Developmental defects in fish embryos from Salton Sea, California

The Salton Sea is the largest inland body of water in California. It currently supports a sportfishery for orangemouth corvina (Cynoscion xanthulus). Other species of importance are the bairdiella (Bairdiella icistius) and sargo (Anisotremus davidsonii). The future status of the fishery is uncertain for several reasons including possible impacts from chemical contaminants entering the Sea via agricultural drains and rivers. There are also relatively large inputs of sewage from the New River and the Alamo River. Although these rivers discharge into the south end, strong currents and winds create rapid dispersion throughout the Salton Sea. Responding to environmental concerns, the State of California Department of Fish and Game supported a study on the population dynamics of Salton Sea fishes. Ichthyoplankton samples were collected for three spawning seasons, and fish embryos were evaluated for normal development. The development of fish embryos has been used for monitoring the effects of pollution in the New York Bight and in northern Europe, where malformation rates of up to 50% were found in embryos collected near highly contaminated rivers and waste dumping areas. This report describes significant incidences of malformed fish embryos collected from the Salton Sea. However, because of extreme hydrographical conditions present atmore » the Sea which might be at least partially responsible for the observed malformations, supporting information on embryonic development was obtained in this study by controlled spawning of Salton Sea fishes in the laboratory. 18 refs., 1 tab.« less