One of the most devastating problems caused by ghost gear is the entanglement and death of marine animals. Abandoned, lost, or discarded fishing equipment kills hundreds of thousands of marine mammals and sea turtles worldwide every year. But entanglement is just the beginning. Ghost gear also destroys coral reefs, generates microplastics, and creates serious hazards for boats and ships.
What Ghost Gear Actually Is
Ghost gear refers to any fishing equipment that has been abandoned, lost, or deliberately discarded in the ocean. This includes nets, traps, pots, longlines, and monofilament fishing line. Roughly 2% of all fishing gear ends up lost in the ocean each year. That translates to staggering numbers: nearly 3,000 square kilometers of gillnets, over 75,000 square kilometers of purse seines, more than 739,000 kilometers of longlines, and over 25 million pots and traps entering the water annually with no one controlling them.
Once in the water, this gear doesn’t stop working. Nets continue catching fish, traps keep luring animals inside, and lines keep tangling around anything that moves. The difference is that no one is hauling it in, so everything it catches simply dies.
Entanglement Kills Hundreds of Thousands of Animals a Year
Whales, dolphins, seals, sea lions, and sea turtles all become entangled in ghost gear as they swim or rest near shore. NOAA Fisheries identifies entanglement as a primary cause of human-caused death in several whale species, including right whales, humpback whales, and gray whales. For North Atlantic right whales, one of the most endangered large whale populations on Earth, entanglement in fishing rope is the single greatest threat to the species’ survival.
Entanglement doesn’t always kill quickly. An animal wrapped in netting or line may struggle for days or weeks, suffering deep lacerations as the gear cuts into skin and muscle. Some animals drown almost immediately. Others carry the gear with them, unable to feed properly, slowly starving as the lines restrict their movement or jaw. Sea turtles are especially vulnerable because they can mistake floating nets for food or swimming habitat, and their flippers tangle easily in monofilament line.
Ghost Nets Keep Fishing for Years
Lost nets don’t just sit on the ocean floor. They continue trapping fish, crustaceans, and other marine life in a cycle researchers call “ghost fishing.” A study examining abandoned gear in Turkish inland waters tracked nets over a full year and found they kept catching animals throughout the entire 360-day observation period. Monofilament nets were especially effective, capturing more than 22 kilograms of organisms during the experiment.
The cycle is self-reinforcing. A trapped fish attracts scavengers, which themselves become entangled. Their bodies then attract more scavengers, and the net fills with dead and dying animals continuously. Because modern fishing nets are made from synthetic materials like nylon, they don’t break down quickly. A nylon fishing net persists in the ocean for about 40 years. Monofilament fishing line lasts an estimated 600 years. That means a single lost net can ghost fish across decades.
Coral Reef Destruction
Ghost nets draped over coral reefs cause direct physical damage. They break coral branches, scrape against reef surfaces, and block sunlight from reaching the organisms below. NOAA researchers studying reef sites with ghost nets found significantly less living coral and more bare, dead substrate compared to net-free areas. Coral grows slowly, often just a few centimeters per year, so damage from a single net can set a reef back by decades.
The smothering effect is particularly harmful. A net settled over a reef creates a barrier that prevents coral polyps from feeding and exchanging gases with the surrounding water. Over time, the covered sections die off entirely, leaving behind exposed rock that algae colonize instead of new coral. This shifts the entire ecosystem away from the diverse, fish-supporting structure a healthy reef provides.
Microplastic Pollution
As synthetic fishing gear slowly degrades in saltwater, it fragments into smaller and smaller pieces, eventually producing microplastics that enter the food chain. The nylon used in most commercial fishing nets (known chemically as polyamide) is extremely durable. Depending on water temperature, nylon can take centuries to lose even half its structural strength. At 2°C, a temperature common in deep ocean waters, nylon would take roughly 1,000 years to degrade to half its original strength.
During that long breakdown, the gear also leaches chemical additives used in manufacturing. These chemicals accumulate in the tissues of small organisms that ingest the plastic particles, then concentrate further as larger predators eat those organisms. The result is a slow-moving contamination pathway that connects a lost fishing net on the seafloor to the fish on your dinner plate.
Hazards to Boats and Ships
Ghost gear isn’t only a problem for marine life. Floating or partially submerged nets and lines regularly foul boat propellers, block engine cooling water intakes, and wrap around rudders. A tangled propeller can dramatically reduce a vessel’s stability and ability to steer, creating dangerous situations especially in rough weather.
The scale of this problem is substantial. The South Korean navy recorded roughly 400 propeller entanglement incidents per year across its fleet of about 170 ships between 2010 and 2015, averaging 2.3 entanglements per ship annually. Japan documented over 32,000 incidents in a single year involving fishing vessel collisions with floating debris, clogged water intakes, and engine failures from fouled propellers. In the UK, a survey of harbor authorities found that 82% reported ghost gear incidents, with an average repair cost of several hundred dollars per event.
The consequences can be catastrophic. In 1993, a 110-ton ferry in South Korea capsized and sank after fishing rope caught in its propeller shaft, killing 292 of the 362 passengers aboard. In Shetland, the Royal National Lifeboat Institution conducted 286 rescues of fishing vessels with entangled propellers in a single year, at a cost exceeding €830,000. These aren’t rare edge cases. For any vessel operating in waters with commercial fishing activity, ghost gear is a persistent and unpredictable threat.