A research team led by NOAA's Monterey Bay National Marine Sanctuary recently went in search of ghosts in the waters off Monterey.
They found them — or at least their gear.
Fishing lines, nets or traps lost or abandoned by fishermen can still snare animals, an occurrence known as ghost fishing.
Because the gear continues to work after the fishermen are long gone, marine animals can get caught or trapped in areas specifically set aside for their protection.
"Most of the gear we found was in marine protected areas," said Karen Grimmer, deputy superintendent of the sanctuary.
Although they find gear inside and outside of marine protected areas, the kinds of gear they find tend to differ with location.
Grimmer said gear inside marine protected areas tends to be older, left before the areas were designated as protected. Newer abandoned gear tends to be found outside marine protected areas.
The newer gear is especially worrisome, she said, because it is more resilient than older gear.
Lost and abandoned fishing gear can float in the ocean for years. Lines and cables can drag along the bottom, gouging the sea floor and ripping up animals, while floating nets can entangle and drown marine mammals. Abandoned gear poses a danger to humans by creating underwater hazards for swimmers and divers.
Local dive shop manager Keith McNutt said the most common piece of equipment he comes across is broken fishing line.
"You learn to look for it and avoid it," he said, but most divers carry a knife or scissors to cut themselves free if they get snagged.
Jim Barry, senior scientist at the Monterey Bay Aquarium Research Institute, said he has been on research cruises where the tether connecting a remotely operated vehicle to the boat became entangled in abandoned fishing gear at the edge of Monterey Canyon.
Although debris on the seafloor is not a good thing, Barry said, there are communities of invertebrates that can settle on abandoned equipment, creating a collection of life in otherwise sparse areas of the ocean.
Though the urge to remove all the lost fishing gear is understandable, Grimmer said, one of the many decisions scientists make is whether to remove lost gear that has a thriving marine community on it.
"If the gear is lying flat against the bottom with a significant number of marine invertebrates growing on it, it becomes a low-priority removal," she said.
Scuba divers can retrieve lost fishing gear in water up to 100 feet deep, while techniques such as using underwater robots are needed in deeper water, according to a report by The SeaDoc Society, a program of the Wildlife Health Center at the UC Davis School of Veterinary Medicine.
Grimmer said the recent 14-day research cruise, funded by the Monterey Bay National Marine Sanctuary and a state grant to the UC Davis SeaDoc Society, tested the best ways of removing lost gear from water deeper than 100 feet and used a remotely operated vehicle to look for lost and abandoned fishing gear.
Her team removed 400 feet of rockfish gill nets, three crab pots, one prawn trap and 600 pounds of lead clump weights used to ballast underwater robots.
The research team scouted a new protected area in Monterey Bay, the Portuguese Ledge State Marine Conservation Area, which contained an abandoned fishing net, complete with weights and doors, that they hope to retrieve next year.
Grimmer said it would be difficult because "we're going to have to figure out how to cut through steel cables," but the team hopes to continue the work in the future, depending on funding.
Grimmer is pleased with this kind of work, not only because it helps restore a protected area of the ocean, but because she and her staff can work with other agencies such as the California Department of Fish and Game, CSU Monterey Bay and programs such as the Marine Advanced Technology Education Center.
The research cruise is part of a "collaborative effort that enhances inter-agency communication and coordination," she said.
The Monterey Bay National Marine Sanctuary will post the locations of some abandoned fishing gear the team discovered — but wasn't able to remove — on its website so fishermen can avoid getting their gear tangled
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