Jellyfish, crabs, sponges, mollusks and more — nearly 70 species in all — have hitched a ride on marine debris to Hawaii from Japan since the March 2011 tsunami there, according to the lead author of a new study published in Science Magazine.
Jim Carlton, a marine sciences professor at Williams College in Massachusetts, said the finding is a “game-changer” that presents serious challenges to government officials who must protect aquatic resources that the state’s tourism-driven economy depends on — not to mention the overall health of fragile island ecosystems.
Debris from the Japan tsunami has also been washing ashore along the West Coast of North America. Over the past six years, scientists have confirmed that almost 300 species of ocean critters survived the roughly 8,000-mile journey.
A polychaete, or bristle worm, hitched a ride to Hawaii on an adrift boat from Japan after the March 2011 tsunami.
Courtesy: Dan Lager
But what really stood out to Carlton and officials in the Hawaii Department of Land and Natural Resources was the reason many of these non-native animals are able to make such a trek.
Plastic does not break down in the ocean like wood and other biodegradable materials do. That lets barnacles, sea anemones, jellyfish and other animals “raft” on fishing buoys, floats and a host of other types of debris for years until they reach land.
And while the tsunami caused an influx of debris that also included boats, refrigerators and metal tanks, scientists are concerned that even small storms can and will bring wildlife from afar to the shores of places that have never seen such species.
“We’re entering a world now in the early 21st century where there’s this unexpected juxtaposition of having loaded coastlines with a vast amount of infrastructure that simply was not there 50 years ago,” Carlton said, noting Waikiki as a prime example.
What’s less clear is what effect these newly introduced species will have in Hawaii and elsewhere.
“It’s what we call ecological roulette,” Carlton said. “It’s a gamble — a gamble that we’d rather not take.”
This chart shows marine debris from the Japan tsunami in March 2011 and where it landed in Hawaii.
Bruce Anderson, who heads the DLNR Division of Aquatic Resources, said the new study — the first of its kind in marine science — brings a heightened awareness to the hidden hazards of marine debris.
“Marine debris is going to be an increasing risk as more and more of it occurs,” he said. “It hasn’t been given the attention it deserves.”
DLNR, which receives less than 1 percent of the state’s overall budget, has limited resources to deal with the problem, which Anderson views as environmental as much as economical.
“Given our reliance on the visitor industry, it’s embarrassing to go to some of our beaches and see all that debris,” he said, adding that items have washed up at popular parks as well as isolated valleys that are difficult to access.
The first verified marine debris from the March 2011 tsunami in Japan to reach Hawaii showed up at Oahu’s Makai Pier on Sept. 18, 2012.
Courtesy: Brian Neilson/DLNR
Community groups and nonprofits have been left to do the bulk of the work removing debris.
“I don’t think the state should be relying on volunteers to clean up beaches,” Anderson said. “But we really don’t have anyone at this point at the state level to do the coordination that’s necessary.”
He said he hopes the Legislature will take up the issue during its next session, which starts in January.
One key state official is on the case though. Brian Neilson, DLNR’s aquatic invasive species coordinator, worked with Carlton on the study.
He provided a steady stream of data beginning with the first verified Japanese tsunami item that arrived in Hawaii — a plastic container covered in barnacles at Makai Pier on the east side of Oahu on Sept. 18, 2012.
Neilson said he has an eight-person team based on Oahu that mostly works on planting sea urchins to eat an invasive algae that’s been threatening coral colonies in Kaneohe Bay. But they have also tried to respond to every report of possible Japanese tsunami debris.
For the neighbor islands, he said Surfrider Foundation, the Pacific Whale Foundation and the Hawaii Wildlife Fund, among others, have been critical supporters.
The items are logged into a database so the state can monitor areas that were exposed to non-native species and ensure they have not started establishing there, Neilson said.
There are already 400 different established aquatic nonnative species in Hawaii, he said.
“We’re kind of just in triage mode in terms of what we focus our management efforts on,” Neilson said.
DLNR’s aquatic invasive species team collects samples from a Japanese boat that washed ashore at Kailua Beach after the 2011 tsunami.
DLNR and members of the public were “superb” in keeping watch and responding to the debris that has come ashore, Carlton said. He added that it’s important that every item, whether it’s a buoy or a boat, is pulled out of the water and disposed of quickly and properly in a landfill so the non-native species don’t have a chance to settle in their new home.
“It’s really heartwarming and encouraging that a lot of folks are out there watching the shore and care,” he said.
Carlton expects to see an influx of non-native species rafting over from foreign lands as cities grow bigger, plastic use increases and storms become more severe due to climate change.
“It is we the public who are generating a lot of this plastic debris that’s ending up in the ocean. Preventing that is huge,” he said, noting the impact on ecosystems, the recreational value of coastal places and the amount of public money spent combatting invasive species.
Neilson noted the “piles of garbage everywhere” under the H-1 freeway in Kalihi as well as other places around the state.
“All that stuff is going to end up in the water in a big flood event,” he said. “We could all take some responsibility to keep this stuff out of the ocean.”
Of the hundreds of items that washed ashore in Hawaii from the Japan tsunami, Carlton said the good news is that nothing was radioactive. That had been a concern given the nuclear power plants in Japan that were destroyed in the earthquake that set off the tsunami.
This map shows where marine debris from Japan washed ashore in Hawaii after the 2011 tsunami.
Stay Up To Date On The Coronavirus And Other Hawaii Issues