EFFECTS OF TEMPERATURE AND SALINITY ACCLIMATION OF ADULTS ON LARVAL SURVIVAL, PHYSIOLOGY, AND EARLY DEVELOPMENT OF LYTECHINUS-VARIEGATUS (ECHINODERMATA, ECHINOIDEA)

Larval survival and developmental rates of Lytechinus variegatus (Lama rck) were determined as a function of temperature and salinity in two experiments by: (1) directly transferring fertilized eggs to 35, 30, 2 7.5, 25, 20, 15, and 10 parts per thousand S seawater at 18 and 23-deg rees-C, and (2) acclimation of adult sea urchins to the conditions des cribed above for 1 to 4 wk prior to spawning. Developmental rates and percent survival of larvae prior to metamorphosis varied directly with salinity. Survival of plutei to metamorphosis decreased at salinities below 35 parts per thousand (Q10) values for metamorphosis = 0.380 to 0.384). Temperature and salinity significantly (P < 0.05) affected me tabolic rates of L. variegatus plutei. These results show that L. vari egatus larvae are stenohaline when compared to larvae of other echinod erm species. LC50 values (parts per thousand S), developmental rates, and survival to metamorphosis indicate that acclimation of adult sea u rchins to lower salinity prior to spawning and fertilization does not enhance development or survival of embryos exposed to low salinity.