- Laboratory experiments were conducted to determine how growth and survival of earlylife-history stages of California halibut Pamlichthys californicus are influenced by temperature, and how optimal temperature ranges may change with ontogeny. As halibut developed from eggs to juveniles, highest survival occurred at increasingly higher temperature ranges. Within tolerance limits, growth and development rates of all early-lifehistory stages were directly proportional to temperature. Eggs hatched successfully at 12, 16, and 20°C; at g and 24°C they died prior to embryo formation. Larval survival 17 days after hatching was 23-46% at 16, 20, and 24°C, but almost all larvae died at 12°C after an initial period of high survival. At gOC,larvai development ceased at the early yolksac stage. Survival of 3-month-old juvenile halibut was significantly greater at 20, 24. and 28°C (57-76°70) than at 16°C (31%). Temperature also affected settlement rate; when the temperature of I-month-old larvae was raised from 16°C to 20°C, settlement occurred about a week sooner than settlement of larvae remaining at 16°C. Tolerance ranges of halibut earlylife-history stages determined in the laboratory approximate temperatures encountered by halibut in the field; high densities of newly-settled halibut larvae and juveniles have been collected in shallow areas of bays where temperatures are often higher than the open ocean inhabited by young larvae. These warmer inshore nursery grounds could enhance growth and survival of halibut juveniles.
