Industrial fishing is designed for efficiency, but some methods push efficiency to the point of destruction. Longline fishing, where fishing lines stretch for miles and carry thousands of baited hooks, doesn’t just catch target species like tuna or swordfish. It also kills sharks, turtles, seabirds, and countless other marine animals that were never meant to be caught.
What Is Longline Fishing?
Longline fishing uses main lines that can stretch for 30–50 miles, with thousands of branch lines hanging baited hooks into the water. These hooks are designed to target large, commercially valuable fish.
- Pelagic longlines: Float in the open ocean, targeting tuna, swordfish, and other large species.
- Demersal longlines: Rest near the seafloor, targeting groundfish like halibut and cod.
The efficiency is undeniable — but so is the collateral damage.
The Bycatch Problem
Bycatch refers to non-target species caught unintentionally. With longlines, bycatch is unavoidable.
- Sharks: Millions of sharks are hooked each year, often killed for their fins or discarded dead.
- Sea turtles: Endangered leatherbacks, loggerheads, and greens mistake bait for food. Once hooked, they drown or die from injuries.
- Seabirds: Albatrosses and petrels dive for baited hooks as they’re set, becoming snagged and drowned.
- Marine mammals: Dolphins and whales can become entangled in longlines.
Estimates suggest hundreds of thousands of non-target animals die annually because of longline fishing.
Why Longlines Are So Lethal
- Scale: Tens of thousands of hooks in the water at once multiply the chance of bycatch.
- Baited hooks: Attract a wide range of species, not just the targets.
- Slow retrieval: Hooks may stay in the water for hours or days, leaving trapped animals to suffer and die.
- Overlap with migration routes: Longlines are often set in the same areas turtles, sharks, and birds travel.
The very design of longlines guarantees collateral damage.
Species at Risk
Sea Turtles
- Six of the seven sea turtle species are threatened or endangered.
- Longlines are one of the leading causes of turtle mortality worldwide.
Sharks
- Pelagic longlines catch as many sharks as tuna in some regions.
- Populations of oceanic whitetip and silky sharks have declined by more than 90% in parts of the Atlantic and Pacific.
Seabirds
- An estimated 300,000 seabirds are killed by longlines each year.
- The wandering albatross, with a wingspan of 11 feet, is among the most threatened.
Swordfish and Tuna
- Even target species aren’t safe. Overfishing has left populations of bluefin tuna and swordfish deeply depleted.
Economic and Social Costs
- Fisheries collapse: Overfishing from longlines reduces stocks, threatening future supply.
- Lost tourism: Sharks and turtles generate billions through ecotourism but are killed by longlines.
- Community harm: Small-scale fishers can’t compete with industrial fleets that sweep oceans clean.
The short-term profits come at long-term ecological and social costs.
Solutions and Alternatives
Policy and Regulation
- Ban longlines in vulnerable areas, such as turtle migration routes and seabird nesting regions.
- Enforce bycatch reduction measures like hook modifications and seasonal closures.
Bycatch Mitigation Tools
- Circle hooks: Reduce turtle mortality compared to traditional J-hooks.
- Weighted lines: Make bait sink faster, reducing seabird interactions.
- Streamer lines: Scare birds away during setting operations.
Sustainable Alternatives
- Pole-and-line fishing, traps, and other selective methods reduce bycatch.
- Supporting small-scale fisheries helps supply seafood without wiping out ecosystems.
What You Can Do
- Avoid seafood linked to longline fishing (especially swordfish and some tunas).
- Look for credible certifications like MSC, though standards vary.
- Support organizations campaigning against destructive fishing practices.
- Shift diets toward lower-impact seafood like mussels, oysters, and seaweed.
Consumer choices ripple back into supply chains and policy.
FAQs
Is all longline fishing bad?
Some longline fisheries are managed better than others, but the method inherently risks high bycatch.
Can bycatch ever be eliminated?
No. Mitigation tools help, but as long as thousands of hooks are in the water, bycatch remains inevitable.
Why not just ban longlines?
Industry pressure and global demand for tuna and swordfish keep fleets operating. Some nations have banned longlines in their waters, but enforcement on the high seas is limited.
Are longlines used everywhere?
They are widespread in the Pacific, Atlantic, and Indian Oceans, particularly in international waters.
Final Thoughts
Longline fishing is one of the clearest examples of how industrial efficiency comes at an ecological cost. These miles-long lines, studded with thousands of hooks, don’t just bring in tuna and swordfish — they drag sharks, turtles, and seabirds toward extinction.
Ending or reforming longline fishing isn’t just about saving wildlife. It’s about protecting ocean ecosystems, preserving fisheries, and respecting the balance of life that sustains us all.
Reader Interactions