Invasive Species — European Green Crab (Carcinus maenas)
Multiple pathways can introduce the European green crab to new regions. Human-mediated pathways include the aquarium and live food trades, hull fouling, ballast water and aquaculture. Ocean currents and Japan tsunami marine debris are natural pathways that can result in new populations being established.
Genetic analysis of crab from San Francisco, where European green crab were first detected on the west coast of North America in 1989, indicates that founding populations originated from the East Coast. Possible vectors for introduction to the area include dumping seaweeds, used in packing Atlantic seafood products such as lobsters or bait worms, into marine environments and crabs being transported in ballast water.
Of greatest concern to Alaska is the potential for larvae to travel in ocean currents from new infestations in Alaska and established populations in British Columbia into state waters where they could settle out into suitable coastal habitat. European green crabs prefer small protect estuaries and bays, with limited wave action, where eelgrass beds are well established or in saltmarshes. If they are able to successfully establish breeding populations, green crabs could disperse into the many inlets and bays well into southeast Alaska shorelines. Because of Alaskaâ€™s vast size and limited population, it is possible that green crab would become established in remote areas and no one would know for many years.