By Terry Dillman
A dock as big as a good-sized commercial fishing vessel washed shore in Agate Beach near Newport, Oregon on June 4, and has since caused quite a stir among scientists, government officials and curiosity seekers.
It also brought potential implications for Pacific Northwest commercial fisheries.
The 165-ton steel-and-concrete dock float – one of four ripped from their moorings at the Port of Misawa by the massive tsunami that inundated Japan in March 2011 – teemed with non-native plant and animal marine species, known collectively and colloquially as invasive species.
How the gigantic piece of flotsam – 66 feet long, 19 feet wide, and seven feet high – rode the waves and currents for several thousand miles undetected until it neared Oregon’s central coast is a riddle wrapped in a mystery inside an enigma. The tsunami marine debris coordinator for the National Oceanic and Atmospheric Administration (NOAA) said even something that size floating amid the currents, winds and waves of the vast Pacific Ocean is quite difficult to monitor, even with satellites.
Whether it’s an anomaly or a harbinger of what lies ahead for Pacific Northwest shores as an estimated 1.5 million tons of tsunami debris wends its way across the ocean on the whims of wind and currents also remains uncertain. But such debris poses a certain threat for a number of reasons.
Commercial fishery leaders worry about the size and distribution of debris in terms of navigational hazards and equipment entanglement. Other issues are the possibility of radiation (although NOAA officials said the chances are slim to none) and chemical contamination. Then there are the potential costs of cleaning up tons of debris. But the dock’s June 4 arrival focused attention on another clear threat: alien flora and fauna.
The first hint that the dock had journeyed from Japan was found in a species of algae indigenous to Asia, including Japan.
Jessica Miller, an Oregon State University (OSU) marine ecologist, said brown algae commonly known as wakame covered much of the dock. She said the algae is native to the western Pacific Ocean in Asia, and has invaded several regions including southern California. OSU phycologist Gayle Hansen confirmed the species identification.
The examination by scientists uncovered a plaque bolted to the dock commemorating its June 2008 installation. The Japanese consulate in Portland, Oregon traced its origin to the Aomori Prefecture on the northern tip of Japan’s coast. Used for loading fish into trucks, the dock is one of four the titanic tidal wave carried out to sea. Japanese officials say one showed up a few weeks later on an island south of Misawa. The other two are still missing.
Scientists at OSU’s Hatfield Marine Science Center (HMSC) said millions of organisms hitched a ride aboard the ersatz island that beached on Oregon’s central coast – dozens of species of barnacles, starfish, urchins, anemones, amphipods, worms, mussels, limpets, snails, solitary tunicates and algae.
John Chapman, an OSU marine invasive species specialist, called the organisms’ survival of their trek across the Pacific Ocean “mind-boggling,” noting that the low productivity of open ocean waters should have starved at least some of them. “It’s as if the float drifted over here by hugging the coasts, but that’s impossible,” Chapman said. “Life on the open ocean, while drifting, may be more gentle for these organisms than we initially suspected. Invertebrates can survive for months without food, and the most abundant algae species may not have had the normal compliment of herbivores. Still, it is surprising.”
Chapman said the float “is unlike any transoceanic debris we have ever seen. Drifting boats lack such dense fouling communities, and few of these species are already on this coast. Nearly all of the species we’ve looked at were established on the float before the tsunami. Very few came after it was at sea.”
Invasive marine species are already a major problem on the West Coast, where they usually are introduced from ship ballast water.
Chapman is well aware of the issue, having for many years studied a parasitic isopod infesting and decimating mud shrimp populations in estuaries from California to Vancouver Island, with potentially dire consequences for the health of those estuaries. In 2010, an aggressive invasive tunicate appeared in Winchester Bay and Coos Bay along the southern Oregon coast. It’s on the state’s most dangerous species list and is both an ecological and economic threat because of its ability to spread and choke out native marine communities, said OSU’s Sam Chan, chair of the Oregon Invasive Species Council.
Researchers say it’s difficult to assess how much of a threat the newly arrived organisms represented. And there was no way they could tell if any of the hitchhikers aboard the float had already moved into nearshore waters.
“We have no evidence so far that anything from this float has established on our shores,” said Chapman. “That will take time. However, we are vulnerable. One new introduced species is discovered in Yaquina Bay, only two miles away, 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.”
