Invasion

Invasion Description

1st Record: CA/San Francisco Bay (1946, Smith 1947, cited by Carlton 1979). From 1999 through 2005, bivalve biomass, including M. senhousia, 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).

Geographic Extent

CA/San Francisco Bay (1946, Smith 1947, cited by Carlton 1979); CA/South San Francisco Bay (Nichols and Thompson 1985b); CA/San Pablo Bay (Nichols and Thompson 1985, cited by Cohen and Carlton 1995); CA/Honker Bay (Nichols and Thompson 1985, Hopkins 1986, cited by Cohen and Carlton 1995); Sierra Point Marina/CA/South San Francisco Bay (2004, Cohen et al. 2005); Coast Guard Island, Oakland/CA/San Francisco Bay (2004, Cohen et al. 2005); Coyote Point/CA/South San Francisco Bay (2004, Cohen et al. 2005); China Camp/CA/San Pablo Bay (2005, Robinson et al. 2011); Rodeo Marina/CA/San Pablo Bay (2004, Cohen et al. 2005); CA/San Pablo Bay (Peterson and Vayssieres 2010, present in dry years); CA/Grizzly Bay (Hopkins 1986, Peterson et al. 2010, present in dry years); Brisbane/CA/South San Francisco Bay (2004, Cohen et al. 2005); Fruitvale Bridge, Oakland/CA/Oakland Estuary (2004, Cohen et al. 2005)); San Leandro Marina//CA/San Francisco Bay (2010, Marrafini et al. 2017); CA/South Francisco Bay (2012-2013, Jimenez et al. 2017, mostly on soft substrates)