Plastics and metals have made it much easier for invasive species to raft across oceans.
September 29, 2017 — On March 11, 2011, an unprecedentedly powerful earthquake struck the Tōhoku region of Japan. It destroyed hundreds of thousands of buildings, wrecked the Fukushima Daiichi nuclear plant, created a tsunami that reached 40 meters in height, and shifted the entire planet a few inches on its axis. But among these catastrophic consequences, there were also subtler ones. For example, the tsunami inundated a small blue-and-white fishing boat called the Sai-shou-maru, ripping it from its moorings and casting it out to sea.
The boat drifted eastward through the Pacific, never capsizing. Then, on March 22, 2013, a couple weeks after the two-year anniversary of the quake, it washed ashore on Long Beach, Washington. Its hull was encrusted with seaweed and barnacles, and one of its compartments was full of water. And living in that water were five striped beakfish. The fish were youngsters, just four inches long. They had probably been swept into the boat as larvae, and spent their entire lives growing up within this ersatz aquarium. For two years, the boat was their entire world.
Four of those fish were euthanized by the Washington Department of Fish and Wildlife, but the fifth—now known as the “tsunami fish” was relocated to Oregon’s Seaside Aquarium. Its story astonished John Chapman, an ecologist at Oregon State University who studies aquatic invasive species. Somehow, this coastal species had endured a two-year, 4,000-mile voyage across the open ocean, in the tiniest of living spaces. “We said this couldn’t happen,” Chapman told OregonLive. “And nature is like: Oh yes it can.”
Of late, nature has been saying that to Chapman a lot.
In the last five years, he and his colleagues have documented 634 pieces of debris that were swept away by the Tōhoku tsunami and eventually washed up on the coasts of North America. And it hasn’t stopped coming yet. Between them, these bits of ocean-hopping junk carried 289 species that are typically found along Japanese coasts—a vast horde of sponges, sea stars, sea anemones, mussels, limpets, barnacles, and fish.