Invasion:

On June 5, 2012, several thousand castaways rode a massive boxcar-sized dock to landfall on Oregon’s Agate Beach, just north of Newport. A plaque on the side, written in Japanese, revealed an unprecedented journey: The dock had been unmoored from the Japanese coastal city of Misawa during the catastrophic tsunami on March 11, 2011.

The dock and its inhabitants — as many as a hundred species, including mollusks, anemones, sponges, oysters, crabs, barnacles, worms, sea stars, mussels and sea urchins — spent more than a year at sea, drifting 8,000 kilometers across the Pacific Ocean. Within hours of the dock’s discovery, marine biologists from Oregon State University’s Hatfield Marine Science Center were on the scene, identifying species and raising red flags.

“Very quickly we realized we were dealing with a cast of very bad characters,” says John Chapman, an Oregon State University marine biologist who was among the first on the scene. And it was not a small cast: More than two tons of living organisms would eventually be removed from the 20-meter by 6-meter by 2-meter dock. “This was essentially an intact subtidal community of Asian species, aliens fully capable of reproducing, colonizing and invading the Oregon coast,” Chapman says.