Marine Debris Research and Removal in the Northwestern Hawaiian Islands

In the Northwestern Hawaiian Islands, we most often find derelict fishing nets, floats, foam buoys, plastic fragments, plastic bottles, bottle caps, cigarette lighters, shoes, and toothbrushes. Marine debris is any persistent solid material that is manufactured or processed and disposed of or abandoned into the ocean, rivers, or lakes. Marine debris is a threat to wildlife and habitat, navigation safety, the economy, and human safety and health. Today, almost every waterway and shoreline is impacted by marine debris, even in areas as remote as the protected Northwestern Hawaiian Islands.

The North Pacific Subtropical Gyre is a clockwise pattern of the prevailing ocean currents (North Pacific, California, North Equatorial, and Kuroshio currents) that circulate around the Hawaiian Archipelago.

Where is the debris coming from?

The Hawaiian Islands are the most remote island chain in the world, yet beaches are littered with marine debris. The waters surrounding the unpopulated Northwestern Hawaiian Islands are protected as part of the Papahānaumokuāea Marine National Monument, a World Heritage site and the largest fully-protected conservation area. The convergence of ocean currents (gyre) in the region carries lost and abandoned fishing nets and gear from all over the Pacific Ocean, primarily large trawl and drift nets, to the Northwestern Hawaiian Islands. The small islands and atolls act like a filter or comb in the center of the gyre, catching marine debris from the currents, and tangling nets on shallow coral reefs.

What are the impacts of marine debris?

As debris rolls across shoreline habitats and reefs, derelict fishing nets can entangle wildlife and damage corals. Derelict fishing gear is especially damaging to fragile coral reefs—some of the most biologically diverse and economically valuable ecosystems on earth¹. Derelict fishing nets wear down and break corals or can even grow into the reef structure, smothering living coral.

A Hawaiian monk seal rests atop a 11.5-ton “monster” derelict fishing net conglomerate that the team located and successfully removed in 2015. (Photo: NOAA Fisheries)

In addition to damaging corals, derelict fish gear poses a serious choking and entanglement hazard to many threatened or endangered marine species and seabirds in the Northwestern Hawaiian Islands—including the Hawaiian monk seal, green sea turtle, humpback whale, and Laysan albatross. If animals get entangled in nets or swallow plastic debris, they can suffocate, starve, or drown. Derelict fishing nets and gear can also constrict an entangled animal’s movement, can exhaust or injure the animal. Other possible impacts of marine debris include the introduction of invasive species, hazards to boat navigation, and the degradation of beautiful coastlines.

Our marine debris missions

Our team focuses on surveying and cleaning up marine debris and derelict fishing gear in the Northwestern Hawaiian Islands, an ecologically and culturally significant area. The reefs constitute approximately 70% of all tropical, shallow-water coral reef habitat in the entire United States. These coral reefs are home to more than 7,000 marine species—one quarter of these species are endemic or found only in Hawai‘i.

We collect nets and debris that damages coral reefs and could entangle or injure wildlife. In addition to fishing nets, buoys, and floats, there are also consumer plastics on the islands, including bottles, bottle caps, cigarette lighters, toys, and toothbrushes. The team regularly surveys and removes debris from the following islands, atolls, and reefs in the Northwestern Hawaiian Islands:  Kure Atoll, Midway Atoll, Pearl and Hermes Atoll, Lisianski Island, Laysan Island, Maro Reef, and French Frigate Shoals.

Since 1996, the team has removed 848 metric tons (more than 900 tons or 1.9 million pounds) of derelict fishing gear. Derelict fishing gear continues to accumulate at an estimated rate of 52 metric tons per year in the Northwestern Hawaiian Islands². Follow our mission to the Northwestern Hawaiian Islands in 2018 on the Story Map.

The team hauls away derelict fishing gear from reefs and shorelines, then transfers the piles from small boats onto a large NOAA ship. (Photo: NOAA Fisheries/Ryan Tabata)

What happens to the debris?

When we complete a marine debris removal operation, we bring the nets and plastics back to Honolulu aboard the NOAA ship or charter vessel. A key partner in the recycling process, Schnitzer Steel (a metal recycling company) chops the fishing nets into small pieces. The net pieces are then transported to the City and County of Honolulu’s H-Power Plant (a Convanta Energy Corporation facility), where they are safely incinerated to produce electricity for the island of Oahu.

The team brings collected fishing nets back to Honolulu to recycle into energy. (Photo: NOAA Fisheries/David Slater)

What can you do to help?

• Refuse, Reduce, Reuse, and Recycle!
• Recycle used fishing nets and line.
• Participate in a local beach cleanup.

The Honolulu Derelict Net Recycling Program, funded by NOAA, is an exemplary project that brings together industry, fishermen, local, state, and Federal partners to proactively remove and recycle derelict nets. Derelict fishing gear retrieved by volunteer fishermen are deposited into a dedicated collection bin located behind United Fishing Agency and Pacific Ocean Producers, at Pier 38, Honolulu Harbor. The nets and gear are ultimately converted to electricity through the Hawai‘i Nets-to-Energy Program.

For more information

• Removal and Research: The Marine Debris Team Strikes Again
• Blog Series: Northwestern Hawaiian Islands Marine Debris Mission 2018
• Story Map
• Protecting Paradise: Marine Debris Team Does the Heavy Lifting

• Video: Spotlighting the Threat Marine Debris Poses to Wildlife in Papahānaumokuākea

Partners

NOAA Fisheries marine debris project in the Pacific Islands region is supported by NOAA (Pacific Islands Fisheries Science Center, Pacific Islands Regional Office, Marine Debris Program, and the Damage Assessment Remediation and Restoration Program) in partnership with the University of Hawaii's Joint Institute for Marine and Atmospheric Research, National Fish and Wildlife Foundation, U.S. Fish and Wildlife Service, Midway Atoll National Wildlife Refuge, the State of Hawaii’s Department of Land and Natural Resources, and the Papahānaumokuākea Marine National Monument.

Contact

For more information about our marine debris project, or to inquire about education and outreach opportunities, please contact James Morioka.

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References

¹ From the book, Reefs at Risk: A Map-Based Indicator of Threats to the World’s Coral Reefs, by Burke, McManus, and Spalding, [World Resources Institute], 2007.

² Marine debris accumulation in the Northwestern Hawaiian Islands: An examination of rates and processes.