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Lookup NU author(s): Dr Andrew Temple, Emeritus Professor Per Berggren
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2026 Society for Marine Mammalogy. Gillnet bycatch is the primary global threat to marine mammals. In this study, the effectiveness of upcycled plastic bottles used as acoustic reflectors to reduce dolphin bycatch and their effect on target catch was evaluated. Observed trials with (treatment) and without (control) bottles in bottom-set trammel nets and bottom-set gillnets were conducted between November/2020 and April/2025. Across 318 sets (170 control; 148 treatment), bycatch per unit effort (BPUE; based on net length × soak time) was 7.14 × 10−7 in control sets and 0.86 × 10−7 in treatment sets, representing an 88% reduction in BPUE when acoustic reflectors were used. Mean catch of target species did not differ significantly between control (=107 ± 92 kg) and treatment (=118 ± 141 kg) sets. Acoustic monitoring showed that average franciscana dolphin (Pontoporia blainvillei) click detections, measured as detection positive minutes (DPM), did not differ significantly between control (DPM = 0.0125) and treatment (DPM = 0.0128) sets. These results demonstrate that plastic bottles used as acoustic reflectors in bottom-set trammel nets and gillnets reduced the bycatch of dolphins and had no effect on the catch of target species. Given its low cost and lack of impact on target-species catch, this method can be readily tested in other regions and, if effective, widely adopted to improve the conservation of coastal dolphin species.
Author(s): Sucunza F, Barth A, Danilewicz D, Dolman S, von Fersen L, Larre GG, Mangel JC, Ott PH, Alfaro-Shigueto J, Temple AJ, Tregenza N, Berggren P
Publication type: Article
Publication status: Published
Journal: Marine Mammal Science
Year: 2026
Volume: 42
Issue: 3
Print publication date: 01/07/2026
Online publication date: 18/05/2026
Acceptance date: 20/04/2026
Date deposited: 17/07/2026
ISSN (print): 0824-0469
ISSN (electronic): 1748-7692
Publisher: John Wiley and Sons Inc.
URL: https://doi.org/10.1111/mms.70189
DOI: 10.1111/mms.70189
ePrints DOI: 10.57711/07mq-ee14
Data Access Statement: The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.
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