Countin’ Crabs at Seadrift Lagoon
by Ryan Greene, science writing intern
European green crabs (Carcinus maenas) caught in Seadrift Lagoon (Stinson Beach, Calif.). Credit: Ryan Greene/SERC
The Smithsonian Environmental Research Center’s (SERC) largest west coast outpost, SERC-West, sits on San Francisco Bay in Tiburon, California. SERC’s main campus is 2,000+ miles away on the Chesapeake Bay in Maryland. In an attempt to bridge this distance, we’ve launched “Tidings From the Sunset Coast,” a summer series highlighting the work at SERC-West. Our most recent story was a spotlight of our summer interns. This post is about the invasive European green crabs in Seadrift Lagoon, just north of San Francisco. Enjoy!
How many crabs are in the lagoon? This question may sound like the middle-school carnival contest of how many jelly beans are in the jar. But for ecologists at SERC-West, it’s no guessing game—the health of an ecosystem hinges on the answer.
Seadrift Lagoon is about 20 miles north of San Francisco Bay, and it’s said to have the highest density of European green crabs on the West Coast. Credit: Ryan Greene/SERC
Since 2009, Smithsonian scientists have partnered with the University of California, Davis, and Portland State University to tackle a two-clawed problem in Seadrift Lagoon: Carcinus maenas, the invasive European green crab. Seadrift is a small subdivision surrounding an artificial lagoon that sits smack between the Pacific Ocean and Bolinas Lagoon at the northern tip of California’s Stinson Beach. In the early 1990s, green crabs began to take up residence here, and since then they’ve done their fair share of damage.
The primary problems with green crabs in Seadrift are that they’re hungry and there are scads of them. This lagoon houses the highest density of green crabs documented on the West Coast, and they eat a whole lot. In nearby sites, like Tomales Bay and Bodega Bay, green crabs have caused native bivalve populations to plummet, and in some cases they have edged out other native crabs. In Seadrift, the sheer number of green crabs suggests that the impact on the ecosystem may be similarly drastic. That’s why in 2009, scientists at SERC-West, UC Davis, and Portland State started working with community members and citizen science volunteers to remove the crabs from the lagoon. Click to continue »