California Sea Grant College Program

One of the most ecologically significant invaders in the coastal waters of the U.S.is the European green crab, Carcinus maenas. It is a voracious, generalist predator in its native range in Europe as well as invaded regions which include including South Africa, Australia, Japan, and both coasts of North America (reviewed in Grosholz and Ruiz 1995, Cohen et al. 1995, Geller et al. 1997). Previous work in its native range and in the eastern U.S. has provided much evidence for its strong control over the abundance of benthic organisms in soft sediment communities (e.g. Ropes 1968, Reise 1977, 1985, Morgan et al. 1980, Jensen and Jensen 1985, Tettlebach 1986). Furthermore, work in Bodega Bay Harbor, CA has documented significant changes in the local food web as the direct result of green crab predation: Grosholz et al (2000) found 5- to 10-fold declines in the abundances of previously abundant invertebrate taxa. Lafferty & Kuris (1996) estimated that the annual net value of crab, mussel, oyster, and bait harvests threatened by green crabs in Western North America (WNA) is $43.7 million.