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Upcycled glass and plastic bottles offer potential low-cost mitigation to megafauna bycatch in gillnet fisheries

Lookup NU author(s): Emeritus Professor Per BerggrenORCiD, Dr Matthew Sharpe, Professor Jeffrey NeashamORCiD, Dr Andrew Temple

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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Abstract

© 2026 The AuthorsBycatch in gillnet fisheries represents the primary threat to cetaceans globally, yet mitigation has been hampered by a lack of effective, affordable solutions. Here we tested upcycled glass and plastic drink bottles as low-cost bycatch mitigation devices (mechanical pingers and acoustic reflectors, respectively) in gillnet fisheries across three regions. Observed trials were conducted in surface-set driftnet fisheries targeting teleosts and elasmobranchs off Zanzibar, East Africa, and Peru (2017–2021), and in bottom-set trammel net fisheries targeting teleosts off Brazil (2020–2022). Glass and plastic bottle treatments were tested against control sets across 1107 and 456 drift net sets in Zanzibar and Peru respectively, and 105 trammel net sets in Brazil. Catch differences between treatment and control sets were analysed using generalised linear hurdle and mixed models. Plastic bottles showed promise in Brazil, potentially reducing dolphin bycatch while increasing fish catch, though further trials are needed to confirm this. In Peru, glass bottles had no effect on dolphin, porpoise, or turtle bycatch but altered elasmobranch and teleost catches; plastic bottles similarly had no effect on dolphin bycatch but increased shark catch. In Zanzibar, no dolphin bycatch was recorded in any sets, though plastic bottles increased tuna catch. Overall, our results suggest plastic bottles may reduce dolphin bycatch in bottom-set fisheries, but neither device showed efficacy in surface-set fisheries. We encourage further trials of these and similar low-cost devices as accessible mitigation tools for small-scale fisheries.


Publication metadata

Author(s): Berggren P, Alfaro-Shigueto J, Mangel JC, Sharpe M, Jiddawi NS, Neasham J, Larre G, Temple AJ

Publication type: Article

Publication status: Published

Journal: Fisheries Research

Year: 2026

Volume: 298

Print publication date: 01/06/2026

Online publication date: 09/05/2026

Acceptance date: 30/04/2026

Date deposited: 24/08/2026

ISSN (print): 0165-7836

ISSN (electronic): 1872-6763

Publisher: Elsevier B.V.

URL: https://doi.org/10.1016/j.fishres.2026.107748

DOI: 10.1016/j.fishres.2026.107748

Data Access Statement: Data will be made available on request.


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Funding

Funder referenceFunder name
KAUST Global Fellowship Program under Award No. ORA-2022–5001
US Marine Mammal Commission (Grant MMC18–162)
US NOAA Bycatch Reduction Engineering Program (BREP) (Grant NA18NMF4720298)
WIOMSA (Grant MASMA/CP/2014/01)
WWF UK (Project number GB085402 for trials in Zanzibar, East Africa).

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