Analysis on Bycatch Mitigation Measures and Alternative Fishing Methods Published

Bonn, 21 December 2021 - A new ASCOBANS report detailing a cost-benefit analysis for mitigation measures in fisheries with high bycatch is launched today.  The report, authored by Fiona L. Read, reviews the implementation cost and pros and cons of different bycatch mitigation measures and alternative fishing methods.

Bycatch is the major threat to cetacean conservation and welfare in European waters. The common dolphin (Delphinus delphis) and the harbour porpoise (Phocoena phocoena) are often reported as bycaught in the ASCOBANS Agreement Area, although all small cetaceans are affected. Fishing gear that results in highest bycatch levels are static nets (i.e., gillnets and entangling nets) and trawl nets. Bycatch not only negatively impacts the conservation status of cetacean species, but also damages the nets, causing financial losses, and is time-consuming and dangerous to fishers.

At present, acoustic deterrent devices (‘pingers’) are the only mitigation method in the ASCOBANS region proven to have up to 100% bycatch reduction. Mitigation measures examined in this report included acoustic deterrent devices, porpoise alerting devices, reflective nets, acrylic echo enhancers, lights, and various technical modifications and changes to fishing practices.  Nevertheless, no mitigation measure will be sufficient if countries do not comply with their legal obligations to mitigate cetacean bycatch.

All of the alternative gears proposed in the report are Low Impact Fuel Efficient (LIFE) gears, which are designed to minimise fuel consumption and enhance the economic viability and environmental sustainability of fishing operations. LIFE gears improve the management of resources and minimise long-term costs for the fishers, and can provide similar hauling and setting efficiency than static nets and trawls.

Successful mitigation measures and the implementation of alternative gears can only be achieved with collaboration between fishers, government, and scientific institutions. For fisheries to be sustainable, economically profitable, and viable, countries will need to implement mitigation measures in all gears with high levels of cetacean bycatch. 

The report was peer-reviewed by Barry Baker, Sheryl Hamilton, Russell Leaper, Eunice Pinn, and Peter Evans. The report was also consulted with the Joint Bycatch Working Group of ASCOBANS and ACCOBAMS, and will be shared widely.  The Secretariat would like to give a warm thank-you the author, the reviewers, and everyone who contributed to this report. The Secretariat hopes that the report will be of interest to stakeholders, and foster collaboration on the implementation and trial of bycatch mitigation measures and alternative gears.


Fiona L. Read (2021). Cost-benefit Analysis for Mitigation Measures in Fisheries with High Bycatch. ASCOBANS Secretariat, Bonn, Germany. 52 pages. ASCOBANS Technical Series No. 2.


Last updated on 21 December 2021

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United Kingdom
Atlantic Ocean
Baltic Sea
North Sea