B y the numbers That’s the number of items washed up on American shores that have been traced back to the March 2011 Japanese tsunami. The most recent item was a dock that washed ashore on a remote beach in the Olympic National Park and Olympic Coast National Marine Sanctuary. The dock came from Aomori Prefecture based on a fender production serial number discernible in a photograph. Scientists suspected the dock was from Japan, since then state and federal responders found dozens of plant and animal species on the structure that were native to Japan, not Washington. The dock is the fourth confirmed item found on the shores of Washington. For the latest information on tsunami debris, visit marine debris.noaa.gov/tsunamidebris or marinedebris.wa.gov.