KEALIA — Marine debris on the coastlines of Hawaii is predominately plastic, according to an aerial survey of the eight main Hawaiian Islands.
Where it’s coming from is another question.
The study didn’t examine the source of the rubbish, but officials say most of it isn’t leftover from Japan’s 2011 tsunami. Local beach cleaners, however, say they’re finding some questionable things washed up on Kauai’s shores.
According to a news release from the Department of Land and Natural Resources, which commissioned the survey in partnership with North Pacific Marine Science Organization, the surveys were conducted between August and November.
On Kauai, the imagery analysis identified 2,878 pieces of marine debris. Nearly half of it was plastic, and most of the debris was concentrated on the eastern shores of the island.
The study found that 38 percent of the total marine debris that landed on Niihau was “likely due to its position in the island chain and the particular ocean currents surrounding it.” All the other islands had about 14 percent or less of the debris and Oahu had only about 5 percent of the debris — the least amount on all of the islands.
“This survey found a very limited amount of debris associated with the Japan tsunami,” said Suzanne Case, DLNR chairwoman in the release. “Most of what was mapped was common, everyday items that someone haphazardly tossed onto the ground, or directly into the water.”
On Saturday, Surfrider’s Net Patrol picked up nearly 1,300 pounds of trash and marine debris from Kealia Beach. Barbara Wiedner, vice chairwoman of Surfrider Kauai, said about 80 percent of it was marine debris.
“The majority (of the debris) wasn’t land based, meaning people weren’t dumping their things onto the coastline,” Wiedner said. “It was marine-based. The ocean was bringing it in by some different method.”
Wiedner said in 2015 alone, Surfrider Kauai and the organization’s volunteers removed more than 37,000 pounds of marine debris and trash from Kauai’s coastlines.
Wiedner said she’s seen an uptick in plastic on the island since the disaster.
“Now we’re seeing a lot of propane tanks in various sizes, large plastic palates that we didn’t see before, and tires that appear to be new, but covered in green algae,” Wiedner said.
In order to trace a piece of plastic back to the Japan tsunami, however, Wiedner said there needs to be a hard connection and that’s sometimes difficult to establish.
“So we need, for example, writing on a boat that we could trace back and then someone who says, yes, we lost that in the tsunami,” Wiedner said.
Robert Zelkovsky, also with Surfrider Kauai, said he’s seen several pieces of marine debris during cleanups over the past few years that have lettering from the Asian continent, but he can’t say for sure those pieces are from Japan.
“I don’t know if the language was Japanese, or Chinese, or Korean, but I have seen it here,” Zelkovsky said. “But also, when plastic has been in the ocean for four or five years, it starts breaking down so I don’t think where it came from can be identified.”
Zelkovsky said he thinks much of the marine debris comes from the Pacific Gyre Patch, also known as the Pacific Trash Vortex, which is a collection of marine debris in the North Pacific Ocean. Trash in the vortex collects in two distinct locations due to current activity — one near Japan and the other near California — with a smattering of trash in between.
Debris from the 2011 magnitude-9.0 earthquake off the coast of Northern Japan that killed more than 19,000 people and triggering multiple nuclear power plant meltdowns, has been found all across the Pacific, including Hawaii.
The Marine debris survey was paid for by the Ministry of Environment of Japan using the Japan Tsunami Gift Fund.
Jessica Else, environmental reporter, can be reached at 245-0452 or firstname.lastname@example.org.