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The Honolulu Advertiser
Posted on: Wednesday, October 31, 2001

Mystery of plastic tubes solved

By Jan TenBruggencate
Advertiser Science Writer

Those mysterious plastic tubes that wash up on Hawaiian beaches are a mystery no more.

Thousands of slender tubes have washed up on Hawai'i beaches. Many people were baffled as to their origin and purpose.

Jan TenBruggencate • The Honolulu Advertiser

They are spacers used in Japan's coastal oyster fisheries, which Japanese marine debris experts say escape when typhoons break up the bamboo rafts that suspend lines of farmed oysters.

The Advertiser and the National Marine Fisheries Service received dozens of calls yesterday after publication of a photograph and description of the plastic tubes, whose origin has baffled researchers in the Islands.

"The response was tremendous. I've never seen such a response to an article," said National Marine Fisheries Service biologist John Naughton. Some responses were reasonable, but some were strange, including one suggestion that the plastic cylinders were delivered by aliens.

The plastic tubes of various lengths come in black, gray, blue and green. They are found in large numbers in the annual Hawai'i Get the Drift and Bag It beach cleanups. Researchers say they are also common along the Northwestern Hawaiian Islands beaches.

They can be dangerous to marine life, as are many of the other pieces of marine debris that drift on the ocean currents.

University of Hawai'i Sea Grant extension agent Chris Woolaway said an Alaskan researcher reported finding dead albatrosses with the plastic tubes in their guts.

John Naughton, a marine biologist with the National Marine Fisheries Service, said that when the plastic breaks up into smaller pieces, it is likely eaten by other seabirds as well, and possibly by turtles and other forms of marine life.

But nobody in the Islands knew where they came from until Mark Heckman of Waikiki Aquarium a few weeks ago found a Japanese Web site that identified them. Heckman had sent a message about the Web site to the University of Hawaii Sea Grant program, and Sea Grant forwarded that message to the National Marine Fisheries Service, as a result of the Advertiser story.

"If I'd searched for them just a year ago, I wouldn't have found them. The environmental community in Japan has progressed to the point where they're doing beach cleanups, and one community put what they found on a Web site," Heckman said.

The shoreline cleanup program for the Kansai and Chugoku regions of Japan, which include Kyoto, Osaka and Kobe, put some of its results on the Internet, and identified a number of the odd items of marine debris.

The plastic tubes, they report, are used as spacers on strings of oysters suspended under huge bamboo rafts in the coastal waters of Japan. Sometimes, typhoons tear up the rafts, and release the plastic tubes.

They only started showing up on beaches after the fishery switched from PVC tubes, which sink, to polyethylene, which floats, the Web site says.

While many of the tubes wash up on Japan beaches, others are swept up in the northbound Kurushio current, which flows along Japan's Pacific coast and then sweeps eastward along the Aleutians, south down the coast of North America and westward past Hawai'i. It is the same North Pacific current system that carries glass fishing floats from Asian and Alaskan fisheries to Hawaiian beaches.

Naughton said Japan may not be the only — or even the primary — source of the tubes, because there may be similar oyster fisheries in other nations around the Pacific.

Charles Helsley, the former head of Hawai'i Sea Grant and now a researcher emeritus with the program, said he will take a collection of the tubes to a December 2001 conference in Japan, to confirm that they are from the oyster fishery and to discuss ways of reducing the release of the plastic tubes into the ocean.

You can reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808)245-3074.

 •  On the Web

An image of the plastic tubes washed up on a Japan beach is found at www.page.sannet.ne.jp/m_terui/special_e.html#kaigai Drawings showing how the tubes are used in oyster farming are found at www.page.sannet.ne.jp/m_terui/kakimap_e.html