Meeting Abstract
P3.118 Saturday, Jan. 5 A Key To Brachyuran Megalopae of the San Francisco Bay Estuary System GONZALES, Vanessa A.*; TSUKIMURA, Brian; California State University, Fresno; California State University, Fresno vbecer00@csufresno.edu
In 1992, the Chinese mitten crab, Eriocheir sinensis, was discovered in the San Francisco/Delta system. Since its invasion, the Chinese mitten crab has become a nuisance species. If population explosions can be predicted, preparations can be made for the negative effects caused by the down stream migration of mitten crab juveniles. Year-class strength of juveniles may be predicted by megalopae abundance, in correlation with temperature, salinity and tidal currents. Megalopae abundance can be determined with light traps and plankton tows. Presently, there is no mechanism to identify the megalopae species in the San Francisco Bay/Delta system. The objective of this study is to create a dichotomous key of the brachyuran megalopae species of the San Francisco Bay system, thus allowing us to identify and quantitate E. sinensis megalopae. Using characteristics obtained from published literature, a key was generated to identify 13 brachyuran species. Illustrations of each megalopae species was obtained from published literature. Larval light trap samples were obtained from the Smithsonian Environmental Research Center. The light trap samples were taken from areas in the San Francisco Bay/Delta system including Point San Pablo, McNear�s Beach, and Point Pinole Regional Shoreline during March 2007-June 2007. Plankton tow samples taken during January 2006-August 2006, were acquired from the U.S. Fish and Wildlife Service from areas between San Pablo Bay and Suisun Bay. Ten species of Brachyuran zoeae and megalopae were collected from light trap and plankton tow samples and keyed to species to determine abundances. Site Point San Pablo possessed the highest number of E. sinensis megalopae. Eriocheir sinensis megalopae were found in light trap samples taken during April 2007-May 2007.
