On 11 March 2011 an Earthquake off the east coast of Japan measuring 9.0 on the Richter Scale (the fifth most powerful quake ever recorded instrumentally) caused a devastating tsunami which scoured the northeast coast of Hokkaido, destroying numerous communities and killing over 15 000 people. The tsunami also washed vast amounts of debris into the sea, which has been making its way east across the North Pacific ever since.
On 6 June 2012 a 20 × 6 m section of floating dock, identified as having come from the fishing port of Misawa in Aomori Prefecture, washed up on Agate Beach, slightly to the north of Newport, Oregon. The dock weighed approximately 165 tonnes, and was made of concrete an steal with styrofoam floats.
Worryingly it was also covered in about 1.5 tonnes of marine organisms, including kelps, seaweeds, barnacles, muscles, crabs and starfish. This was identified as a threat to local ecosystems by scientists from Oregon State University’s Hatfield Marine Science Center in Newport; unfamiliar species can have unpredictable impacts on ecosystems, sometimes being very harmful. One species identified on the dock was wakame (Undaria pinnatifida), a form of edible Kelp widely farmed in Japan and Korea, but considered a highly aggressive invasive species which has caused severe problems in several parts of the world, notably New Zealand and California.
The dock has been scraped clean and sterilized using torches by volunteers supervised by the Department of Parks and Recreation. It is unclear what its long-term fate will be; it is currently acting as a tourist attraction, but the Department of Parks and Recreation regard it as hazardous and do not seem keen to let it stay.
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