1st Record: CA/San Francisco Bay (1946, Smith 1946, cited by Carlton 1979). From 1999 through 2005, bivalve biomass, including R. phillipinarum, decreased by 2 orders of magnitude. This was attributed to a cold phase of the El Nino-La Nina oscillation, with increased upwelling and decreased sea-surface temperatures, favoring native cold-water predators, such as shrimp Crangon spp. Juvenile Dungeness crab (Metacarcinus magister) and English Sole (Parophrys vetulus), resulting in increased predation, decreased bivalve biomass and grazing, and resulting blooms of phytoplankton (Cloern et al. 2007).
CA/San Francisco Bay (1946, Smith 1946, cited by Carlton 1979); CA/San Pablo Bay to South San Francisco Bay (Cohen and Carlton 1995); China Camp/CA/San Pablo Bay (2005, Robinson et al. 2011); CA/Suisun Bay (Hopkins 1986); Sherman Island/CA/Sacramento San Joaquin Delta (Hopkins 1986); Brisbane/CA/Brisbane Lagoon, South San Francisco Bay (2004, Cohen et al. 2005); Fruitvale Bridge/Alameda/CA/Oakland Estuary (2004, Cohen et al. 2005); San Mateo Bridge Pylon/CA/ South San Francisco Bay (2004, Cohen and Chapman 2005)
|San Francisco Bay supports dense populations of Ruditapes philippinarum, which have attracted recreational clammers. However, water quality issues have limited harvests (California Department of Fish and Game 2001).|