ABSTRACT
To approach optimal production, aquaculturists typically attempt to modify the culture environment to meet the environmental requirements of the species being cultured. Environmental modification may be as simple as aeration of culture ponds or as complicated as temperature, photoperiod, and dissolved ion manipulation in recirculation systems (Tomasso 1993; Tomasso 1997). An alternate approach is to modify the organism to better match the available environment. This can be done genetically or nutritionally. A ge netic approach could involve either the use of classic selection and hybrid ization techniques or simply selecting existing stocks with a trait of value to an aquaculturist (Tomasso and Carmichael 1991). A nutritional approach would involve the use of dietary additives or supplements that would en hance the ability of the animal to deal with some aspect of a nonoptimal en vironment.
