This project will examine marine organisms arriving on the US West Coast in association with floating marine debris from the March 2011 Tohoku Earthquake and Tsunami in northern Japan. The volume of debris is large and has the potential to inaugurate a massive injection of foreign species. As an example, in June 2012, a single, 20 m-long floating dock dislodged from the port of Misawa on Honshu Island transported nearly 100 Asian species to the coast of Oregon. The PIs propose to gather data on species identity, population structure, reproductive condition, growth histories, genetics, and parasite/pathogen presence from the rafted biota. More than just an assessment of what is arriving, the work will be structured around evaluating a number of parameters important for understanding the potential for long-distance rafting and subsequent invasions. The PIs will also document genetic diversity, providing another perspective on invasions and, where the genes are novel to North America, providing a baseline for examining the spread of novel genes in a new environment. Under most circumstances, the dispersal of adult stages across large expanses of ocean is rare and therefore difficult to study. The large debris field from the tsunami provides a unique opportunity for these studies.
Broader Impacts: Biological invasions are a major driver of community and ecosystem change. The findings of this study will provide valuable information on invasion processes and potential, and in the short term will provide rapid, authoritative information on the species composition, traits, and abundance of invaders associated with the present debris field. The work will include an assessment of parasites and pathogens which could threaten native species.
On March 11, 2011, the Great East Japan Earthquake (Higashi nihon daishinsai), centered in the deep sea off of northeastern Honshu, caused a devastating tsunami that led to the shocking loss of over 18,000 people. Vast coastal destruction of commercial and fishing port facilities, coastal forests, and of hundreds of thousands of homes, was centered in the T?hoku region, that include the prefectures of Aomori, Iwate, Miyagi, and Fukushima. As a result, millions of objects, from both the land and shore, were ejected into the North Pacific Ocean. Part of the resulting debris field resided in nearshore waters of Japan for a length of time before being entrained in ocean currents that began to move the debris north, south, and east, in general describing an exit path from the Western Pacific Ocean toward North America and the Hawaiian Archipelago. Marine-origin debris (such as docks, buoys, floats, ropes, and larger ships) was, or may have been, already biofouled with Japanese species of seaweed (algae), mollusks, crustaceans, worms, and many other animals. Terrestrial-origin debris (such as building lumber, trees, totes and pallets, and small vessels in winter storage) was often colonized by species in nearshore Japan. By the spring and summer of 2012 the first items identified as Japanese Tsunami Marine Debris (JTMD), and with Japanese species aboard, were recognized as having entered the Eastern Pacific Ocean. Particularly notable was the shore landing near Newport, Oregon on June 4, 2012, of a large floating dock (20.1 meters long by 5.8 meters wide by 2.1 meters high) originating from the Port of Misawa, Aomori Prefecture. Aboard were at least 130 living species of Japanese marine animals and plants, including several that were well-known invasive species around the world, as well as many other species not yet known from the Pacific coast of North America. Between 2012 and 2014 our research group studied the biofouling and wood-boring organisms arriving on over 275 JTMD items that were discovered on beaches or at sea between Alaska and California and in the Hawaiian Islands. As of November 30, 2014, over 250 living Japanese marine species had been detected on JTMD, providing an extraordinarily rare opportunity to understand the role of transoceanic dispersal of marine life on a rafted debris field of a known origin and known date of entry into the ocean. Our studies on these species include assessments of reproductive capacity and at-sea reproduction and population renewals of selected species, dispersal trajectories and growth histories, the presence of foreign parasites and pathogens, and genetic studies to refine species identifications and create a barcode database to assist in the detection of possible invasions. Our biodiversity and population analyses demonstrate that the species assemblage, the reproductive state of several taxa, and the growth of a common JTMD species, the blue mussel Mytilus galloprovincialis, varied in relation to the recovery region, indicating that variable transport pathways likely contributed to the generation and maintenance of distinct, robust biotic communities that continue to make landfall along the NE Pacific coast three years after the tsunami. This work unequivocally further demonstrated the presence of genes from three species of mussels, sometimes in combination within individuals. This suggests that JTMD with mussels originate in regions with sympatric populations of, especially, Mytilus galloprovincialis and Mytilus trossulus. Prior to 2012, the regular arrival of living Asian species on marine debris on the North American Pacific coast and in Hawaii was undocumented (the famous "Japanese glass floats" of beachcomber lore carrying primarily native, open ocean gooseneck barnacles). Modern marine debris (including JTMD) consists largely of long-lasting anthropogenic materials (such as fiberglass, plastics, and polystyrene), which may substantially differ from natural substrates (such as tree trunks, branches, and roots) in their at-sea longevity and thus their ability to transport species over long distances. Surveys to determine the status of potential JTMD-related invasions along the Pacific coast and in Hawaii commenced in 2014.
