Fishing 'ghost nets' are destroying Hawaii's sea life. Scientists are trying to pinpoint where they come from

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Jennifer Lynch is something of an ocean detective.

The Hawaii research biologist is supervising a massive study in which scientists are sorting through 21 tonnes of garbage-laden fishing nets that have washed up on Hawaii's shores. 

By performing detailed forensic work, they hope to pinpoint exactly which countries, fisheries and manufacturers are responsible for the mess.

"There are beautiful stretches of sandy or rocky shoreline with turquoise water, but at the high tideline, we see a piled-up line of plastic debris that is unmistakable and washing in from distant locations," Lynch, co-director of Hawaii Pacific University's Center for Marine Debris Research, told As It Happens host Carol Off. 

That debris, she says, is often ensnared in huge masses of what's known as "ghost nets." These are discarded fishing nets that often drift into the Great Pacific Garbage Patch north of the Hawaiian islands, then drag trash to its otherwise pristine eastern beaches.

"The islands act as a strainer, just straining that out of the ocean, and it piles up on our windward shores," Lynch said.

'A path of destruction'

The nets also wreak havoc on Hawaii's marine life while adrift, she said. 

They continue to ensnare fish long after they've been abandoned — something called "ghost fishing," hence their ominous nickname. They also kill seabirds, turtles and Hawaii's endangered monk seals. 

"As they near the shoreline, they begin to snag on our coral reefs," Lynch added.

"When a wave comes, then a very large mass of plastic gets pulled away from that snagged reef and it fragments and topples over corals. Sometimes we say bulldozed, because it literally leaves a path of destruction on its way up into the shallow areas. And then once it settles in a very shallow area on the coral, it will smother the coral that is sitting over the top of the earth."

Experts believe many nets are lost accidentally, but boats occasionally ditch nets to avoid prosecution when fishing illegally. Other fishermen cut away portions of damaged nets instead of returning them to shore.

Lynch and her team hope to trace the ghost nets back to their sources. 

The first step is disentangling them, documenting their dimensions, and seeing how the rope is stitched and where it attaches to fishing gear. 

Then samples will be sent to labs for a chemical analysis to identify their polymers. Different types of fisheries use different polymers, Lynch said, so this will help them narrow the search.

"We're also hoping that the chemical composition of the nets and the ropes will help us also identify the manufacturer or the country of manufacture," she said.

Over the last year, the researchers have found debris from all corners of the Pacific, including Asian countries and the U.S. West Coast. But the study is still in the research stages, and the scientists hope to have some solid findings for peer review later this year.

Mike Conroy, president of West Coast Fisheries Consultants, acknowledged that ghost gear is a problem. But he told The Associated Press he suspects local fisheries won't be identified as a major culprit. 

"These types of research activities will point the finger in the right direction," he said. "I think what you'll see is that West Coast fisheries probably aren't contributing much."

Much of the ghost net problem lies with less developed nations that have few fishing regulations and sometimes buy or manufacture low-quality nets, says Brian Fujimoto, a career fisherman who now works for a net manufacturer in Washington state.

"Their products tend to be weaker," Fujimoto, a sales executive for NET Systems Inc., told The Associated Press. "And if you look at the poly netting and ropes that you're finding, they're all very inexpensive stuff."

Lynch says the team isn't interested in pointing fingers so much as finding solutions.

"Our next steps, after we determine the origin of fisheries or gear manufacturers, is to engage with them, communicate with them, share our understanding of what their gear is doing here in Hawaii. And we hope for collaboration and working together to find preventative measures," she said.

"We're going to do our part as the scientists to put the data out there, and then allow the conversation to happen. We want to be there at the beginning of the conversation, and then the rest of the conversation can happen with policymakers, with fisheries organizations, with country-level governments. But it is going to be very challenging."

Written by Sheena Goodyear with files from The Associated Press. Interview with Jennifer Lynch produced by Jeanne Armstrong.