PORTLAND, Ore. -- Large pieces of debris from the other side of the world are still washing up in the Pacific Northwest from a tsunami six years ago.

The debris carries forms of life foreign to our soil.

“A large event like this, so many items, all at once from a known location and place, getting swept out to sea and washing up on shore is unprecedented,” said Brian Steves, who works for the Smithsonian Environmental Research Center and is stationed at Portland State University.

New research has found 300 aquatic species from Japan have invaded American shores. They can cause major problems.

“Ecological damage," said Steves. "They compete against our native species, and they also do a lot of economic damage.”

Steves says the fact that some species are still showing up alive and thriving after years at sea is truly shocking.

“Not only survive but some of these organisms don't have long life spans. So we're talking about multiple generations of the same species, reproducing on say the bottom of a derelict boat, resettling on that boat, and producing another generation until they come ashore, that blew our mind.”

Researchers believe the large amount of plastic swept out to sea has helped keep the critters alive.

“Plastic rafts don't degrade or sink,” said Steves.

Steves says with more and more plastic on coasts and shorelines, the chances of invasive species traversing oceans will continue to grow.

“It could carry whole communities along, so not just a species without its natural prey, but species and their prey items co-existing as they slowly moved across the ocean.”

Steves says researchers are in a detection phase right now. If they discover some of these species have gotten a foothold on our coast and are spreading, eradication might be required. But the process to find out could take months or years.

More; Sea critters hitchhiked across the Pacific on tsunami debris