REPRODUCTION AND SURVIVAL OF THE PILEWORMNEREIS SUCCINEAIN HIGHER SALTON SEA SALINITIES

Abstract

The Salton Sea is a large (200 square miles) closed salt lake in a below-sealevel depression in the Colorado Desert of southeastern California. The Sea was formed accidentally from 1905 to 1907 when flood waters of the Colorado River broke through poorly constructed headgates of an irrigation canal. Following repair of is little published information on high salinity adaptations in polychaetes (Bayly, 1972;Oglesby, 1978), and only one published study on the effects of higher salinities on N. snccinca in the Salton Sea. Hanson (1972) observed that pileworms survived 96-hr exposures to salinities as high as 67.5'vV, but speculated

Does the introduced polychaete Alitta succinea establish in the Caspian Sea?

“…Kuhl and Oglesby (1979) have shown that temperatures as high as 34°C do not have any marked effect on adult survival and reproduction of A. succinea. However, higher temperature may have a synchronizing effect on epitokal metamorphosis in A. succinea (Fong 1991).…”

“…They found normal development of embryos at 10, 15, and 20 %, except for the combination of 10 % and 10°C. Kuhl and Oglesby (1979) suggested survival limits of A. succinea at 1 and 80 %, while successful fertilization and development can only occur between 10 and 45 %. Kristensen (1988) found that the distribution of this worm in a Danish estuary was restricted by salinities lower than 10 %.…”

Detailed study of water quality, bottom sediment, and biota associated with irrigation drainage in the Salton Sea area, California, 1988-90

“…Pileworms are restricted to substrates of fine sand and silt and spend most of their lives in burrows in mud or among masses of barnacles (Kuhl and Oglesby, 1979). Pileworms are most abundant in sediment at water depths of 15 to 25 ft, but they can be found seasonally at all depths in the Salton Sea.…”

“…Mature pileworms leave their burrows at night and swim to the surface to spawn. Spawning occurs throughout the year and peaks during spring and autumn (Kuhl and Oglesby, 1979). The eggs and larvae of pileworms are planktonic, and all stages of the pileworm are extremely important to Salton Sea food chains.…”

Metridium senile: dispersion and small scale colonization by the combined strategy of locomotion and asexual reproduction (laceration)

“…It might be that the salinity difference blocks the immigration of adult members of other M. senile populations (less pre-adapted than the local 'brown') and larvae from the North Sea into the Baltic Sea. For many species it is known that the larvae are much less tolerant to salinity-stress than the adult form (Innes & Haley 1977, Young & Hazlett 1978, Kuhl & Oglesby 1979, Berry & Hunt 1980.…”