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New Wave of Tsunami Debris Expected in Pacific Northwest

Researchers watching for potential invasive species

 

A Japanese tote washed ashore at Seal Rock, Oregon, in December 2014 – more than three years after the tsunami that sucked it into the ocean and carried it to Pacific Northwest shores. Photo courtesy of Oregon State University.

Researchers monitoring the seemingly endless stream of debris washing onto Pacific Northwest shores from the tsunami that devastated the northeastern coast of Japan in 2011 won't know the overall cost of dealing with that debris for many more years.

They might never know.

The cost of cleanup alone is monstrous. The possible damage to Oregon's and Washington's fishing, crabbing, shipping and tourism industries remains a major concern, including the potential for invasive species of fauna and flora to hitch a ride aboard the debris and usurp native species – a process that might not show up for as long as 20 years, researchers say. So far, researchers have documented more than 200 different "illegal immigrant" species that have made the trans-Pacific trek as unintended hitchhikers.

Whether or not they have established themselves anywhere remains unknown.

John Chapman, an Oregon State University (OSU) marine invasive species specialist at OSU's Hatfield Marine Science Center (HMSC), is leading Oregon's efforts to identify the alien invaders.

In spring 2014, about 30 fishing vessels from Japan washed ashore along the Pacific Northwest coast – many of them covered in live organisms indigenous to Asia. Chapman and OSU colleague Jessica Miller examined roughly a dozen of those boats that washed ashore in various locations from the southern Oregon coast to the central Washington coast. Most were long, narrow skiffs up to 30 feet in length, with no motors. As they drifted from Asian waters to the Pacific Northwest coast, they picked up a variety of organisms along the way.

Chapman said blue mussels were found on literally every boat that has washed ashore. "The crustaceans and bivalves are of particular concern because they could introduce new diseases, and compete with, displace or otherwise affect our oyster or mussel populations," he noted.

The flow of wayward skiffs and other tsunami debris ebbed sharply during the summer due to seasonal wind shifts. With wind and ocean currents returning to their usual winter-spring patterns, Chapman and other scientists expect more items to wash ashore.

In December 2014, a tote with numerous mussels clinging to it washed up at Seal Rock, Oregon - the Ghost of Debris-Yet-to-Come. More objects will arrive during the next few months, and researchers are most concerned about boats and other large objects carrying a variety of living organisms, although they don't expect to see anything the size or scope of the 66-foot section of concrete floating dock that grounded on Agate Beach near Newport, Oregon, in 2012.

When the tsunami debris first began to arrive, it brought fears of possible radiation and chemical contamination.

The massive dock had no traces of radiation, but OSU-HMSC researchers did find the completely different threat of invasive species. An estimated 100 tons of organisms – about 13 pounds per square foot – were clinging to it. Dozens of species of barnacles, sea stars, urchins, anemones, amphipods, worms, mussels, limpets, snails, tunicates and algae hitched a ride, although Chapman considered it "mind-boggling" that the plants and creatures survived the trek across the Pacific Ocean.

He called the dock "an island unlike any transoceanic debris we have ever seen," noting that drifting boats lack such dense fouling communities. Nearly all of the species they examined were established on the dock before the tsunami. Few attached to it while at sea. The low productivity of open-ocean waters should have starved at least some of the organisms, but the plethora of organisms aboard the dock led Chapman to surmise that life for those organisms while drifting on the open ocean "may be more gentle than we initially suspected."

"We've been surprised at the tenacity of some of these coastal Asian organisms that are arriving on the tsunami debris because the middle of the ocean isn't the most biologically productive place for coastal species," Miller said.

She said they found brown algae commonly called wakame - native to the western Pacific Ocean in Asia - across most of the dock.

She said wakame has invaded several regions, including southern California, and while it has yet to spread north of Monterey, California, it is "something we need to watch out for." Once established, say researchers, eradicating or controlling it is nearly impossible. One wakame plant produces enough spores to establish a colony, but researchers don't believe it has established itself in Oregon waters.

Oregon Department of Fish and Wildlife and Oregon State Parks scraped the dock in Newport and bagged all of the biological material to minimize potential spread of non-native species. But researchers had no way to tell whether any of the hitchhiking organisms aboard the dock had already disembarked in nearshore waters.

Chapman said it would take time to find out if any unwanted guests have moved in. But the Oregon coast is vulnerable. One new introduced species is discovered in Yaquina Bay at Newport on Oregon's central coast every year.

"We hope that none of these species we are finding on this float will be among the new discoveries in years to come," he noted.

The possibilities, however, are many.

