Abstract
The 2011 East Japan earthquake generated a massive tsunami that launched an extraordinary transoceanic biological rafting event with no known historical precedent. We document 289 living Japanese coastal marine species from 16 phyla transported over 6 years on objects that traveled thousands of kilometers across the Pacific Ocean to the shores of North America and Hawai‘i. Most of this dispersal occurred on nonbiodegradable objects, resulting in the longest documented transoceanic survival and dispersal of coastal species by rafting. Expanding shoreline infrastructure has increased global sources of plastic materials available for biotic colonization and also interacts with climate change–induced storms of increasing severity to eject debris into the oceans. In turn, increased ocean rafting may intensify species invasions.
 |
| Marine sea slugs from a Japanese vessel from Iwate Prefecture, washed ashore in Oregon in April 2015.
photo: John Chapman
|
 |
| A vessel carried by the Japanese tsunami washed ashore in Oregon, coated in gooseneck barnacles that colonized the boat as it floated across the North Pacific. Several Japanese species also survived the voyage, in the crevices inside and underneath the boat.
photo: John Chapman
|
James T. Carlton, John W. Chapman, Jonathan B. Geller, Jessica A. Miller, Deborah A. Carlton, Megan I. McCuller, Nancy C. Treneman, Brian P. Steves and Gregory M. Ruiz. 2017. Tsunami-driven Rafting: Transoceanic Species Dispersal and Implications for Marine Biogeography. Science. 357(6358); 1402-1406. DOI: 10.1126/science.aao1498
Tsunami enabled hundreds of aquatic species to raft across Pacific phy.so/425798070 via @physorg_com
Long-distance life rafting:
When coastal ecosystems are affected by storms or tsunamis, organisms can be rafted across oceans on floating debris. However, such events are rarely observed, still less quantified. Carlton et al. chart the rafting journeys of coastal marine organisms across the Pacific Ocean after the 2011 East Japan earthquake and tsunami (see the Perspective by Chown). Of the nearly 300 mainly invertebrate species that reached the shores of the U.S. Pacific Northwest, most arrived attached to the remains of manmade structures.
