Combating Derelict Gear and Plastic Pollution in Aquaculture

Fishing for a Solution

ByDeesha Sharma, 2025 USC Sea Grant Intern April 30, 2025

According to the National Oceanic and Atmospheric Administration (NOAA), aquaculture refers to the practice of breeding, harvesting, and rearing fish, shellfish, algae, and other organisms in various water environments. These organisms are used for food, jewelry, medicine, and everyday products such as toothpaste and salad dressing.

For many decades, aquaculture has proven to be a vital social, cultural, and economic practice. In fact, a study from the United Nations stated that when aquaculture is done correctly, it can improve food security and nutrition while keeping waterways clean and boosting the economy through coastal and rural employment. However, if done incorrectly, it can pose significant environmental and economic problems within marine communities and ecosystems. One of the major concerns is derelict gear, also known as ghost gear, which presents serious threats to both the environment and the economy.

Derelict gear refers to lost or discarded fishing equipment that is no longer under the control of commercial or recreational fishers. This can include lines, nets, pots, traps, floats, and other equipment. Unfortunately, most modern fishing gear is made of synthetic, non-biodegradable materials, allowing it to persist in the ocean for long periods. Gear may be intentionally discarded in water bodies, or it may be lost when it gets cut or caught on other vessels, breaks away from overuse, or is displaced during storms and natural disasters.

An illustration detailing the impacts of derelict crab traps. A 2016 study suggested that removing just 10% of derelict crab and lobster traps worldwide could increase landings by 293,929 metric tons. (Credit: Virginia Institute of Marine Science)

Abandoned gear is particularly dangerous for marine life because it continues to capture and trap fish, sea turtles, seabirds, crustaceans, and even marine mammals—a phenomenon called ghost fishing. This occurs in a cascading fashion: smaller prey become trapped in the equipment, attracting larger predators that, in turn, also become ensnared. Additionally, derelict fishing gear can destroy coral and seagrass habitats as it drags across the seafloor.

Nets continue to catch fish and unintended bycatch, even after they are abandoned (Credit: NOAA Marine Debris Program)

Ghost gear also has the potential to wreak economic havoc on the fishing industry and coastal communities. First and foremost, it can cause boat collisions and damage vessels by getting caught in engines or propellers. It can also ruin functional fishing gear and compete with active fisheries and aquaculture farms by trapping economically important species.

Although it is difficult to determine the exact amount of derelict gear in the ocean today, a NOAA-funded study estimated that nearly 145,000 derelict crab pots are in the Chesapeake Bay, with the potential to kill about 3.3 million blue crabs annually. Additionally, this gear has made its way into some of the most remote and protected areas of the country, including the Papahānaumokuākea Marine National Monument—the largest fully protected marine conservation area on Earth. This monument is home to 23 endangered species and is completely uninhabited by humans; however, approximately 50 metric tons (approximately 10 fully loaded school buses) of marine debris, primarily derelict fishing gear, accumulate on its shores each year.

But do not fear—there is hope! Various local, state, and national governmental agencies, along with academic institutions, have dedicated grants and resources to the removal of derelict fishing gear in California and across the country. At the national level, NOAA’s Marine Debris Program is part of the Fishing for Energy partnership, alongside the National Fish and Wildlife Foundation, Covanta, and Schnitzer Steel Industries. Their goal is to provide fishers with a free avenue to dispose of old gear, which is then recycled and converted into energy.

Abandoned crab pots collected by the NOAA Marine Debris Program (Credit: NOAA Marine Debris Program)

A state-level initiative, “The California Lost Fishing Gear Recovery Project,” has removed more than 90,968 pounds (about 8 fully loaded school buses) of derelict gear from the coasts of Santa Barbara, Ventura, Los Angeles, Orange, and San Diego, as well as around the Channel Islands, in 2020 and 2021. The project, which is part of the Karen C. Drayer Wildlife Health Center at the UC Davis School of Veterinary Medicine, began in 2006 and has since removed thousands of nets, pots, and traps while releasing hundreds of live sharks, fish, and invertebrates (e.g., lobsters, crabs) back into the ocean. Over the course of just 133 days, the team retrieved 666 pieces of fishing gear and documented approximately 1,400 live animals and more than 7,900 carcasses trapped within them.

Another problem that must be addressed in aquaculture is the extensive use of plastics at every level of production, including tanks, nets, feed bags, liners, foam buoys and piping equipment. Plastic has become an attractive material in aquaculture due to its lightweight nature, durability, and low cost. However, the widespread use of this material in the ocean has led to the formation of “Aquaculture-Derived Microplastics” (AD-MPs). While land-based plastics remain the largest threats to marine ecosystems, aquaculture facilities contribute up to 10% of global marine plastics and more than 50% of the microplastics in areas surrounding aquaculture facilities. These microplastics come from the gradual degradation of this equipment, which breaks down over time due to plunged exposure to UV radiation and wave action.

Microplastic on a beach (Credit: NOAA National Ocean Service)

In response to these concerns, efforts to move away from plastics in aquaculture are being pursued. For instance, MycoBuoys is a start-up that has developed an alternative to foam buoys using mycelium, a type of fungus capable of making water-repellant proteins. These bio-buoys have already been implemented in eleven shellfish and seaweed aquafarms in the northeastern United States, and the company is now expanding its product line to create mycelium storage coolers, rafts, and bobbers. The scientific community continues to explore solutions to mitigate aquaculture-related plastic pollution. Researchers are investigating ways to recycle or eliminate plastic equipment, with growing interest in bioplastics and degradable plastics as sustainable alternatives for use in aquaculture. By taking proactive steps to reduce plastic dependency in aquaculture, we can help protect marine life and move toward a cleaner, healthier ocean.

Fishing for a Solution

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