2018 Marine Debris Removal and Assessment in the Northwestern Hawaiian Islands

The Papahānaumokuākea Marine National Monument includes all of the Northwestern Hawaiian Islands and encompasses 1,508,870 sq km (582,578 sq mi) of the Pacific Ocean.

Within the boundaries of the monument lie coral reefs, atolls, shoals, and seamounts, including 70 percent of all shallow-water coral reef habitats (shallower than 200 m) in the United States.

The monument was named a World Heritage site in 2010 by the 34th session of the World Heritage Committee in recognition of its cultural and natural values.

The extensive coral reefs found in the monument are home to more than 7,000 marine species, one-quarter of which are found only in the Hawaiian Archipelago.

Many of the islands and shallow-water environments in the monument are important habitats for rare species, such as the threatened green sea turtle and endangered Hawaiian monk seal.

The monument contains only 15 sq km of emergent land, but 14 million seabirds representing 22 species use this land as breeding and nesting grounds. Land areas provide a home for four species of birds found nowhere else in the world, including one of the world’s most endangered ducks—the Laysan duck. The monument is centrally located within the world’s largest ocean gyre, the North Pacific Gyre). This gyre is a system of clockwise rotating ocean currents between 8° N and 50° N latitude which extends across approximately 20 million sq km (7.7 million sq mi) of ocean.  

Marine debris (including plastics and derelict fishing gear) originating from across the North Pacific Rim is often entrained and then concentrated within this gyre. The Hawaiian Islands are located just south of the gyre’s convergence zone, resulting in the islands and atolls of the NWHI being particularly prone to marine debris accumulation. At least 52 metric tons (115,000 lb) of derelict fishing gear is estimated to accumulate on the shallow coral reefs of the monument each year.

Since 1996, the Pacific Islands Fisheries Science Center and partners have conducted ship-based, large-scale removal of derelict fishing gear and plastics from the reefs and shorelines of Papahānaumokuākea Marine National Monument in order to mitigate the entanglement and ingestion threats to protected wildlife as well as damage to coral reefs.

Morioka J, O'Brien K, Huntington B, Suka R, Acoba T. 2020. 2018 Marine Debris Removal and Assessment in the Northwestern Hawaiian Islands. Pacific Islands Fisheries Science Center, PIFSC Special Publication, SP-20-001, 8 p.  https://doi.org/10.25923/f19b-je14.