Pulse Trawling

Pulse trawling (also known as electro trawling and electric pulse trawling) is a technologically advanced – and highly controversial – method of commercial fishing which has only been used on an experimental basis up until now, but appears to making a major breakthrough into mainstream commercial fishing across Europe’s fisheries.

Pulse Trawl

A pulse trawl which uses electricity to shock fish out of the seabed.

Little research has been carried out into the long-term impact of this type of fishing and there are serious concerns over what pulse trawling does to fish stocks and the wider environment.

Development of Pulse Trawling

Pulse trawling is an adaptation of beam trawling, a method of commercial fishing which has been used for over one hundred years. Beam trawling is used to catch demersal species (those that live and feed on or near the seabed). The mouth of the net is held open by a solid metal bar and up to twenty ‘tickler chains’ thrash the seabed in front of the net to stir up fish (especially flatfish and prawns which bury themselves under the sand and silt of the seabed) which then allows them to be scooped into the net. Beam trawling is considered one of the most environmentally destructive forms of trawling by environmental groups such as Greenpeace due to the very high levels of bycatch and the damage to the seabed that this type of fishing causes.

Beam Trawl from 1893

Beam trawling has been around for well over a hundred years. This picture shows a beam trawl in action in 1893.

The pulse trawling system was invented by in the Netherlands by Piet Jan Verburg in 1992 and is an adaptation of beam trawling. This method of fishing replaces the tickler chains of traditional beam trawling with a series of electrical drag wires mounted into the net. These wires send electrical pulses into the seabed which cause the muscles of fish to contract and which forces the fish upwards and out of the seabed and into the net (1). The Dutch have remained the biggest proponents of pulse trawling and have advanced the use of this technology, claiming that pulse gear has less contact with the seabed meaning that there is more of the target species caught, lower levels of bycatch, less damage to the seabed and fish that are caught are in better condition and therefore reach a higher price at market. Furthermore, and the point that is of most interest to commercial fishermen, is that pulse trawls are up to ten times lighter than traditional beam trawl gear (2), meaning that fishing with pulse gear uses much less fuel than traditional beam trawling. Although it costs around £300,000 to convert a beam trawler to a pulse trawler and retrain the crew to use the new equipment (3), the savings that can be made mean that this investment can soon repay itself.

Pulse Trawling: Supposedly Banned by the EU but Increasing Across Europe

It is important to note that officially pulse trawling is banned by the European Union. Article 31 of Council Regulation (EC) No. 850/98 covers unconventional fishing methods and states:

“The catching of marine organisms using methods incorporating the use of explosives, poisonous or stupefying substances or electric current shall be prohibited.”

[Emphasis added].

Technically, this makes pulse trawling, or any kind of fishing using an electric current illegal anywhere within the waters of the European Union. However, a legal exception is made to allow pulse trawling to be carried out for research purposes.

This legal loophole has been heavily exploited by the Dutch fishing industry. They have lobbied to allow greater freedom to use pulse and electrical trawling gear and in 2010 they were partially successful in getting the restrictions on pulse trawling eased – a maximum of 5% of the Dutch commercial fishing fleet was allowed to use electrical fishing gear (3),. This may have seemed like a small rise but it meant a quadrupling of the number of pulse equipped vessels. In 2012, the amount of Dutch trawlers allowed to operate pulse trawls was increased to 10% of the fleet by the EU (3). This means that there are now over one hundred fishing vessels – the vast majority from the Netherlands – that have been converted into pulse trawlers despite the supposed EU ban on this type of fishing (2). Some of the conversions to transform fishing boats into pulse trawlers have even been funded by EU money (4). In a statement given to the BBC a spokesperson from the Government of the Netherlands Department of Agriculture said that the “relatively large number of participating vessels” was necessary because “the current assessment aims to investigate the long term effects of a large scale introduction of pulse fishing in the North Sea ecosystem” (5).

Due to the European Union’s Common Fisheries Policy the Dutch fishing vessels which are fitted with pulse trawls are allowed to fish anywhere within EU waters, which means they can operate up to twelve miles away from the British coastline. However, as the UK government still controls the twelve-mile zone around the Britain it has been able to stop pulse trawling from taking place within British inshore waters. This changed in 2015 when news emerged that twelve UK registered vessels had been equipped with pulse trawls and could therefore fish within the twelve-mile zone which the UK still controls (3). An article in the Guardian stated that at least some of these vessels had been financed by Dutch fishing companies (3).

It is not difficult to see why the Dutch fishing industry is pushing forward with pulse trawling, and why fishermen from other countries may also be keen to adopt the technology. The lighter fishing gear means huge fuel savings with one Dutch fisherman telling the BBC that he went from taking home €30,000 per year to €70,000 after equipping his fishing boat with pulse trawl equipment (5).

