Sources of Marine Plastic Pollution

Community Contributed
Clare Gallagher, PhD Student, Environmental Studies

On a hot summer day in 2022, Jasmine Buerano found herself on a remote coastline of Molokai, hacking away at a 1,000-pound bluish-gray fishing net that smelled like seawater.

Buerano, the storytelling coordinator for the non-profit Sustainable Coastlines Hawaii (SCH), along with 15 other volunteers, couldn’t gawk for long. They were racing the tide.

They tackled the huge net in sections to put into “super sacks,” which would be scooped up by a helicopter the next day. But in addition to consolidating the net and other plastic trash, they had to move the sacks across rocky tidal pools, up a steep embankment, and above the high tide line so that the sacks wouldn’t be taken back out to sea later.

“I have this distinct memory of [Molokai volunteers] Todd, Cody and George, rolling this 200-pound bag full of debris over huge rocks that scattered across the shoreline. It was so gnarly,” Buerano said. “I was blown away. I’d seen photos and videos of ghost nets, but I’d never actually been immersed in the experience of seeing this discarding of convenience.”

In 2022, volunteers picked up 20,000 pounds of marine debris on Molokai shorelines. Last summer, volunteers cleaned up another 8,000 pounds, while grieving and supporting the Lahaina wildfire tragedy from afar. This coming summer, there will be another week of cleanups on Molokai. Residents can check SCH’s website for dates at sustainablecoastlineshawaii.org.

Discarded fishing gear, often called ghost gear, continues to kill other marine animals long after fishing vessels have lost contact with it. A 2022 Nature paper by oceanographer and plastic degradation scientist Dr. Sarah-Jeanne Royer from Hawaii Pacific University, and other scientists, reported that between 75 and 86 percent of the pieces floating in the Great Pacific Garbage Patch that are longer than five centimeters are ghost nets or parts of nets.

“This is huge,” Royer said of the finding.

Even more alarming, this is only the debris that floats. Scientists estimate that around 70 percent of all marine plastic debris eventually sinks. This means that most discarded purse seines, which are made with nylon and mostly fish schools of tuna, end up sinking.

And the debris from the Great Pacific Garbage Patch doesn’t necessarily stay there. More recently, Royer and other scientists published a paper in Marine Pollution Bulletin that reported and analyzed over 250 beached debris events on coastlines of Hawaii and Palmyra, a remote Pacific atoll, from 2009 to 2021, totaling over 33,000 pounds.

The majority of the debris? Industrial fishing nets, just like the one Buerano and crew removed.

The United Nations has recently continued negotiations on a treaty to end plastic pollution. The final treaty is likely to include a provision on fishing gear. But, whether it addresses the global problem of ghost gear remains to be seen.

For now, Buerano explained that SCH is always looking for more volunteers. While cleanups are not going to solve the problem, they build community and increase awareness.

“And someone always brings a speaker,” Buerano said.