Here’s a breakdown of the animals that crossed the Pacific on 2011 tsunami debris
About two-thirds of the creatures have never been documented off the western coast of North America
![sea slugs](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2017/10/102817_scivis_feat_free.jpg?fit=860%2C460&ssl=1)
HITCHHIKERS These marine sea slugs stowed away on a derelict vessel from Iwate Prefecture in Japan before being washed ashore in Oregon in April 2015.
John W. Chapman