Until the 1980s, fishermen who fished for swordfish off the coast of California used harpoon guns to reel in their prey. As the industry modernized, the guns were exchanged for drift gillnetsgigantic nets the size of the Golden Gate Bridge that hang vertically in the water. By 1985, the catch reached a historic high, with fishermen landing more than 2,000 metric tons of fish. But there was a tragic and underdiscussed consequence of that approach.
A drift gillnet catches far more than just the target fish. It scoops up any marine animal unfortunate enough to swim in its path, including whales, dolphins and other marine mammals like seals and sea lions. Turtles, sharks, fish and even seabirds are also, inadvertently, trapped and killed by these nets. No surprise that environmentalists have dubbed them invisible curtains of death. But what may be surprising to many is that California is the last state in the nation to permit this destructive and unsustainable fishing method.
Turtle Island Restoration Project, a California-based international marine conservation organization, has been campaigning to end the use of drift gillnets, also called driftnets. Last year, they released a report titled California Driftnet Fishery: The True Costs of a 20th Century Fishery in the 21st Century that details the impact the state’s driftnet fishery has on marine wildlife.
While the fishery’s primary target is swordfish, the report reveals a shocking statistic: Only one in eight animals caught by the fishery is actually a swordfish. The unlucky, non-targeted species trapped by the nets are known as bycatch.
According to the report:
Over the past ten years, nearly a thousand air-breathing whales, dolphins and sea turtles have drowned, while thousands of sharks (that depend on constant movement) have suffocated. In the last ten years, an estimated 26,000 sharks overall were caught by this deadly fishery, with nearly 10,000 simply being tossed overboard.
The fishery was especially wasteful in its treatment of blue sharks. In the last decade, 8,186 blue sharks were caught, and an astounding 8,180 were discarded. Of those discarded, nearly 5,313 were dead. The fishery also caught an astounding 8,000 common thresher sharks (a candidate species for listing under the U.S. Endangered Species Act) and is further jeopardizing shark populations.
The report also found that, over the last decade, the fishery has killed around 900 marine mammals, among them bottlenose dolphins, gray whales, humpback whales, California sea lions and elephant seals.
Remarkably, the California driftnet fishery comprises less than 20 boats, yet ranks among the worst 20 percent of all fisheries globally: The total combined bycatch of all the other fisheries on the West Coast would still not amount to the bycatch of this single fishery. Even more concerning is the heavy toll this fishery has taken on endangered species: One in every five animals caught in driftnets is listed as “threatened” on the Red List of the International Union for the Conservation of Nature. Over the past 10 years, more than 20 critically endangered leatherback and loggerhead sea turtles have perished in California’s deadly nets.
“If these animals were washing up on our beaches and shores, we would be outraged,” said Joanna Nasar, Turtle Island spokesperson. “But because this fishery operates secretly off our coast, it is harder to see the impact.”
The trouble isn’t limited to California. Driftnets are used around the world and have caused the unintentional deaths of an untold number of marine animals.
In 2014, the Natural Resources Defense Council released a report, Net Loss: The Killing of Marine Mammals in Foreign Fisheries, which found a wide array of marine mammal species around the globe killed by the nets, from sperm whales in the Mediterranean, spinner dolphins in the Indian Ocean and false killer whales off the coast of Hawaii.
For marine mammal populations, the problem is truly global, with at least 75 percent of all toothed whales species (like dolphins and porpoises), nearly 65 percent of baleen whale species (like humpback and right whales), and more than 65 percent of pinniped species (like sea lions) suffering from gillnet bycatch over the past 20 years, said NRDC spokesperson Kimiko Martinez, in an email.