Mapping Japanese Tsunami Debris and Marine Invasions: Understanding Natural Disasters and Implications of New Species

It was 2:45 p.m. on March 11, 2011, when the Tohoku region of Japan was hit with a magnitude 9.0 undersea earthquake, the most powerful earthquake to have ever hit Japan and fourth most powerful in the world, resulting in a catastrophic tsunami and meltdown of  three nuclear reactors in the Fukushima Daiichi power plant.  

The tsunami continued across the Pacific, bringing surges up to 8 feet that caused extensive damage along the United States’ western coastline. Nearly four years after the initial tragedy the impacts are still being felt, but in unexpected ways. Five million tons of inland and coastal debris – mostly non-biodegradable plastic, fiberglass, and foam ranging in size from bottles and buckets to entire boat hulls and harbor docks – was swept into the Pacific Ocean by the tsunami and turned into floating ecosystems in the subsequent months, acting as the hosts for a multitude of seaweeds, barnacles, crabs, clams, oysters, fish, and worms. By 2012, some of this began to make landfall on Hawaii, Alaska, and the beaches of the West Coast. Never before had marine organisms traveled from Japan to North America in the open ocean and survived, or at least this was never recorded in scientific or historical literature, according to James Carlton, a world-renowned researcher specializing in aquatic invasive species.

This is an event so rare, we simply don’t expect to see it,” said Carlton in a news article published in Nature.

Within months of the earthquake, hundreds of new species – some in healthy condition – had been introduced into Canadian and U.S. waters. This prompted many marine biologists to begin observing potentially new invasive species that could disrupt habitat, influence predator-prey relationships, and impact human activity on coasts when placed in the right conditions.

“In the big picture, any species that comes in is going to consume resources, occupy space, and probably will have some impact on other species or on its prey,” said Carlton.

As a professor emeritus of marine science at Williams College and director emeritus of the Williams College Maritime Studies Program at Mystic Seaport, Carlton and his colleagues have been studying the survival, dispersal, and genetic characterization of the marine life discovered on Japanese tsunami debris with funding from Oregon Sea Grant, as well as the the National Science Foundation, and the Japanese Ministry of the Environment.

Beach-goers at Agate Beach in Newport, Oregon inspect an 180-ton dock that washed ashore one year after being torn from the city harbor of Misawa, Japan during the 2011 tsunami disaster. Photo courtesy: State of Oregon

Beach-goers at Agate Beach in Newport, Oregon inspect an 180-ton dock that washed ashore one year after being torn from the city harbor of Misawa, Japan during the 2011 tsunami disaster. Photo courtesy: State of Oregon

“Oregon was the first to encounter debris and new species, which were never documented in the area before, and were identified as endemic to Japan, or that region of the Pacific,” said Sam Chan, watershed and invasive extension specialist for Oregon Sea Grant, who is working with the California, Washington, Alaska, and Hawaii Sea Grant programs to devise new management strategies for marine debris.

“Jim [Carlton] is one of the frontrunners in understanding this new pathway [for invasives] from natural disasters with human and coastal development elements,” he said, explaining that with increased development along coastlines there will be more damage and debris resulting from natural disasters: “A symptom of modern times.”

Knowing the details of when the Japanese tsunami debris entered the Pacific Ocean and from what locations has given Carlton and other scientists a unique opportunity to gain insight on how debris travels, and how invasive species might interact in the open ocean.

“Jim’s work highlighted the impacts of debris, and got people thinking about natural disasters, the topic of marine debris, and coastal hazards,” said Chan in reference to invasive species as a secondary issue of marine debris. “It wasn’t something that happened far away. It impacted us here as well.”

Sea Grant-supported workshops helped to develop new protocols established under the NOAA marine debris program to guide response efforts, clean-up initiatives, and debris assessments to reduce possible impacts to our natural resources and coastal communities.

It is estimated that the state of Oregon would need between $1.5 million and $5.5 million in funds to remove Japanese tsunami debris from its shores, according to Oregon Sea Grant, demonstrating the importance of addressing marine debris in coastal management plans.

East Coast Invasions

While tsunami debris has presented a new pathway of travel for invasive species that are impacting the West Coast, Carlton is also investigating invasive species along the East Coast, which are suspected of having arrived through more traditional modes of travel via ballast water, which is often coastal water taken at one port to help stabilize oceangoing vessels and discharged at the next port of call.

“There’s a widespread perception that marine biologists know about all the things along the coast,” Carlton noted. “But in fact, the evidence often speaks otherwise.”

shrimp2

Palaemon macrodactylus (Asian shrimp) collected near Mystic Seaport.

The Asian/Oriental shrimp (Palaemon macrodactylus) and the British prawn (Palaemon elegans) have been observed in New England waters, yet their impact on the local environment is not entirely understood.

“These are large shrimp, often 2 to 3 inches long, and they are fairly distinctive,” Carlton said. “Both species arrived, became somewhat widespread, and nobody noticed.”

Judy Pedersen, an invasive species expert and research affiliate at MIT Sea Grant, reiterated this point, saying, “too often species such as the newly arrived shrimp are not noticed or taxonomically identified as non-natives, yet they are or may impact local communities.”

First discovered in the Bronx River, N.Y., in 2001, the Asian shrimp has now expanded as far north as Maine, and as far south as central New Jersey. In contrast, the British prawn was not detected in North America until 2010 during an Asian shrimp survey in Massachusetts. So far this species has yet to be detected south of Cape Cod, though Carlton expects to see it in Narragansett Bay in the near future.

“These species will expand. They will respond to climate change, and other species could appear as well,” he said.

In 2014, Carlton led a team focused on creating a rapid assessment of native and invasive shrimp populations from Canada to New Jersey, surveying 63 sites, including Fort Adams and Point Judith Marina in Rhode Island, to better understand if and where the ranges of these populations were shifting.

Dr. James Carlton with student collecting dock samples at Mystic seaport to identify presence of Asian shrimp.

Dr. James Carlton and Williams College-Mystic Seaport Maritime Studies Program intern Hugh Cipparone collect dock samples near Mystic Seaport to identify presence of Asian shrimp.

The survey was funded in part the Massachusetts Office of Coastal Zone Management, as well as by the New England Regional Sea Grant Consortium, a collaboration among Sea Grant programs in Rhode Island, Maine, New Hampshire, New York, Connecticut, and at the Woods Hole Oceanographic Institute and the Massachusetts Institute of Technology.  

“The consortium was eager to fund this project because it is clear we are seeing significant changes in our coastal ecosystem from from both climate change and invasive species,” said Rhode Island Sea Grant Director Dennis Nixon. “Professor Carlton has the background and experience to help us understand what is going on in this rapidly changing area. His survey might help us pinpoint areas for further, more detailed, research projects.”

Carlton’s work, spanning from the Pacific tsunami debris to his focus on non-native species here in the northeastern Atlantic, is a testament to the fact that the study of marine invasives has global implications. Understanding the often unintended dispersal of plants and animals across the world is a factor that will remain critical to the future health of coastal waters everywhere.

Evan Ridley and Meredith Haas | Rhode Island Sea Grant Science Communications