REPRODUCTION AND SURVIVAL OF THE PILEWORM NEREIS SUCCINEA IN HIGHER SALTON SEA SALINITIES

¹ Department of Biology, Pomona College, Claremont, California 91711

The polychaete annelid Nereis (Neanthes) succinea is the major benthic detritivore in the Salton Sea, an inland salt lake in southeastern California, and is critical in the trophic chain leading to the sportfishery. In view of the increasing salinity of the Salton Sea, laboratory experiments were conducted to determine critical upper salinity limits for reproduction and survival of pileworms. Atokous (immature) pileworms can survive for extended periods in Salton Sea salinities at least as high as 65, with some reduction of survival in 70, and with only short term survival in 80, more than twice the present salinity of the Salton Sea (36). Heteronereid production is depressed by salinities higher than 50. Reproduction of N. succinea is successful at salinities at least as high as 45, and probably as high as 50. Fertilization and early cleavage stages are less tolerant of elevated salinities than are later development stages such as trochophores.