BAUER, D. K.*; RUDNICK, D.; CULVER, C.; VELDHUIZEN, T.; TULLIS, R.; HIEB, K.; TSUKIMURA, B.; California St. Univ., Fresno; 10,000 Years Insitute; University of California, Santa Barbara; California Dept. of Water Resources; California St. Univ., Hayward; California Dept. of Fish and Game; California St. Univ., Fresno; : The life history of Eriocheir sinensis in the San Francisco Bay

The recent invasion in 1992 of Eriocheir sinensis, the Chinese mitten crab, into the San Francisco Bay and the Sacramento-San Joaquin Delta Waterways provides an opportunity to examine the factors driving this invasive specie� population dynamics. Throughout its worldwide distribution, mitten crab populations have shown dramatic oscillations in abundance. The ability to predict abundance before a major population increase will improve management of the population crush. Toward this end, a life history model has been developed from the scientific literature and recent research. Juvenile crabs move upstream to freshwater areas where they develop into adults. Growth rates indicate that this process requires a minimum of one year, and up to 3 additional years depending on environmental conditions. Environmental signals appear to stimulate gonad development that is followed by a downstream migration at the end of summer. Mating occurs in saline water, where females ovoposit and fertilize eggs. Embryos are carried to hatching, and larvae undergo 5 zoeal stages before settlement. Our model is based on larval growth at various temperatures and suggests that juveniles migrate to freshwater in their second year. Our model predicts that most mitten crabs spend three years in freshwater prior to their downstream migration. Research is continuing to link environmental conditions with year class strength of this important invasive species. [Support by the California Sea Grant College Program Grant NOAA NA06RG0142 2003-05, and California Water Institute CSU Fresno, #20058]