Novel study supports ban on pulse fishing

November 1, 2019 by Sophie Locke

Less than half the number of marine species were present in an area that had been fished with electric pulse trawls compared with areas where there was no pulse fishing, according to a 2019 study. There were also 2.6 times fewer common soles and almost half the amount of thornback rays in the pulse-fished area. The research conducted by the UK’s Centre for Environment, Fisheries and Aquaculture Science (Cefas) contains some of the first measurements that support the assertion by inshore fishermen that pulse trawling is destroying their fishing grounds and “leaving behind an aquatic graveyard”.

Electric pulse fishing is a method of commercial fishing where electrodes are attached a trawl net and dragged along the seabed, emitting electric charges and shocking marine life into the nets. Until recently, very little was known about the impact of pulse fishing on ecological communities, which is also an important step in determining how the practice affects inshore fishing grounds. This lack of scientific evidence was identified by the International Council for the Exploration of the Sea (ICES) in a 2018 report, stating that “there is insufficient evidence to fully understand the impact of electrical pulse on marine organisms and the benthic ecosystems across the North Sea.”

To address this knowledge gap, Cefas surveyed two fishing grounds: a region that has been previously fished by beam trawlers but has also experienced a recent increase in pulse trawl activity (Area 1) and a region with inshore fishing activity and no pulse trawling (Area 2). Two sampling methods were used: benthic trawls and otter trawls. Results showed that species richness, which is the number of different species in one area, was a staggering 57 per cent lower in Area 1 (the region with pulse trawling).

In benthic trawl samples, there was a notable absence of 17 different species in Area 1 compared to Area 2. This included species such as squid, queen scallop and tub gurnard. Otter trawl samples also identified a lack of 13 species in Area 1 compared to Area 2, including commercially valuable brown crab and horse mackerel. In their place was an abundance of brittle stars and hermit crabs, far higher in number than what was seen in Area 2.

While this destructive fishing method is to be banned by the EU in mid-2021, Dutch fishing fleets state the method is fuel-efficient and “environmentally friendly”. However, attempts to legitimise pulse fishing by the Dutch Government have been fraught with controversy. Earlier this year, one study discovered that an estimated 20.8 million EUR of direct subsidies had been “allocated to the development, support, and legitimisation of the Dutch electric trawling fleet since 2007.” The Dutch government had also issued 84 derogations to pulse trawlers, 70 of which were found to be illegal based on the five per cent limit that applies to the beam trawl fleet. These had been “issued under the guise of scientific research”, despite the fact there was no research plan in place.

Although the findings from Cefas highlight the damaging effect of electric pulse fishing, the report emphasises the need for more research to fully understand how this fishing method will impact marine ecosystems. In October 2018, this concern was central to the Blue Marine Foundation’s complaint to the European Commission regarding electric trawling in the Dogger Bank, one of Europe’s largest marine protected areas. Six months later, following a campaign by the Bloom Association and BLUE, the European Parliament has confirmed the illegality of electric pulse fishing from July 2021 and officially approved the ban.