Request from France for updated advice on the ecosystem effects of pulse trawl
ICES concludes that:
1. Conventional beam trawling has significant and well demonstrated negative ecosystem impacts. If properly understood and adequately controlled, electric pulse stimulation may offer a more ecologically benign alternative and could reduce fishing mortality on non-target species. However, it is unclear whether the current legislative framework is sufficient to avoid the deployment of systems that are potentially harmful for some marine ecosystem components (e.g. cod). While the systems currently used do not appear to have major negative impacts, ICES considers that the existing regulatory framework is not sufficient to prevent the introduction of potentially damaging systems.
2. Technological developments have resulted in pulse trawl systems requiring less power (typically less than 1 kW per m gear width of beam length) and new trawl designs (SumWing, PulseWing) that reduce the pressure on the seabed. However, operational issues such as the determination of critical pulse characteristics (power, shape, frequency, etc.) to determine thresholds which ensure environmental sustainability, remain unresolved. ICES therefore advises to undertake structured experiments that are able to identify the key pulse characteristics and thresholds below which there is no evidence of significant long-term negative impact on marine organisms and benthic communities. ICES also recommends that as part of the regulatory framework, information on the pulse parameters used during fishing operations is made available to the scientific community as this information is needed to conduct assessments of the ecological impact of the pulse fisheries.
3. Questions remain for target and non-target species regarding delayed mortality and long-term population effects as well as sub-lethal and reproductive effects of electric trawls. Recent experiments on pulse trawling in saltwater conditions have expanded the knowledge base significantly (additional species, life stages, reproduction, feeding behaviour) and provided greater insight into more medium-term effects. It is unclear whether the injuries observed in cod are restricted to cod or potentially have an impact on all gadoids.
4. ICES recommends that a research programme should be set up to address outstanding issues, including long-term and/or cumulative effects of flatfish and shrimp pulse trawling.
5. ICES advises not to generalize from the results of the research carried out to date to allow expansion of the use of the pulse trawl outside the current area and fisheries allowed for in the current legislation. Extending the use of similar technology in other fisheries without a comprehensive environmental impact assessment would not be consistent with the precautionary approach. ICES considers that opportunities to trial fishing by electrical means in other fisheries should be made available in a structured, incremental way to allow for such impact assessments.
6. The risk of negative impacts on species and habitats covered by the Natura 2000 directives is considered low in the current area fished and with the current pulse characteristics.
Published under the auspices of the following ICES Steering Group or Committee