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28 JOURNAL OF APPLIED AQUACULTURE attain larger ultimate size than diploid siblings. This may be due to the fact that triploids are typically sterile (Purdom 1976; Cassani and Caton 1986) and the energy normally used for reproduction is invested in somatic growth (Thorgaard and Allen 1987). The elimi- nation of reproduction may be useful for the introduction of non- indigenousfishes orwhere the potential far stresses from overpopu- lation exists. Additionally, the stocking of triploid (sterile} fish is a safer method for introducing novel strains that have been selected or bred for specific traits, because triploids will minimize impacts on natural gene pools. Triploids can be produced by causing a fertilized egg to retain its second polar body nucleus (Thorgaard 1983). Current methods used to induce triploidy include chemicals, hydrostatic pressure, and ther- malshocks subsequent to sperm penetration of the egg (Streisinger et al. 1981; Thorgaard 1983; Benfey and Sutterlin 1984; Curtis et at. 1987; Thorgaard and Allen 1987). Near-lethal temperature or pres- sure appears to yield the highest incidence of triploid individuals (Thorgaard 1983); hydrostatic pressure treatment appears to be the more efficient technique (Cassani and Caton 1986). The largemouth bass, Micropterus salmoides, is an important sport fish throughout most of North America, receiving both state and federal fishery management attention. The benefits usually as- sociated with triploidy offer a potential for the species to expand its size capability. This potential, coupled with restrictive size limits, may allow fisheries managers to produce trophy-sized largemouth bass in some locations. It would be most useful in small impound- ments orsimilar situations where reproductive limitations are needed or supplemental stocking is feasible. Triploidy induction of large- mouth bass to our knowledge has never been reported. The objec- tive of this paper is to describe a procedure using hydrostatic pres- sure shocks to induce triploidy in largemouth bass. METHODS AND MATERIALS Largemouth bass used in the experiments were obtained from the wild and maintained at the Texas Parks and Wildlife Department's Heart of the Hills Research Station (HOH). Gametes were obtained by stimulating reproductive condition in adult fish through photo- period and temperature manipulation, then further inducing ovula-