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📰 The quick summary: Sealing recycled plastic bottles onto bottom-set fishing nets reduced accidental dolphin bycatch by 88% in Brazilian trials, offering small-scale fisheries a nearly free conservation tool that does not cut commercial catch.
📈 One key stat: Dolphin bycatch dropped by 88% in nets fitted with recycled plastic bottles compared to standard nets, without any meaningful reduction in the fishers’ commercial catch.
💬 One key quote: Per Berggren, an emeritus professor of marine megafauna conservation at Newcastle University, described the approach as “recycling that rescues dolphins.”

1️⃣ The big picture: Every year, at least 300,000 dolphins, porpoises, and whales die after becoming entangled in fishing gear, with gillnets posing one of the greatest dangers because their thin nylon mesh returns a weak echolocation signal. Researchers in Brazil found that attaching sealed, recycled plastic bottles to bottom-set gillnets can fix that problem cheaply, since the air pocket inside each bottle reflects underwater sound up to 1,000 times more strongly than the surrounding mesh, making the net far easier for dolphins to detect. A large follow-up study covering 318 net sets off southern Brazil recorded 88% less dolphin bycatch per unit of fishing effort in bottle-equipped nets, with no significant drop in commercial catch. The technique is especially promising for small-scale fishing communities because it requires no batteries, electronics, or expensive equipment. Earlier trials in Peru and Zanzibar showed mixed results, so researchers stress that local conditions, particularly water depth and background noise levels, play a major role in whether the method works.

2️⃣ Why is this good news: An 88% reduction in accidental dolphin deaths represents a major step forward for cetacean conservation in small-scale fisheries, where expensive electronic pingers have long been out of reach for most boat owners. Because the bottles cost virtually nothing and can be made from waste plastic that might otherwise end up on a beach, the approach turns a pollution problem into a conservation solution. Commercially valuable fish catches were unaffected in the Brazilian trials, removing the main economic barrier that has historically made fishers reluctant to adopt bycatch reduction gear. Vulnerable species like the franciscana dolphin, already under serious pressure from gillnet entanglement, could see meaningful population relief if the method scales across coastal fisheries in South America. Ongoing trials in Cambodia and the Republic of the Congo suggest the technique has the potential to protect dolphins across multiple ocean regions and fishing cultures.

3️⃣ What’s next: Researchers are currently running trials in Cambodia and the Republic of the Congo to test whether the Brazilian results hold in different fishing systems and coastlines. Any wider rollout will require training for fishing communities, monitoring programs, and careful local testing to confirm the bottles perform well with the specific nets, dolphin species, and water conditions present. Scientists are also working to better understand exactly why the method succeeded in deep, quiet bottom-set fisheries but not in noisier surface waters, so future deployments can be targeted more precisely.

Read the full story here: ECOticias – Recycled plastic bottles could reduce accidental dolphin bycatch in fishing nets by up to 88%, a pretty wild twist for a waste material usually linked to pollution