"We continue to find new organisms that we have never seen before," Chapman said. "There isn't as much diversity aboard the Japanese fishing vessels as there was on the dock, but each new species we haven't seen before is a cause for concern. No one can predict if these new species may gain a foothold in Northwest waters – and what impacts that may have."

Among some of the species the Oregon State biologists have encountered during the past year are bat stars – sea stars that look like they have bat wings, striped knifejaw found alive in at least one boat, and numerous small crustaceans.

Teams of scientists from around the North Pacific region, including Chapman and Miller, identified more than 165 species aboard the Agate Beach dock, and found another 40-50 species on other debris items, including the boats. The rate of incoming debris should ebb, researchers say, but the arrival of so many boats last spring shows it's not over yet.

Debris was initially projected to show up periodically for five years.

A number of ports and harbors in Washington, Oregon and California spent huge amounts of time and money to repair damage and clear away debris in the aftermath of the tsunami waves that rippled across 4,500 miles of ocean from Japan to wreak havoc along the Pacific coast in March 2011. Marine debris is a perennial problem anyway on Pacific shores, requiring frequent beach cleanups to remove tons of detritus.

Invasive marine species are also a problem on the Pacific Coast, where they are generally introduced via ballast water from ships.

Chapman is well aware of the dangers posed by invasive species. For several years, he has studied a parasite called Griffen's isopod that has infested mud shrimp in estuaries from California to Vancouver Island, decimating their populations. And an aggressive invasive tunicate found in 2010 in Winchester Bay and Coos Bay along the southern Oregon coast is on the state's most dangerous species list as both an ecological and economic threat due to its ability to spread and choke out native marine communities.

Since Chapman and Miller first examined the Agate Beach dock, they have examined a similar dock that beached in northwestern Washington, as well as numerous boats and more than three dozen other large debris pieces. Some pieces carry organisms found only in Asia. While few species on the debris are exclusively native to the Pacific coast, several species are found in both locations.

Which of the species originating in Asia, if any, becomes established in the Pacific Northwest – and what potential damage there may be ecologically and economically – is nearly impossible to anticipate, they noted.

The OSU researchers are working with other Pacific coast scientists, attempting to genetically identify all of the species arriving on tsunami debris using genomic sampling – work led by Jon Geller of Moss Landing Marine Laboratory. Geller and his students are collecting samples of marine life in Northwest coastal and estuary communities searching for any evidence of non-native species establishment.

"We're also doing a lot of old-fashioned looking," Chapman said. "But new species can be difficult to identify if you aren't searching for them directly in the first place."

"Ecologists have a terrible track record of predicting what introduced species will survive and where," he added. "The real question for scientists who study these species is the big picture view – how do things get introduced into a new location and move around the world? The Japanese tsunami was a terrible tragedy and the debris that is arriving is certainly an unintended consequence. But it is providing us with an unprecedented experiment on species introduction."

"We're observing more 'settlement' on these debris items that appears to have occurred soon after the tsunami," said Miller. "We are trying to improve our understanding of the mechanisms that allow organisms to disperse across the ocean."

The researchers say that some of the Asian aquatic species that hitchhiked aboard the tsunami debris might have reproduced during their trans-Pacific journey. If so, it's possible they could have released gametes into local coastal waters, which boosts the chances of establishing themselves and turning into invasive species.

Once established, those species could potentially breed with similar local species and create hybrid organisms, the researchers noted.

Oregon State University researcher and invasive species expert John Chapman examines a mussel-encrusted boat from Japan that washed up on a beach near Newport, Oregon. Chapman and others are prepping for another wave of debris to wash ashore from the earthquake-spawned tsunami that struck Japan in 2011. Photo courtesy of Oregon State University.

Researchers aim to quantify the species arriving on tsunami debris, assess their abundance, and characterize the organisms morphologically and genetically. They also are examining the species' reproductive state and looking for parasites on host organisms. And they say the risk of non-native species hitching a ride aboard the debris becoming invasive remains very real.

How much of an impact invasive species might have in years to come remains one of those scientific riddles wrapped in a mystery inside an enigma, waiting to reveal itself in due time.

"From day one, we've been asked which species we should be worried about," Chapman said. "The answer is just not that simple. We cannot predict which starfish or algae species poses the biggest threat – but we know that invasions in general are bad. We just don't know which of them, if any, will turn out to be a problem five, 10 or 20 years down the road. We do know that the rate of new, introduced species discoveries has increased exponentially over the last hundred years. More are coming."

Miller agreed. "It is safe to say that we are still concerned that some of these non-native species could establish themselves along our coast," she said. "And the potential ecological impacts could be significant."

 
 

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