09:45 〜 10:00
[MIS02-04] Source identification of ALDFG from the international eel/hagfish fisheries of the North Pacific Ocean,
and measures to reduce its impact
キーワード：放棄、逸失、もしくは投棄 された漁具、海洋ゴミ、うなぎ漁業、北太平洋
The Hawaiian Islands, sitting in the middle of the North Pacific Ocean, sieve marine debris from ocean
currents and deposit it on windward shores. In 2024 Surfrider Kauai collected over 70 mt of debris. As
much as 90% of the mass of this debris is plastic ALDFG from international fishing fleets. While fishing
nets/ropes/lines make up the largest portion, followed by fishing bins and floats, the cylindrical tubes
and cone-shaped entrances to traps designed to catch eel-shaped marine animals (e.g., conger eels,
moray eels, hagfish) are abundant. A total of 21,504 pieces of eel traps were collected in Hawaii during
2021-2024. In 2024 an average sum of 687 pieces of eel traps were collected each month on the four
main islands.
Through collaboration with scientists in Taiwan, South Korea, and Japan we distinguished differences in
the morphology of the traps most commonly used by eel fishermen in each country. Studies of the
polymers of the eel traps were not useful, as they are made of varying compositions of recycled plastic
pellets. However, lettering embossed on the eel trap entrances designated the country and location of
manufacture. Branding on the tubes sometimes identified the port city, boat or fisherman, which
allowed the return of lost gear.
While some eel fishing gear is lost to sea-bottom entanglements, gear conflicts, extreme weather
events, or tsunamis, the majority appears to be discarded by large-scale commercial fishing boats laying
as many as 10,000 traps at a time. The most commonly found eel trap parts are of the type used by
South Korean and Chinese fishermen. Discarded gear, as it is made of polypropylene/polyethylene
mixtures, floats in the ocean causing damage to marine organisms due to ingestion or entanglement.
Lost eel traps remain on the bottom if they are weighted down and continue to capture, entangle and
kill both targeted and non-targeted species, and as this plastic degrades and disintegrates into
microplastics and nannoplastics, it continues to enter and poison marine food chains.
Efforts to reduce plastic ALDFG pollution include international, national and more local laws against
discarding materials, especially plastic, overboard; encouraging the return of damaged gear to port by
providing recycling facilities or buy-back programs; and inventing materials specifically designed to
biodegrade on the ocean bottom. This includes the development of both new polymers and the design
of new eel trap entrances to quickly break apart. An unintended character of biodegradable materials is
a density greater than that of seawater, meaning that they do not float, thus they do not contaminate
surface waters or float on ocean currents to the North Pacific Garbage Patch or the Hawaiian
archipelago. The South Korean government has developed such material and is promoting its use in fish
nets, traps and pots by Korean fishermen and internationally. Their biodegradable eel trap entrances
are being tested for durability by fishermen on the west coast of North America. U.S. scientists have
developed another non-toxic biodegradable polymer and are testing its rate of biodegradation.
Hopefully, worldwide efforts will rid the oceans of plastic ALDFG.
This international North Pacific Eel Trap Project was done in collaboration with Dr. Satoquo Seino, Hideo
Kinoshita (Kyushu University, Japan), Ai Iwamoto (Surfrider Foundation Japan), Eo Jin (University of
Korea, Seoul), Ning Yen, Chieh-shen Hu, Chi-hsuan Hsu (Indigo Waters Institute, Taiwan), Barbara
Weidner, Scott McCubbins, Cynthia Welti (Surfrider Foundation, Kauai), Megan Lamson (Hawaii Wildlife
Fund), Cheryl King (Hawaii Sharkastics), Dr. Jennifer Lynch, Dr. Sara-Jeanne Royer, Paige White (Hawaii
Pacific University), Dr. James Carlton (Williams College), Lauren Blickley, Hanna Lilley (Surfrider
Foundation).
currents and deposit it on windward shores. In 2024 Surfrider Kauai collected over 70 mt of debris. As
much as 90% of the mass of this debris is plastic ALDFG from international fishing fleets. While fishing
nets/ropes/lines make up the largest portion, followed by fishing bins and floats, the cylindrical tubes
and cone-shaped entrances to traps designed to catch eel-shaped marine animals (e.g., conger eels,
moray eels, hagfish) are abundant. A total of 21,504 pieces of eel traps were collected in Hawaii during
2021-2024. In 2024 an average sum of 687 pieces of eel traps were collected each month on the four
main islands.
Through collaboration with scientists in Taiwan, South Korea, and Japan we distinguished differences in
the morphology of the traps most commonly used by eel fishermen in each country. Studies of the
polymers of the eel traps were not useful, as they are made of varying compositions of recycled plastic
pellets. However, lettering embossed on the eel trap entrances designated the country and location of
manufacture. Branding on the tubes sometimes identified the port city, boat or fisherman, which
allowed the return of lost gear.
While some eel fishing gear is lost to sea-bottom entanglements, gear conflicts, extreme weather
events, or tsunamis, the majority appears to be discarded by large-scale commercial fishing boats laying
as many as 10,000 traps at a time. The most commonly found eel trap parts are of the type used by
South Korean and Chinese fishermen. Discarded gear, as it is made of polypropylene/polyethylene
mixtures, floats in the ocean causing damage to marine organisms due to ingestion or entanglement.
Lost eel traps remain on the bottom if they are weighted down and continue to capture, entangle and
kill both targeted and non-targeted species, and as this plastic degrades and disintegrates into
microplastics and nannoplastics, it continues to enter and poison marine food chains.
Efforts to reduce plastic ALDFG pollution include international, national and more local laws against
discarding materials, especially plastic, overboard; encouraging the return of damaged gear to port by
providing recycling facilities or buy-back programs; and inventing materials specifically designed to
biodegrade on the ocean bottom. This includes the development of both new polymers and the design
of new eel trap entrances to quickly break apart. An unintended character of biodegradable materials is
a density greater than that of seawater, meaning that they do not float, thus they do not contaminate
surface waters or float on ocean currents to the North Pacific Garbage Patch or the Hawaiian
archipelago. The South Korean government has developed such material and is promoting its use in fish
nets, traps and pots by Korean fishermen and internationally. Their biodegradable eel trap entrances
are being tested for durability by fishermen on the west coast of North America. U.S. scientists have
developed another non-toxic biodegradable polymer and are testing its rate of biodegradation.
Hopefully, worldwide efforts will rid the oceans of plastic ALDFG.
This international North Pacific Eel Trap Project was done in collaboration with Dr. Satoquo Seino, Hideo
Kinoshita (Kyushu University, Japan), Ai Iwamoto (Surfrider Foundation Japan), Eo Jin (University of
Korea, Seoul), Ning Yen, Chieh-shen Hu, Chi-hsuan Hsu (Indigo Waters Institute, Taiwan), Barbara
Weidner, Scott McCubbins, Cynthia Welti (Surfrider Foundation, Kauai), Megan Lamson (Hawaii Wildlife
Fund), Cheryl King (Hawaii Sharkastics), Dr. Jennifer Lynch, Dr. Sara-Jeanne Royer, Paige White (Hawaii
Pacific University), Dr. James Carlton (Williams College), Lauren Blickley, Hanna Lilley (Surfrider
Foundation).