In the relatively shallow waters of the upper Gulf of California in Mexico a ghostly menace has driven the world’s smallest porpoise to the brink of extinction: gill nets.
Only about 10 vaquitas remain and the outlook for the critically endangered species is bleak.
Entanglements with lost and illegal gill nets used to catch totoaba, another endangered fish whose swim bladder is prized on the black market, have decimated the population of tiny porpoises.
“The case of the vaquita clearly shows the dramatic impacts that ghost and illegal gill nets have in driving species to extinction,” says the World Wildlife Fund (WWF) in a report this week on ghost fishing gear. “We need to act urgently to avoid more marine species following the same path.”
Ghost gear — fishing equipment lost in the sea — can continue killing marine life for decades or even centuries after it first enters the ocean, making it the most deadly form of marine plastic debris, according to the report, Stop Ghost Gear.
At least 10% of marine litter is estimated to be made up of fishing waste, which means that between 500 000 and one million tons of fishing gear are polluting the ocean every year.
About 5.7% of all fishing nets, 8.6% of traps and pots, and 29% of all fishing lines used globally are lost every year. This “immortal menace” harms 66% of marine mammal species, half of seabird species and all species of sea turtle, “often subjecting them to a slow, painful and inhumane death”.
Valuable marine habitats such as coral reefs and mangroves are damaged, jeopardising people’s food sources and livelihoods. Ninety percent of the world’s fish stocks are now fully exploited, over-exploited or depleted. More than three million people depend on fish as a major source of protein.
“With a rising population, there is an increased demand for fish and therefore the use of fishing gear,” the report noted. “Gill nets, traps and pots, fish aggregation devices and other gear types are compounding the problem of plastics in our ocean as they end up abandoned, lost or discarded.”
Ghost gear must be central in the fight against plastic pollution. “Yet even as this crisis continues to intensify, little attention is being paid to it by governments or industry … While the unattended consequences of plastic use are finally beginning to receive attention, the impact of ghost gear are less seen and understood.”
South Africa’s coastal ghosts
Ghost fishing in South Africa, too, has not been given the attention it deserves, says Craig Smith, senior manager of the marine programme at WWF-SA. “But that does not mean that it does not occur and does not pose a threat to marine life.”
Any fisher, whether a subsistence, recreational or commercial, would have experienced the loss of fishing gear at some point, he says. “Every fisher would agree that they hate losing their fishing gear, but very few fishers agonise over the effect the gear continues to have on marine life and the environment.”
South Africa has the added problem of theft of marker buoys and a high energy coastline, which increases the risk of losing fishing gear such as lobster traps (hoops) and octopus pots.
“This has major consequences as the lost baited traps will slowly starve its captives, whereas lost octopus pot lines will provide high risk of entanglement for whales. Even well attended trap and pot fisheries poses a huge entanglement risk to whales,” he says.
In the tuna (swordfish) longline fisheries, radio beacons are regularly used along the mainline. When there is a break-off of the mainline the vessel is still able to locate and retrieve the lost gear.
“In octopus pot fisheries and lobster trap fisheries acoustic/ time release buoys should be used to reduce theft of buoys and reduce whale entanglements. These are examples of high-tech solutions for some of our more industrial fisheries.”
In some cases, Smith says, simple everyday measures can be effective: not dumping old fishing gear in the ocean, moving away from fishing spots that regularly ensnare fishing line or nets and ensuring that any ropes and box strapping used during fishing operations are free from forming loops and are responsibly discarded.
The Stop Ghost Gear report highlights “glaring gaps” in regulation at the global level with the existing framework lacking articulated global targets. “There is currently no obligation for states to develop and implement national action plans including the preventive, mitigation and curative measures needed to address ghost gear; no agreed standards for reporting and monitoring of plastics (including ghost gear); and no global financing mechanism to support measures to effectively eliminate discharge of plastics into the ocean.”
The United Nations Environmental Assembly has adopted four resolutions on marine litter and microplastics. “An effective global response to this crisis requires a comprehensive international treaty with clear obligations and responsibilities to prevent and reduce the influx of marine plastic pollution into the ocean. It must include ambitious targets, binding measures and sufficient support mechanisms,” the report states.
- 11 436 tons of traps and 38 535 tons of gillnets are abandoned every year in South Korean waters;
- An estimated 160 000 blue crab traps were lost every year in the Chesapeake Bay in the Atlantic Coastal Plain of the eastern United States between 2004 and 2008;
- More than 70km of gill nets were lost in Canada’s Greenland Halibut fishery in just five years; and
- About 5 500 to 10 000 gill net pieces were lost in the Baltic Sea each year between 2005 and 2008.