Sea critters hitchhiked across the Pacific on tsunami debris This June 2012 photo provided by John W. Chapman shows Japanese sea stars (Asterias amurensis) on a Misawa, Japan fisheries dock which washed ashore near Newport, Ore. (John W. Chapman via AP)
Sea critters hitchhiked across the Pacific on tsunami debris

Nearly 300 species of fish, mussels and other sea critters hitchhiked across the Pacific Ocean. They traveled on debris from the 2011 Japanese tsunami and washed ashore alive in the United States. That's what researchers reported Thursday.

It is the largest and longest marine migration ever documented, according to outside experts and the researchers. The scientists and colleagues combed the beaches of Washington, Oregon, California and British Columbia. They also combed the beaches of Alaska and Hawaii. They tracked the species to their Japanese origins. Their arrival could be a problem if the critters take root because they could push out native species. That's what the study authors said in Thursday's journal Science.

"It's a bit of what we call ecological roulette," said lead author James Carlton. He's a marine sciences professor at Williams College in Williamstown, Massachusetts.

It will be years before scientists know if the 289 Japanese species thrive in their new home and crowd out natives. The researchers roughly estimated that a million creatures traveled 4,800 miles (7,725 kilometers) across the Pacific Ocean. 

Invasive species are a major problem worldwide. It’s when plants and animals thrive in areas where they don't naturally live. Marine invasions in the past have hurt native farmed shellfish. They also eroded the local ecosystem, caused economic losses and spread disease-carrying species. 

A magnitude 9 earthquake off the coast of Japan triggered a tsunami on March 11, 2011, sweeping boats, docks, buoys and other man-made materials into the Pacific. The debris drifted east with an armada of living creatures. Some gave birth to new generations while at sea.

"The diversity was somewhat jaw-dropping," Carlton said. "Mollusks, sea anemones, corals, crabs, just a wide variety of species, really a cross-section of Japanese fauna."

The researchers collected and analyzed the debris that reached the West Coast and Hawaii over the last five years, with new pieces arriving Wednesday in Washington. The debris flowed across the North Pacific current, as other objects do from time to time, before it moved north with the Alaska current or south with the California current. Most hit Oregon and Washington.

Last year, a small boat from Japan reached Oregon with 20 good-sized fish inside, a kind of yellowtail jack native to the western Pacific, Carlton said. Some of the fish are still alive in an Oregon aquarium. Earlier, an entire fishing ship - the Sai sho-Maru - arrived intact with five of the same 6-inch fish swimming around inside.

Co-author Gregory Ruiz, a Smithsonian marine ecologist, is especially interested in a Japanese parasite in the gills of mussels. Elsewhere in the world, these parasites have taken root and hurt oyster and mussel harvests and they hadn't been seen before on the West Coast.

The researchers note another huge factor in this flotilla: plastics.

Decades ago, most of the debris would have been wood and that would have degraded over the long ocean trip, but now most of the debris - buoys, boats, crates and pallets - are made of plastic and that survives, Carlton said. And so the hitchhikers survive, too.

"It was the plastic debris that allowed new species to survive far longer than we ever thought they would," Carlton said.

James Byers is a marine ecologist at the University of Georgia in Athens and wasn't part of the study. He praised the authors for their detective work and said in an email that the migration was an odd mix of a natural trigger and human aspects because of the plastics.

"The fact that communities of organisms survived out in the open ocean for long time periods (years in some cases) is amazing," he wrote.

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Why is this considered “hitchhiking?"
Write your answers in the comments section below

  • David M-del
    10/04/2017 - 06:13 p.m.

    There called hitched hikers because the tsunami dragged all of the sea critters away from their homes to the shore.

  • ChloeT-del
    10/04/2017 - 06:29 p.m.

    This is considered "hitchhiking" because the items from debris from the tsunamis pushed the sea critters across the Pacific Ocean. This is very dangerous and a serious issue because items or debris shouldn't be pushing and leading the critters anywhere. People should not litter and should think about sea critters and how litter and debris could endanger their lives.

  • SarahT-del
    10/04/2017 - 06:46 p.m.

    Thats so awesome that a disaster from 2011 becomes a find in science.
    The animals really did hitchhike. They took the debris and rode the current and they landed here.

  • PedroM-del1
    10/04/2017 - 06:46 p.m.

    This was very interesting about how it took so long just to get from one continent to the other. But PEOPLE need to help the ocean so no one will McDonald's or Kars for Kids on the beach cause no one wants that. No one. NO ONE. NO ONE I say!!!!!

  • DevanS-del
    10/04/2017 - 06:48 p.m.

    I find it very interesting that an abundance of new marine species have landed on the West Coast. Although it may cause disease, I think it's a good chance for scientists to study them. They can learn information about these new species of animals and potentially find something very useful.

  • PedroM-del1
    10/04/2017 - 06:52 p.m.

    Hitchhiking when lonely stranded people stand by a road in lonely area to get somewhere else. In this case lonely animals were swept away without asking.

  • EmilyN-del1
    10/04/2017 - 07:05 p.m.

    It is considered hitchhiking because the sea creatures grabbed on and rode on the debris. I think it is fascinating that fish can ride on plastic!

  • OlivierJ-del
    10/04/2017 - 07:27 p.m.

    It is very interesting how sea creatures can take advantage of other sea creatures. The debris from tsunamis is being carried by the ocean's wave. This is hitchhiking.

  • ReesePratt-del
    10/04/2017 - 07:30 p.m.

    It is considered hitchhiking because they do no work it is like they are getting a free ride

  • JasminderK-del
    10/04/2017 - 08:15 p.m.

    It is sad that all the species in the Japanese ocean had to move all the way over to our oceans, but it is surprising that plastic helped them survived.

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