Scientists still worry about species tsunami swept from Japan to Oregon

John Chapman of OSU's Hatfield Marine Science Center examines a mussel-encrusted boat from the Japanese tsunami that washed up in Lincoln County. (contributed photo)

CORVALLIS, Ore. - The March 11, 2011, earthquake and tsunami in Japan changed beachcombing in Oregon.

RELATED | 5 years later: Scenes from Japan's 3-fold disaster March 11, 2011

Debris covered in Japanese writing started washing up on Oregon shores.

There were coolers and tubs and canisters and boats.

Perhaps most famously, a massive dock - 165 ton chunk of concrete and steel - washed up on Agate Beach near Newport in June 2012 having made the 5,000 mile journey across the ocean.

It wasn't alone: the dock - and other tsunami debris - crossed the ocean with hitchhikers aboard.

And some of the plants and creatures that crossed the ocean were of concern to scientists: these non-native plants and fish might pose a danger to Northwest waters.

Five years after the disaster, scientists are still uncertain whether any of the more than 200 species that crossed the ocean on tsunami debris have established themselves in the ocean off Oregon, Washington and northern California, Oregon State University said this week.

In the past 3 years, scientists have found barred knifejaws - a fish native to Japan - 4 times.

Mediterranean blue mussels have been ubiquitous on tsunami debris, the university said.

But so far, there's no evidence any of these visitors have put down roots and reproduced ont his side of the ocean.

"Maybe we dodged the bullet, although it is still too early to tell," said John Chapman, an Oregon State University invasive species expert who has investigated tsunami debris along the Pacific coastline. "It is possible that we have not yet discovered these reproductive populations, or that some species from Japan may be cross-breeding with our own species."

One problem: There simply aren't enough resources to search the entire Pacific coast for non-native species, according the Chapman and others.

The 9.0 earthquake and subsequent tsunami were unprecedented in Japan's long recorded history.

Samuel Chan, an expert in aquatic ecosystem health and invasive species with the Oregon Sea Grant program at Oregon State, said the disaster amidst modern civilization is a "new paradigm."

"A tsunami 300 years ago, or even just 60 years ago, would not have created as much marine debris that became a vehicle for moving species across the Pacific Ocean that could become invasive," Chan said. "What makes these major tsunami-driven events different in modern times is the substantial human industrial infrastructure that we have built along the Pacific coast."

The dock that washed up on Agate Beach was the first sign of danger, according to the scientists. It washed up near Newport, home of OSU's Hatfield Marine Science Center.

Scientists found 200 species of plant and animal life on the 66-foot long, 19-foot wide dock.

Chapman and colleague Jessica Miller found Northern Pacific sea stars, Japanese shore crabs, at least eight species of mollusk, an anemone, a sponge, an oyster, a solitary tunicate, three or more species of amphipods, four or more species of barnacles and worms, bryozoans, a European blue mussel known as Mytilus galloprovincialis, and a sea urchin, to name a few.

"We were blown away," he said. "We had always thought these organisms would not be able to survive the long trip across the Pacific Ocean, the middle of which is a biological desert. Yet here they were."

In March 2013, a boat from Japan containing five barred knifejaws washed ashore in Washington state. One of the fish is still on display in the Seaside Aquarium.

A second knifejaw was filmed in a shipwreck near Monterey, California.

A third knifejaw was found trapped in a crab pot near Port Orford, Oregon, in February 2015. Two months later, another was discovered in a boat tank from Japanese tsunami debris near Seal Rock, Oregon.

"Those knifejaws all survived," Chapman said. "Theoretically, the water temperatures north of Point Conception, California, are too cold for them to spawn. But it's hard to know for sure."

Chan and others are still studying what routes the tsunami debris might have taken - and how that may influence the type of organisms found aboard the debris.

"Some species have been discovered that are not native to Japan, and others have not even been identified," Chan noted. "The transponders bobbed around off Japan for some time and then went fairly quickly across the Pacific. But once they arrived here, they moved in and out of near-shore waters, and up and down the coast.

"Satellite tracking of transponders and their discovery by beachcombers indicates that they floated for 2-3 years before they beached on land," Chan added. "The movement patterns of the transponders within the continental shelves of Japan and North American - where nutrients and food are relatively available - could be one piece of a complex puzzle that have allowed these organisms to survive the trans-Pacific journey."

Chan said the work has fostered close collaboration and a shared sense of discovery among Japanese and American scientists.

"The debris still arriving five years later is a reminder that has raised awareness among people - many of whom have been complacent or unaware - about the power and destruction that earthquakes and tsunamis can cause on both sides of the Pacific," Chan said.

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