| Abstract: | Larvae and juveniles of the green abalone grow and survive well at temperatures in the range 20–28°C. A program of hatchery research with this species utilizing thermal effluent has been in progress since 1979 at the Redondo Beach Electric Power Facility, Southern California Edison Company. All life stages may be cultured in the effluent seawater with temperature regulation by admixture of ambient seawater when required. Using thermal effluent, growth rates of juveniles are increased by a factor of 1.5–2.0 over those reared at ambient temperatures (14–20°C) characteristic of southern California. The time to harvest for seed 1–2 cm is reduced from about one year to six months. While optimal temperatures for larvae and postlarvae fall in the range 20–24°C, juveniles are more broadly tolerant of heat and exhibit a growth optimum in the range 24–28°C. The upper lethal limit for juveniles is 31.5°C (LD50, 48 hours). Postlarvae, juveniles and adults have exhibited no indications of unfavorable conditions in power plant effluent. Young adults at 1.5 years (4–5 cm) became reproductively mature and yielded viable larvae. Both hatchery-reared and wild-caught adult green abalone were conditioned to spawning readiness during winter months (natural period, spring-fall) when held in a mixture of effluent and ambient seawater at 20–24°C. Progeny from this research were provided to the California Department of Fish and Game for release in experimental plants. Approximately 30,000 juveniles were produced in 1980–81. |
