An estimated 40 tons of marine debris wash up on Hawaiian reefs and beaches each year, and while cleanup efforts are cutting into the accumulated tangles of nets, ropes, plastic bottles, medical waste and other trash, the stuff keeps rolling in with the surf.

But several new programs are being launched to get a better understanding of the problem and to better harness the resources that can address it.

Goals include intercepting debris while it's still at sea, determining the economic impact of the debris on shipping and spreading the word about the threat from the rubbish.

There is no question that there is a lot of the stuff.

Debris collected in the Northwestern Hawaiian Islands increased from 4.9 tons in 1996 to 125 tons last year. And during last year's "Get the Drift and Bag It" debris collection project in the main Hawaiian Islands, nearly 2,500 volunteers collected more than 134,000 pieces of debris from beaches and nearshore reefs. This year's "Get the Drift" event was in September, and the results are still being tallied.

Vast amounts of the debris come from commercial fishing operations — largely from seafloor trawling — but a fair amount washes into the nearshore waters from land. It is unsightly and destructive. Drifting "ghost nets" catch and kill marine life, and tangles of heavy trawling gear wash through lagoons and rip up great swaths of coral reef with each new storm.

Multi-agency teams led by the National Oceanic and Atmospheric Administration's Fisheries Service have hauled nearly 500 tons of debris off the beaches and reefs of the Northwestern Hawaiian Islands since 1996, with a peak of 125 tons in 2004.

This year, that effort involved the loss of a ship, the 145-foot Casitas, which went aground July 2 on the northern reef of Pearl and Hermes Atoll. The crew got off safely and the Casitas was pulled off the reef, but was deemed too badly damaged to salvage. It was scuttled with 15 tons of already-collected nets and rope sealed aboard.

"Certainly, in the Northwestern Hawaiian Islands, we're catching up in a significant way," said Rusty Brainard, chief of the Coral Reef Ecosystem Division at the NOAA office in Honolulu. "We're collecting more than continues to (build up). But we estimate it is accumulating at 40 tons a year. The moment we stop, we start falling behind."

RUBBISH MIGRATES

The buildup moves with the currents. In most years, the largest amounts of debris hit the northernmost islands of the archipelago. In El Ni–o years, the currents appear to move south, taking the debris along to beaches in the main Hawaiian Islands.

Marine scientists have long known there are zones in the Pacific where large collections of net, rope and other material collect, serving as reservoirs of debris until storms or changing weather conditions drive them into the currents that lead to the Hawaiian Islands.

The High Seas Debris Detection and Tracking in the North Pacific program has set buoys in the collection zones and tracks them by satellite to learn more about these regions. Much of the floating debris is netting referred to as "ghost nets" — abandoned or lost fishing gear. One result of the research is that ghost nets can be intercepted at sea and hauled out of the water before they entangle corals on reefs and impact shorelines.

Researchers are trying to identify the sources of debris, but much is still unknown, including whether fishing fleets are deliberately dumping their worn-out gear or whether it's simply getting away from them.

"We really don't have any good numbers on how much is being purposely discarded and how much is being lost," Brainard said.

HAZARD FOR BOATERS

Besides the impacts on reefs and shores, there are the costs of having the debris in the ocean — and that's another unknown. Hawai'i anglers are familiar with having to dive under their boats to cut propellers free from nets. Last year, when the voyaging canoe Hokule'a was sailing through the Northwestern Hawaiian Islands, the crew of its escort boat had to make a dangerous midnight dive to cut snagged debris from the propeller.

The costs also are economic.

Researcher Chris Woolaway of the University of Hawai'i's Sea Grant Marine Advisory Program is launching a program with Coastal Zone Management Program funding to study issues such as the value of lost time and damaged equipment from propeller entanglements.

The marine debris control effort in Hawai'i also has a new voice in Carey Morishige, who was hired in September with NOAA funding as the marine debris outreach coordinator with the Sea Grant program. She previously worked in the state Department of Land and Natural Resources' coral reef program and as head of the Sierra Club's Blue Water Campaign.

"We live in a state where we are known for our marine environment, and it affects the beauty of the island," Morishige said.

Her goal, she said, is to increase awareness and organize community resources. A zoologist, she has seen the impact of coils of rope and net that entangle whales and seals and trap turtles, and the threat to sea birds and other species if they eat bits of plastic that may resemble food.

Morishige said the combination of new and old programs and technologies should put a dent in the problem.

"We all share a common goal to keep Hawai'i's environment clean and healthy," she said.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.