By Jan TenBruggencate
Advertiser Columnist

Japanese fishery officials are working on changing the equipment used in oyster farming to minimize the release of plastic tubes that end up on Hawai'i beaches by the thousands.

The polyethylene tubes are hollow and a half-inch thick, in lengths from 1 or 2 inches to 8 or 9 inches.

Their origin was a mystery until last year, when Hawai'i officials discovered they are used in the Japanese coastal oyster fishery.

The tubes are used as separators between clusters of oysters growing on scallop shells, which are strung on cords under rafts. During storms, the rafts sometimes break loose, setting thousands of plastic tubes adrift on the North Pacific currents.

Once the tubes are adrift, seabirds can eat them. Dead albatross have been found with their bellies full of them.

Rick Steiner, a biologist and professor with the University of Alaska Marine Advisory Program, brought the issue to Japan fisheries officials and said the response has been positive.

Steiner said he met recently with officials of the Japan Fisheries Agency and the Japan Environmental Action Network. Japanese officials were impressed by photographs of marine debris on Hawaiian shores and of dead seabirds stuffed with plastics, he said.

"They began a research project to learn more about all of this," he said. "They queried all prefectures in Japan and found that some 24 prefectures do oyster farming, of which one uses largely bamboo pipes, thus not really a problem for us. Ten use the plastic pipes and one uses a rubber pipe. The other 12 prefectures use another method entirely: a twisted rope within which the scallop substrate shells are secured at fixed intervals, with no need for the plastic pipes."

Steiner said the Japanese government asked the largest oyster-farming prefecture, Hiroshima, to consider switching from plastic spacers to the twisted-rope method.

The oyster growers also are looking into methods to prevent rafts from breaking free in typhoons.

"All of these oyster growers now know of the problem and feel a sense of responsibility to help resolve the issue. They don't want to lose their gear, and now know that it is having broad impact across the Pacific," Steiner said.

The changes in the oyster fishery could stop the release of polyethylene tubes in the Pacific.

"This is a wonderful step toward resolving this issue," Steiner said. "Of course, this is just the tip of the proverbial iceberg when it comes to the marine debris problem, but it is a start."

Jan TenBruggencate is The Advertiser's Kaua'i bureau chief and its science and environment writer. Reach him at (808) 245-3074 or e-mail jant@honoluluadvertiser.com.