The Observer, May 2008
Heading North?
INVADERS—This European green crab was caught in March off Vancouver Island in British Columbia. Of the approximately 300 crabs taken that day by Canada’s Department of Fisheries and Oceans for research and monitoring purposes, all but two were green crabs, according to Dan Gilson, a citizens’ council project manager who went along to observe. The green crab is an invasive species that has been migrating up the West Coast since the early 1990s and has now reached Canada.
Canadian scientists are finding that the green crabs can shed their shells and grow new ones in water colder than 50 degrees Fahrenheit, a sign they might be able to survive in Prince William Sound if introduced in tanker ballast water. Because green crabs can threaten other species when they invade an area, the council runs its own green crab trapping program in the Sound to detect their arrival, if and when it happens. So far, none have been found. Photo by Dan Gilson