Soon after the devastating 2011 Tohoku earthquake and tsunami in Japan, debris from across the ocean began washing up on Oregon shores.

A large concrete dock floated ashore near Newport. A derelict fishing boat washed up north of Lincoln City. Other, smaller debris showed up all along the coast and much of it was coated in potentially invasive species of algae, seaweed and other microorganisms.

But now, more than seven years after the quake, experts from Oregon State University say the Pacific Northwest dodged a bullet and none of the invasive species have gained a foothold in the waters off Oregon's coast.

Those findings came in a study published this month in the journal Phycologia.

"When the large concrete dock laden with marine algae and invertebrates washed ashore near Newport, Oregon, some 15 months after the tsunami I was in the parking lot at ODFW discussing the fouling Japanese biota with some of the staff," Gayle Hansen, an Oregon State University algal taxonomist and lead author of the study, said in a statement.

A large concrete dock that floated ashore near Newport on the Oregon coast after the 2011 earthquake and tsunami that rocked Japan.

"They decided it was imperative to remove not only the dock," she continued, "but also all future tsunami debris that washed ashore on Oregon beaches as soon as possible after landing in order to reduce any possible species invasion."

Working with researchers from Kobe University in Japan, Hansen began identifying some of the species, 13 of which are on a worldwide list of invasive species and three—Undaria pinnatifida, Codium fragile subspecies fragile, and Grateloupia turuturu—which are considered particularly hazardous.

"The State of Oregon was able to remove about 90 percent of the derelict and damaged vessels from Japan that arrived along Oregon beaches – and most of the vessels were immediately removed from the surf zone over a period of 24 hours or less," Steven Rumrill of the Oregon Department of Fish and Wildlife, said in a statement.

That strategy of rapid abatement proved successful, said Hansen.

"When the debris materials were removed from the beaches, so was the risk of most of the algal-fouling species colonizing our shore," she said. "Although a large number of the algae were in a reproductive state, their spores typically don't live for very long, or disperse very far, so getting them off the beaches quickly was a smart move."

-- Kale Williams

kwilliams@oregonian.com

503-294-4048