Bycatch Basics
Bycatch – the unintentional capture of marine life in fishing gear – is one of the greatest threats to ocean biodiversity worldwide. But proven, practical solutions already exist for every major gear type.
What is bycatch?
Bycatch is the unintentional capture of non-target species during commercial fishing operations. This can include marine mammals, sea turtles, seabirds, sharks, rays, and juvenile fish.
It happens across every major fishery in the world — from small-scale coastal operations to industrial fleets. The scale of the problem is significant, but so is the opportunity to address it.
Species at Risk
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Sea Turtles
Six of seven sea turtle species are threatened or endangered. Longlines, gillnets, and trawls are the primary gear types that interact with turtles. Solutions like circle hooks and turtle excluder devices (TEDs) have dramatically reduced bycatch in many fisheries. -
Marine Mammals
Dolphins, whales, seals, and sea lions are caught in gillnets, purse seines, and trawls worldwide. Acoustic deterrent devices (pingers) and gear modifications have proven effective at reducing mammal bycatch in key fisheries. -
Seabirds
Albatrosses, petrels, and other seabirds are drawn to baited hooks on longlines and caught in trawl cables. Bird-scaring lines (tori lines), weighted hooks, and night setting are cost-effective solutions already in use across many fleets. -
Sharks and rays
Sharks and rays are caught as bycatch in longline, purse seine, gillnet, and trawl fisheries globally. Many species are slow to reproduce, making populations especially vulnerable. Shark-specific hooks, magnetic deterrents, and handling best practices are reducing mortality.
Gear Types
Different fishing gear types create different bycatch challenges — and each has specific, proven solutions. Explore the gear types below to learn how bycatch happens and what’s being done about it.
Gillnets
Gillnets
Vertical mesh walls that entangle fish by their gills. Since gillnets are difficult to see and non-selective, they can account for staggering amounts of bycatch.
Longlines
Longlines
Miles of line with hundreds of baited hooks. Non-target animals can get hooked while attempting to eat the bait.
Pots and Traps
Pots and Traps
Baited enclosures set on the seafloor. Buoy lines can get wrapped around the fins and body of large whales and sea turtles, leading to serious injury and death.
Purse Seines
Purse Seines
Large nets that encircle entire schools of fish. Non-target species can get caught inside the net once it is pursed.
Trawlers
Trawlers
Cone-shaped nets dragged through the water. The nets scoop up anything in their path, including non-target species, and can also destroy seafloor habitats.
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Every partnership, every funded project, and every solution deployed brings us closer to fisheries that work for both people and the ocean.