Every year, commercial fishing operations kill an estimated 300,000 whales, dolphins, and porpoises, along with hundreds of thousands of sea turtles, sharks, and seabirds — not because fishers want them, but because the animals end up tangled in nets and hooked on longlines meant for tuna, swordfish, and shrimp. The industry calls it bycatch. Conservationists call it an ecological catastrophe. And now, a growing body of research suggests that relatively simple, inexpensive technologies — LED lights, weak hooks, electrified metals, and artificial intelligence — could dramatically reduce this collateral damage without gutting fishers’ livelihoods.
The scale of the problem is staggering. Bycatch accounts for roughly 10% of the global catch, according to the Food and Agriculture Organization of the United Nations. Some fisheries are far worse. Gulf of Mexico shrimp trawlers historically discarded four pounds of marine life for every pound of shrimp they kept. For endangered species already under pressure from habitat loss, climate change, and pollution, bycatch can be the difference between recovery and extinction.
A comprehensive review published in March 2026 in the journal Science, led by researchers at Arizona State University, the National Oceanic and Atmospheric Administration, and several international institutions, examined decades of bycatch-reduction research and cataloged the most promising interventions. As Ars Technica reported, the paper represents one of the most thorough assessments to date of what actually works — and what fishers might realistically adopt.
The findings are encouraging. Not because there’s a single silver bullet, but because dozens of targeted solutions are proving effective across different fisheries, gear types, and species.
Start with light. Green LED lights attached to gillnets — those curtain-like walls of mesh that hang in the water column — have shown remarkable results in reducing sea turtle entanglement. Studies off the coast of Baja California, Mexico, found that illuminated nets reduced turtle bycatch by as much as 70% while barely affecting the target catch of fish and crustaceans. The reason is elegantly simple: sea turtles can see the lights and avoid the nets, while many commercially valuable fish species are either attracted to or indifferent to the illumination. The lights cost a few dollars each, run on small batteries, and last for months.
Jesse Senko, a marine biologist at Arizona State University and lead author of the Science review, told Ars Technica that illuminated nets have been tested across multiple regions and consistently deliver significant reductions in turtle and seabird bycatch. The technology is already being deployed in some Mexican fisheries, and trials are underway in Indonesia, Peru, and the Mediterranean.
But light isn’t the only sensory trick researchers are exploiting.
Sharks and rays possess electroreceptors — specialized organs called ampullae of Lorenzini that detect weak electrical fields produced by the muscle contractions of nearby prey. Researchers have turned this biological feature against the animals’ own curiosity. By attaching small electropositive metals or low-voltage electrical devices to hooks and nets, scientists can create fields that overwhelm these receptors, effectively repelling sharks and rays without harming them. According to the Science review, electrified deterrents have reduced shark bycatch in some longline fisheries by 30% to 50%.
The concept sounds high-tech. The execution is surprisingly low-fi. Some designs use nothing more than rare-earth metals that generate a mild galvanic current when submerged in saltwater. No batteries required. No moving parts. Just chemistry.
Then there’s the question of hooks themselves. Longline fishing — where a single vessel may deploy lines stretching 60 miles with thousands of baited hooks — is a major source of turtle, shark, and seabird mortality. One of the simplest interventions involves switching from traditional J-shaped hooks to circle hooks, which are designed to catch in the corner of a fish’s mouth rather than being swallowed. Sea turtles hooked with circle hooks are far more likely to survive, and the hooks are easier to remove. The Science paper noted that circle hooks have been mandated in several U.S. fisheries and are gaining traction internationally.
Weak hooks offer another approach. These are hooks manufactured to straighten under a certain amount of force — enough to hold a target species like tuna, but not enough to restrain a large sea turtle, shark, or marine mammal. The animal essentially pulls itself free. Field tests in the Atlantic and Pacific have demonstrated meaningful reductions in bycatch of non-target species with minimal loss of commercially valuable fish.
Seabirds present their own challenges. Albatrosses, petrels, and shearwaters are drawn to the bait on longline hooks as they’re deployed behind vessels. The birds dive for the bait, get hooked, and drown. An estimated 100,000 seabirds die this way annually. Solutions here are mechanical rather than sensory. Bird-scaring lines — called tori lines — stream behind the vessel during hook deployment, creating a visual barrier that deters birds from approaching the baited hooks. Weighted lines that sink baits faster also help, reducing the window of time when hooks are accessible near the surface.
These aren’t theoretical concepts. They’re already saving birds. In the Southern Ocean, where longline fleets target Patagonian toothfish (marketed as Chilean sea bass), mandatory use of tori lines and weighted hooks has cut seabird bycatch by over 90% in some fisheries, according to the Commission for the Conservation of Antarctic Marine Living Resources.
So the technology works. The harder question is adoption.
Fishers operate on thin margins. Any modification to gear or practice that adds cost, complexity, or reduces catch — even temporarily — faces resistance. The Science review emphasized that bycatch-reduction technologies must be co-developed with fishing communities, not imposed from above. Senko and his colleagues argued that the most successful interventions are those where fishers themselves participated in testing and refinement, because they understand the practical realities of deploying gear in rough seas, at night, in remote waters.
