Tsunami Debris Heading Towards West Coast Brings Dangerous Invasive Species

A huge debris field is floating towards the United States and will be washing along the western coast of North America over the coming years, bringing with it invasive species, according to the U.S. National Oceanic and Atmospheric Administration (NOAA).

The debris was due to the tsunami in 2011 was the result of the magnitude 9.0 earthquake that struck the east coast of Japan on March 11, 2011. An estimated 5 million tons of debris is said to be moving across the Pacific. While scientists believe up to 70 percent of the debris has sunk to the bottom of the ocean some 1.5 million tons of debris is still heading to North America.

"A significant amount of debris has already arrived on U.S. and Canadian shores, and it will likely continue arriving in the same scattered way over the next several years," NOAA officials said in a statement.

"As we get further into the fall and winter storm season, NOAA and partners are expecting to see more debris coming ashore in North America, including tsunami debris mixed in with the 'normal' marine debris that we see every year," the statement added.

Along with the environmental hazard posed by the tons of debris washing ashore is the realization that some of the most worrisome invasive species could also be brought ashore.

Species that pose the greatest threat include the Northern Pacific sea star, which preys on native species. Another worry is the Japanese shore crab due to its quick reproduction cycle can grow to outnumber native crabs while also consuming the larvae of other native species.

However, Wakame kelp, which is on the list of the 100 worst invasive species around the world, could be regarded as the most potent threat because it grows into large "undersea forests" that can also pose a disruption to "docks, ship hulls, nets, fishing gear, moorings, ropes" while also obstructing sunlight for other marine organisms.