On Monday, June 4, ocean shore visitors reported seeing a loose dock floating offshore near Agate Beach one mile north of Newport, Ore.
The object has since washed ashore and is sitting at the high tide line.
Oregon Parks and Recreation Department staff responded to the site. The dock itself is very large and heavy: 7 feet tall, 19 feet wide and 66 feet long. It is made primarily of concrete and metal, but is clearly designed to float. Because of its size and the chance it could continue to settle or be moved by wave action, state park staff are posting warning tape and signs instructing the public to stay off the structure.
A metal placard bearing Japanese writing was found attached to the dock. The placard was forwarded to the Japanese consulate in Portland, which confirmed that the dock washed ashore on Agate Beach is debris from the March 2011 tsunami in Japan.
Shortly after the dock made landfall, it was checked for radiation and was found to be negative.
Scientists at the Hatfield Marine Science Center in Newport have verified that there is evidence of marine life specific to Japan attached to the dock.
There is some concern about potential invasive species exposure. OPRD is working with Oregon Department of Fish and Wildlife to contain this threat.
Marine organisms removed from the derelict dock were buried landward from the site. ODFW staff and volunteers removed about a ton and a half of plant and animal material. Oregon Parks and Recreation Department staff and a contractor excavated a hole approximately eight feet deep far above the furthest reach of high tides and storm surges. They emptied the bags into it and filled in the hole. Since the organisms require salt water to survive, this disposal method is safe and reliable.
No further action is expected at the site until a decision is made about disposing of the dock, a decision which should be made in the next couple of days. Two basic options are under review: towing it off the beach to a nearby port or harbor, or demolishing it on site and disposing of it in a landfill.
Photos are available at http://www.prd.state.or.us/news.php?id=1603
Oregon Sen. Ron Wyden said, “The huge dock that washed ashore in Agate Beach is clear evidence that debris from last year’s tsunami in Japan is reaching the Oregon Coast much sooner than anyone predicted. This massive dock, which crossed the Pacific Ocean undetected in 15 months, may be the vanguard of more debris to come. With the strong possibility that more debris could pose a significant threat to shipping lanes and fishing grounds, I encourage the National Oceanic and Atmospheric Administration to redouble its efforts in tracking debris generated by the Japanese earthquake and to work closely with other federal, state and local agencies to inform the public how best to report suspected debris.
Scientists at Oregon State University’s Hatfield Marine Science Center said the cement float contains about 13 pounds of organisms per square foot, and an estimated 100 tons overall. Already they have gathered samples of 4-6 species of barnacles, starfish, urchins, anemones, amphipods, worms, mussels, limpets, snails, solitary tunicates and algae – and there are dozens of species overall.
“This float is an island unlike any transoceanic debris we have ever seen,” said John Chapman, an OSU marine invasive species specialist. “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; few came after it was at sea.”
Chapman said it was “mind-boggling” how these organisms survived their trek across the Pacific Ocean. The low productivity of open-ocean waters should have starved at least some of the organisms, he said.
“It is as if the float drifted over here by hugging the coasts, but that is of course 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.”
Jessica Miller, an Oregon State University marine ecologist, said that a brown algae (Undaria pinnatifida), commonly called wakame, was present across most of the dock – and plainly stood out when she examined it in the fading evening light. She said the algae is native to the western Pacific Ocean in Asia, and has invaded several regions including southern California. The species identification was confirmed by OSU phycologist Gayle Hansen.
“To my knowledge it has not been reported north of Monterey, Calif., so this is something we need to watch out for,” Miller said.
Miller said the plan developed by the state through the ODFW and Oregon State Parks is to scrape the dock and to bag all of the biological material to minimize potential spread of non-native species. But there is no way of telling if any of the organisms that hitchhiked aboard the float from Japan have already disembarked in 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.”
The possibilities are many, according to Miller.
“Among the organisms we found are small shore crabs similar to our Hemigrapsus that look like the same genus, but may be a different species,” Miller 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.”
Invasive marine species are a problem on the West Coast, where they usually are introduced via ballast water from ships. OSU’s Chapman is well aware of the issue; for several years he has studied a parasitic isopod called Griffen’s isopod that has infested mud shrimp in estuaries from California to Vancouver Island, decimating their populations.
In 2010, an aggressive invasive tunicate was found in Winchester Bay and Coos Bay along the southern Oregon coast. Known as Didemnum vexillum, the tunicate is 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, according to OSU’s Sam Chan, who chairs the Oregon Invasive Species Council.
It is difficult to assess how much of a threat the organisms on the newly arrived float may present, the researchers say. As future debris arrives, it may carry additional species, they point out. However, this dock may be unique in that it represents debris that has been submerged in Japan and had a well-developed subtidal community. This may be relatively rare, given the amount of debris that entered the ocean, the researchers say.
“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 hope to secure funding to go to Japan and sample similar floats and compare the biological life on them with that on the transoceanic dock.
The scientists say the arrival of the dock is also a sobering reminder of the tragedy that occurred last year, which 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.”
For more information see CBB, May 18, 2012, “Senate’s First Tsunami Debris Oversight Hearing: ‘We All Want To Know What The Plan Is’’ http://www.cbbulletin.com/420573.aspx