, DE. Finally, different methods of vaccine administration for mass vaccination can be employed to maximize the protection conferred by different vaccine types. In ovo immunization of channel catfish eggs (U.S. Patent 5,153,202) with attenuated ESC vaccine resulted in protection against ESC in fingerlings and oral immunization which combines PerOs Technologies, Inc., St. Nicolas, Canada patented OraljectTM technology with ARS patented Streptococcus iniae vaccine (US Patent 6,379,677) was efficacious in tilapia. Deoxyribonucleic acid (DNA) vaccination is another example of a biotechnological advancement to protect fish from pathogens. Improved genetic stocks have played a key role in the growth of aquaculture, especially in channel catfish. Among biotechnological advancements important to biosecurity are the development and use of rapid and early infectious agent detection tests and use of vaccines (discussed above). More recently, new molecular assays such as monoclonal antibody assays and polymerase chain reaction (PCR) tests or variations of DNA amplification techniques are being frequently used to detect fish pathogens.