On March 11, 2011, a massive earthquake struck off the coast of Honshu, Japan, creating a tsunami that, in turn, launched a flotilla of debris across the Pacific Ocean. Riding the debris was a small invasion of sea creatures.
A year after the tsunami, with images still vivid of 10,000 people drowned and villages contaminated with radioactivity, a forward-thinking assembly of Oregonians grappled with what to do about the tons of debris anticipated to arrive on Oregon’s shoreline later that year.
There were physical oceanographers from Oregon State University to predict where the currents would deposit the debris. The Coast Guard talked about navigational safety; community leaders and the waste management industry outlined plans for cleaning the beaches.
There were emergency planners, political staff members, education and outreach specialists, park rangers, fishermen, surfers, and beachcombers. There were not, however, any biologists in that conversation. No one gave that angle much of a thought.
Jessica Miller was in her office at OSU’s Hatfield Marine Science Center late on the afternoon of June 4, 2012, when she heard a buzz in the hallway. Apparently, something had washed ashore at Agate Beach, just a few miles north, and it was big.
Curious, she and her husband decided to swing by the beach on their way home. It would be daylight for another couple of hours. “When I got there, I was dumbfounded. It was huge,” said Miller, on first seeing the 66-foot cement dock that had just completed its 5,000-mile journey from Japan. “And then I noticed it was covered with brown algae and big pink barnacles. These creatures weren’t from around here. These were Japanese flora and fauna.”
When she got home, Miller, an ecologist in OSU’s Department of Fisheries and Wildlife, called her OSU colleague John Chapman, who studies invasive aquatic species. They made plans to meet at the marooned dock first thing in the morning.
When Chapman saw the enormous dock covered with living plants and animals, his first thought was, this isn’t supposed to happen. “We invasion ecologists predicted that the tsunami debris would be covered with open-ocean species and that any near-shore Japanese species would be gone by now, after 451 days at sea,” said Chapman.
“The open ocean isn’t a place where near-shore species are supposed to survive. This is changing the way we have to think about invasive species.”
That morning, plans were already in place to completely scrape the Japanese dock before the hitchhiking organisms could escape on the next high tides. Miller and Chapman gathered as many samples as they could, stuffing them in buckets and bags, then taking steps to preserve the specimens for later study.
Precisely identifying all the organisms has turned out to be surprisingly complex. The large pink barnacles were clearly from Japan, but the algae, limpets, and anemones on the dock were similar to some North American west coast species. Over the next several weeks, Miller, Chapman, and OSU botanist Gayle Hansen worked with a dozen taxonomists in the United States, Japan, Russia, and Canada to identify what was on the dock and which species might pose a risk of establishing in Oregon waters.
“To date, we have identified 92 unique species from the dock, of which as many as 10 species are known to be invaders in other parts of the world,” Miller said. “Invasive species do more than just take up residence; they result in ecological or economic damage. And we found some that have the potential to be invasive in Oregon.” The brown algae that Miller first saw that June night turned out to be Undaria pinnatifida, a known invader that can spread rapidly when it gets established. “That’s one I worry about,” she said, noting that the specimens on the dock were reproductive.
The researchers also worry about what other creatures may have already “jumped ship” before the dock hit the beach. And more tsunami debris is heading our way.
Chapman and Miller hope to secure funding to survey coastal waters over the next few years to determine if any of the Japanese organisms become established. The researchers are using a 2010 “rapid assessment” of nearby estuaries as a baseline to know what species were in the estuaries before the dock arrived. But there are no such inventories of near-shore coastal organisms. “Most of the time—but not always—we can identify new invaders in our estuaries if they become abundant and if they are conspicuous,” Chapman said. “Tiny things, including new diseases and parasites, are harder to recognize, even when they invade while we are watching.”
Because the dock was harboring what seemed to be multiple generations of some species that may have successfully bred while onboard their long journey, Chapman guessed that the chance of some of the invaders establishing in Oregon waters is fairly high. Predicting which ones, he says, is all but impossible. “The fact that there were multiple generations indicates they may have been establishing more or less permanent populations while at sea,” Chapman said. “That was unexpected. And it would seem to indicate that this winter’s new debris—if it comes—could be as biologically dangerous as ever.”
The dock landing reflects classic principles of invasion biology, according to Sam Chan, an OSU Extension Sea Grant specialist. “Pathways to invasion are important and the movement of a large coastal structure by tsunami is a new pathway for transporting a large, nearly intact community of organisms across oceans,” said Chan, former director of the Oregon Invasive Species Council. “You would have assumed that organisms have been moving across the oceans for thousands of years, but in reality, this is the first time we’ve witnessed it.”
So, will this invasion succeed?
“Successful invasion is made by repeated ‘hits’ onto the right habitat,” Chan said. “It’s called ‘propagule pressure and habitat suitability.’”
The tsunami and its drifting debris were unwanted tragedies, Chapman said, but there is a silver lining. “The debris provide one of the greatest opportunities to test fundamental ideas of propagule pressure,” he said. “How many invaders does it take to invade? How long can invaders survive as they disperse? Does time matter? What kinds of invaders fail? Scientists over the world have searched for these answers for decades and centuries. This massive, unwanted experiment may answer some of these questions if we give ourselves a chance to look.”