Cost matters enormously. LED lights at a few dollars per unit are an easy sell. Retrofitting an entire longline operation with specialized hooks and electrical deterrents is a different proposition. Government subsidies and certification programs — like the Marine Stewardship Council’s sustainability label — can help offset costs, but coverage remains uneven. Many of the world’s most destructive fisheries operate in developing nations where regulatory capacity is limited and enforcement spotty.
Artificial intelligence is beginning to change the calculus. Computer vision systems mounted on vessels can now identify species in real time as nets are hauled aboard, providing data that was previously available only through expensive onboard observer programs. Some systems can detect the presence of protected species on sonar or underwater cameras before nets are even set, allowing fishers to move to a different location. As Ars Technica noted, AI-powered monitoring also makes it possible to verify compliance with bycatch regulations remotely, reducing the need for human observers on every vessel.
NOAA has been investing in electronic monitoring systems for several years, and the agency’s fisheries division has piloted camera-based programs in the Atlantic pelagic longline fleet and the Pacific groundfish trawl fishery. Early results suggest the technology can match or exceed the accuracy of human observers for species identification, at a fraction of the cost.
The geopolitical dimension can’t be ignored. The United States, European Union, Australia, and New Zealand have some of the world’s most stringent bycatch regulations. But much of the global fishing effort — particularly in the high seas and in the waters of developing nations — operates under minimal oversight. Illegal, unreported, and unregulated fishing remains rampant. Technologies that reduce bycatch are meaningless if they’re not deployed on the vessels doing the most damage.
International frameworks are slowly catching up. The United Nations’ agreement on biodiversity beyond national jurisdiction, finalized in 2023, includes provisions for environmental impact assessments of fishing activities on the high seas. And the World Trade Organization’s 2022 agreement on fisheries subsidies, while limited in scope, represents the first multilateral trade rule targeting environmental harm from fishing. Whether these agreements translate into actual reductions in bycatch depends entirely on implementation — and that’s where optimism meets reality.
There are success stories worth studying. The Hawaiian longline swordfish fishery was shut down in 2001 after excessive interactions with endangered loggerhead and leatherback sea turtles. When it reopened in 2004 with mandatory circle hooks and mackerel bait (replacing squid, which turtles find irresistible), turtle bycatch plummeted. The fishery has operated continuously since, with turtle interaction rates far below regulatory limits. It’s a proof of concept that well-designed regulations, informed by science and accepted by industry, can work.
Australia’s prawn trawl fisheries offer another model. Turtle excluder devices — metal grids installed in trawl nets that allow turtles to escape through an opening while shrimp pass through to the cod end — have been mandatory since the 1990s. Bycatch reduction devices that allow fish and other non-target species to escape have been progressively refined and required. The result: dramatic reductions in bycatch with the fishery remaining commercially viable.
The picture isn’t uniformly positive. Some species are proving harder to protect. Small cetaceans — harbor porpoises, Hector’s dolphins, vaquitas — are extremely vulnerable to gillnet entanglement, and acoustic deterrents (pingers) attached to nets have shown mixed results. The devices work in some contexts but not others, and habituation — where animals stop responding to the sound over time — remains a concern. For the vaquita, the world’s most endangered marine mammal with fewer than a dozen individuals remaining in Mexico’s Gulf of California, the only viable solution appears to be eliminating gillnet fishing entirely within its habitat. Technology has its limits.
What the Science review makes clear is that bycatch reduction is not a single problem with a single answer. It’s hundreds of problems across thousands of fisheries, each requiring tailored solutions. The good news is that the toolkit is expanding rapidly. LED lights, circle hooks, weak hooks, electropositive metals, tori lines, turtle excluder devices, acoustic pingers, real-time AI monitoring, predictive habitat modeling — each addresses a specific interaction between a specific gear type and a specific group of animals.
The bad news is that deployment lags far behind invention. Many of these technologies have been validated for years, even decades, without achieving widespread adoption. Bridging that gap requires money, political will, and — perhaps most critically — genuine partnership with the millions of small-scale fishers who account for the majority of global fishing effort and often lack the resources or incentives to change their practices.
Senko and his co-authors called for a “moonshot” approach to bycatch reduction: coordinated international investment in research, development, and deployment of proven technologies, coupled with stronger regulatory frameworks and market-based incentives. The analogy is aspirational, but the underlying argument is practical. The technologies exist. The science is solid. What’s missing is the institutional machinery to put them in the water at scale.
For an industry that feeds billions of people and supports livelihoods in virtually every coastal nation, the stakes extend well beyond conservation. Bycatch degrades the marine food web that commercial fisheries depend on. It damages the reputation of seafood brands in an era when consumers increasingly demand sustainability credentials. And it creates legal and regulatory risk for fleets that operate in or export to jurisdictions with strict environmental standards.
Reducing bycatch isn’t charity. It’s self-interest, properly understood.
The ocean is not an infinite resource, and the species being killed as collateral damage — turtles that take decades to mature, albatrosses that range across entire ocean basins, sharks whose populations recover with agonizing slowness — are among the most vulnerable to overexploitation. The tools to protect them while keeping fisheries productive are no longer speculative. They’re sitting on laboratory shelves and in pilot programs, waiting for the scale of deployment to match the scale of the problem.
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