Netherlands request - Electric Pulse Trawl
Based on the expert reviews, ICES concludes that:
1. The experiments are a valuable further step to evaluate the ecosystem effects of fishing with pulse trawls.
2. Laboratory experiments on elasmobranches, benthic invertebrates, and cod to test the effects of electric pulses were generally well designed and interpreted correctly. However, the experimental results have some weaknesses as discussed below.
3. The experiments indicate minimal effects on elasmobranches and benthic invertebrates.
4. Electric pulses resulted in vertebral injuries and death of some cod which were in close proximity (<20 cm) to the conductor emitting the electric pulses. There is inconclusive evidence that the capture efficiency of cod by pulse trawls is higher than for conventional beam trawls (see attached review by Norman Graham). Widespread use of the pulse trawl has the potential to increase fishing mortality on cod as a result of injuries caused by electric pulses (and possibly higher capture efficiency) but further research is needed to draw firm conclusions.
5. While the results of laboratory experiments are informative, many factors could result in different effects during actual fishing operations. In particular, specifications contained in the derogation for the pulse trawl allow a wider range of electric pulse characteristics than were tested in the experiments. Therefore, pulse trawls permitted under the EC derogation may generate substantially different effects than those observed in the experiments.
6. This advice is narrowly based on the review of three reports provided by The Netherlands. Concerns and uncertainties raised in the advice may be addressed by further research, refinement of the derogation, and monitoring the fishing operations and performance of vessels using pulse trawls.
Published under the auspices of the following ICES Steering Group or Committee