Now six years on, the earthquake and tsunami that devastated Japan, is also causing ecological waves in Hawaii and North America’s Pacific coast. In 2011 a massive earthquake jolted Japan causing the seafloor to uplift by 30 feet. In addition to the destruction, the tsunami swept 5 million tons of debris into the ocean, much of it non-biodegradable. Fiberglass boats, buoys, domestic plastic items, even a 60 ft long concrete and polystyrene dock are just some of the items that have floated over 4,000 miles across the ocean.
With these items came a host of sea creatures native to Japan – mostly invertebrates like mussels, oysters, starfish, nudibranchs, amphipods, isopods, bryozoa, barnacles, anenomes, and crabs, but also two fish species as well. A study by invasive species expert James T Carlton, published recently in Science, documented 289 living Japanese coastal marine species from 16 phyla have arrived to the shores of North America. “Rafting” is actually-well acknowledged vector for the transport of invasive species, and this is the longest documented transoceanic survival and dispersal of coastal species by rafting ever recorded.
Japanese tsunami marine debris, became known as JTMDs, have been found from Sitka, Alaska, down to Monterey, California. Of the species that travelled with the debris, about one third was already present on the Pacific coast. So, the question remains whether the remaining two thirds can survive. Then, of those which can reproduce and establish self-sustaining population. Further still, of those that establish, which will have negative affects on their invaded ecosystems and the species within them.
Rafting, as mentioned earlier is not a new phenomenon. The difference is now that instead of invaders travelling on/in/attached to wood, which can degrade, they are rafting over with non—biodegradable plastics. Carlton believes the rafting will continue, for at least the next 10 springs to come.
Please see the original publication
http://science.sciencemag.org/content/357/6358/1402
Carlton, J.T., Chapman, J.W, Geller, J.B., Miller, J.A., Carlton, D.A McCuller, M.I. (2017) Tsunami-driven rafting: Transoceanic species dispersal and implications for marine biogeography. Science. 357: 1402-1406.
