Posted on: Tuesday, June 1, 2004
Marine debris threatening wildlife in Northwestern Islands
By Jan TenBruggencate
Advertiser Science Writer
AT SEA, south of Gardner Pinnacles — Marine biologist Randy Kosaki spotted a large glass fishing float drifting by Hokule'a about 8:30 a.m. yesterday, just the latest of a string of sightings of marine debris on the ocean's surface.
The canoe radioed the ball's position to escort vessel Kama Hele, which normally remains a half-mile or more behind the canoe. Kama Hele's crew snagged the green glass ball, which appeared to be about 14 inches in diameter. The escort boat pulled alongside Hokule'a briefly to allow it to be photographed.
Marine debris is a serious problem for the wildlife of the Northwestern Hawaiian Islands. A consortium of government agencies and private concerns is involved in the removal and disposal of the stuff from the islands. Among them are the U.S. Fish and Wildlife Service, Coast Guard, Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve, University of Hawai'i, agencies of the city and state governments, SeaGrant Marine Extension Service, Hawai'i Metals Recycling, HPOWER, Honolulu Disposal, the Ocean Conservancy and the Coastal Zone Management Program.
The program started with pilot projects from 1996 to 2000, with most of the annual summer collection projects taking place at French Frigate Shoals. A more thorough debris removal project during the past three years has emphasized the more northern atolls of the chain, using professional and volunteer help and divers.
"Pearl and Hermes Atoll has the mother lode of the debris," said Rusty Brainard, chief of the Coral Reef Ecosystem Division of NOAA Fisheries.
"It's an extremely large atoll. The stuff comes over the barrier reef, and then, as big swells come through, it gets tangled and breaks free, gets tangled again and breaks free."
Each time, it breaks off coral and algae, which then increases damage as it rumbles across the atoll.
The 2001 haul was 69 tons. In 2002, it was 101 tons and last year 122 tons. This year, teams will work at Maro Reef where they expect a somewhat smaller haul.
"Maro has no barrier reef, so the stuff is more likely to wash through eventually," Brainard said.
Most of the debris appears to be from oceanic fisheries operations — chunks of gill and seine net, stretches of cargo net, pieces of trawl net, twisted hunks of line, sometimes with buoys attached.
These are the kinds of things that are the greatest risk to big animals, like seals, turtles and fish that can get caught in lost or abandoned "ghost" nets. Even seabirds get entangled when they land on or dive into floating nets.
"From 1982 to 2003 — 22 years — we have 238 documented entanglements of Hawaiian monk seals" or about 11 a year, said John Henderson, a NOAA Fisheries biologist. Most are pups. And no one knows how many animals die from entanglements.
Small bits of plastic are another threat, since feeding seabirds will often eat them, perhaps mistaking them for small edible marine life. While adult birds have the ability to regurgitate the stuff, some chicks die with their bellies full of plastic.