Possibilities are many and varied.
“Among the organisms we found are small shore crabs similar to ours that look like the same genus, but may be a different species,” she said. “There were also one or more species of oysters and small clam chitons, as well as limpets, small snails, numerous mussels, a sea star and an assortment of worms.”
As future debris arrives, it could bring additional species, they noted. Yet this dock could also be unique, because it is debris that was submerged in Japan and had a well-developed sub-tidal community. Researchers say that this situation could prove relatively rare, given the amount of debris that entered the ocean.
“Floating objects from near Sendai can drift around that coast for a while before getting into the Kuroshio current and then getting transported to the eastern Pacific,” Chapman said. The researchers want to find funding to go to Japan to sample similar floats and compare the biological life on them with that on the transoceanic traveler that ended up on Agate Beach.
State officials took no chances, following procedures designed to minimize potential spread of non-native species.
Personnel from Oregon State Parks and the Oregon Department of Fish and Wildlife scraped away all plants and animals from the dock onto a tarp, stuffed them into large plastic garbage bags and buried it all in an eight-foot deep hole beyond the reach of high tides and storm surges. Without saltwater, the plants and animals cannot survive, officials noted. They used propane torches to sear any remaining traces of life still clinging to the dock float.
As of press time, two options were under review for taking care of the dock itself: either towing it off the beach to a nearby port or harbor or demolishing it onsite and disposing the remains in a landfill.
One major question remained. If a piece that size could show up far sooner than scientists expected, what lies ahead?
Flotsam and Jetsam
The Japanese government estimated that the 2011 tsunami washed about 5 million tons of debris into the ocean, 70 percent of which quickly sank. Every year, tons of flotsam coagulate into swirling trash heaps – dubbed “garbage patches” by oceanographers – within ocean gyres (locations where the water spins like a whirlpool without the downward spiral; they just sit and spin). Recent monitoring indicates that at least some of the tsunami debris would pull away and get caught in one of those north Pacific gyres.
NOAA monitored the debris field for about a month before it dispersed too widely for satellites to track. Initial tracking had the 1,000-mile debris trail traversing the sea at a rate of about 10 miles per day.
Scientists aren’t sure how much of the remaining 1.5 million tons is still afloat. Using computer models, NOAA researchers believed that most of the remaining debris wouldn’t reach the Pacific Northwest coast until next year. Using today’s form of “dead reckoning” – computer modeling of winds and currents – scientists say most of the debris that survives the journey would likely strike Oregon and Washington in 2013 and 2014, despite concerns about flotsam invasions as early as autumn 2012. Much of it, they said, might never get here.
Most still stick with that assessment, although winds, currents, tides and waves can alter the equation.
During a briefing in January at HMSC, representatives from NOAA, Oregon Parks and Recreation Department, OSU, local emergency management agencies and others outlined the situation for Sen. Ron Wyden (D-Ore.).
The unexpected arrival of the behemoth float prompted Wyden to renew his call for NOAA and other federal and state agencies to enhance efforts to track the debris, noting the danger such big pieces pose to sea traffic, including commercial fishermen. Safety at sea and on shore is the primary concern.
It prompted Wyden to urge officials to develop a response plan that “prepares for the worst while hoping for the best” in a letter to NOAA Administrator Jane Lubchenco. “Because the potential for damage to Oregon’s fishing, crabbing, shipping and tourism industries is a major concern, it is vital that federal, state and local agencies and outside organizations work together to get ahead of this issue,” he wrote. “This kind of broad-scale cooperation and coordination at every level is crucial to minimizing overlap and ensuring that accurate information is available to everyone who could come in contact with this debris, be it on water or on the beaches.”
The float was the second-largest piece of flotsam to show up from the tsunami. The waves dislodged the 164-foot shrimping vessel Ryou-Un Maru from its mooring in Hokkaido, Japan, where it awaited scrapping. The unmanned vessel drifted across the Pacific Ocean until the US Coast Guard sank it in April in the Gulf of Alaska after deciding it was a threat to shipping and the state’s coastline.
The scientists said the dock float’s arrival is also a sobering reminder of the 2011 tragedy that cost thousands of lives.
“We have to remember that this dock, and the organisms that arrived on it, are here as a result of a great human tragedy,” Miller said. “We respect that and have profound sympathy for those who have suffered, and are still suffering.” ]