Meeting Abstract

P2.19  Monday, Jan. 5  Eriocheir sinensis megalopae abundance in regions of the San Francisco Bay Estuary GONZALES, Vanessa A.*; TSUKIMURA, Brian; California State University, Fresno; California State University, Fresno vbecer00@csufresno.edu

Little is known about the population dynamics of the megalopa stage of the Chinese mitten crab, Eriocheir sinensis, in the San Francisco Bay estuary. The aim of this study was to determine megalopa abundance in regions of the San Francisco Bay estuary. Megalopae abundance may be determined by the use of light traps. Larval light trap samples were obtained from the Smithsonian Environmental Research Center. The light trap samples were deployed biweekly in areas of the San Francisco Bay/Delta system including Point San Pablo, McNears Beach, and Point Pinole Regional Shoreline during March 2007 – June of 2007. Light trap samples were deployed biweekly during March – July of 2008 from sample sites including Point San Pablo, Point Pinole Regional Shoreline and Point Molate. Previously, a dichotomous key was made for the brachyuran megalopae of the San Francisco Bay, thus allowing us to identify and quantify E. sinensis megalopae in light traps samples taken from the bay in 2007 and 2008. Site Point San Pablo was the only sampling site where E. sinensis megalopae were found. E. sinensis megalopae were found in light trap samples taken during April 2007 – May of 2007 and May of 2008. Almost all megalopae were found in the month of May. For 2007, all E. sinensis megalopae were found in samples taken on the day after the new moon. For 2008, E. sinensis megalopae were found in samples taken on the day of the full moon. It is possible that E. sinensis megalopae use lunar cycles to disperse to areas that are more suitably for settlement and metamorphosis. However, given the minimal amount of data collected in this study, further research would have to be done to support this hypothesis.