Many sea creatures, such as sponges and shellfish, live in one spot their entire lives. But recently, scientists found that almost 300 typically stationary marine species had traveled nearly 6,920 kilometers (4,300 miles) from home. How? They were carried to the west coast of the U.S. after a record-breaking tsunami. The series of enormous waves had hit Japan in 2011.
When the big waves struck, they washed boats, docks, and buoys into the ocean. Ocean currents then carried the animals living on those objects to North America and Hawaii. A lot of the floating debris was made out of artificial materials, like fiberglass and plastic, that don’t biodegrade, or break down naturally. That allowed the trash—and the hitchhikers attached to it—to make the trip.
The ocean-drifting critters could cause trouble if they thrive in their new home. “The introduction of nonnative predators and competitors can replace or displace native species,” says James Carlton, a marine scientist at Williams College in Massachusetts.