The Impact of Pulse Trawling

With the EU allowing – and in some cases funding – the expansion of pulse trawling many people would assume that it has been fully tested and proven to be a safe and low-impact method of fishing. However, many commercial fishermen, environmental campaigners and marine scientists point to the growing evidence that this is not the case, and the worrying lack of research into its long term impact. Commercial fishermen working out of ports in Kent and Essex reported that they were catching unusually high numbers of dead Dover sole and other flatfish in their nets in 2012. A Sunday Times article reported on this, with the fishermen interviewed placing the blame squarely on the Dutch pulse trawling fleet (6):

[It’s like] “fishing in a graveyard…What they don’t catch they annihilate…Virtually everything is dead.” – Tom Brown, Secretary of Thanet Fisherman Association.

 

“This is absolutely devastating for us because we never caught so many fish that [were] already dead…It’s a waste of time going to that area now. It stinks of dead fish.” – Jeff Loveland, owner of two fishing boats operating out of Ramsgate, Kent.

 

“I have fished there for 30 years and never seen anything like it. I think the pulse is killing the food in the seabed. Three years ago I caught 40 tons of sole in those grounds in one year. It was the best year we’ve ever had. There is nothing there now that I can catch.” – Roger Free, commercial fisherman from West Mersea, Essex.

There are also serious concerns that the spawning grounds of southern North Sea sole could be exploited by pulse trawling. This species comes into the soft ground in and around the Thames estuary to spawn – an area which is inaccessible to heavy traditional beam trawls. However, the lighter pulse trawls can work across very soft ground, and there is currently no way to stop Dutch pulse trawlers which have a quota to catch sole from fishing in this area during the spawning season (2).

Flatfish Buried in Seabed

Flatfish which bury themselves in the seabed are the main target of pulse trawlers.

The Low Impact Fishers of Europe (LIFE) a campaign group which represents small scale fishermen working across Europe are also seriously concerned about pulse trawling, pointing out that very little serious research has been carried out into the long term effects of fishing with electrical pulses, or the impact that it has on the wider marine environment. They point out that there is no way to control or regulate the power of the electricity which is used, or the frequency of the pulses which are emitted by the fishing gear (4). ICES (International Council for the Exploration of the Sea), the world-leading marine science organisation, states that pulse trawling could be a benign, ecological option for commercial fishing, but agrees that further research is needed to answer the “unresolved questions” over the impact that this type of fishing has on the marine environment (7).

The prominent environmentalist George Monbiot has been a long standing critic of pulse trawling. In 2015 he wrote an article in the Guardian entitled We Should be Outraged by Europe Slaughtering Sea Life in the Name of ‘Science’ and expanded on his views on pulse trawling in an interview for the BBC’s Newsnight programme in 2017. Monbiot is critical of the repeated claim that pulse trawling is less damaging that traditional beam trawling, not because it is untrue but because “beam trawling is so fantastically damaging to the seabed” that it is very easy to create a commercial fishing method which causes less damage (5).

An article published in the Independent in 2016 compared pulse trawling to fracking – the fracturing of underground rocks to release the gas they contain. Both are supposedly clean and safe but little research has been done into the medium and long term effects (8). In the same article it was claimed that the damage pulse trawling causes to the small creatures and food sources within the seabed may cause whole areas to become “fished out” if they are subjected to intensive pulse trawling (8).

Further evidence of the destructive potential of pulse trawling can be found from outside of Europe. Pulse trawling was used extensively in the East China Sea in the 1990s to catch shrimp. By the year 2000 there were around 10,000 beam trawlers working the area, around 3000 of which were equipped with pulse trawling gear (9). Catches of all kinds of shrimp, especially the burrowing species of shrimp, began to increase. However, lack of regulation meant that different levels of power were being used in the pulse gear, and it soon became apparent that damage was being caused to both juvenile shrimp populations and other benthic species (those that live in the seabed such as crabs, shellfish and starfish) (9). Pulse trawling was therefore banned in the seas around Zhejiang Province which had previously been the most common area for pulse trawling, and the rest of the East China Sea soon followed (9). Further evidence of the destructive impact of pulse trawling was gathered in 2013 when an article published in the peer-reviewed academic journal Fish and Fisheries found that pulse trawling had a serious impact on fish eggs and embryos in a freshwater environment (6).

Indeed, it is the lack of long-term research which is one of the most worrying aspects of pulse trawling and the knowledge gaps which still exist in the impact that this form of fishing has on the marine environment. In his BBC interview George Monbiot pointed out that if the Dutch have been equipping around one hundred fishing vessels with pulse trawling gear for scientific research there has been “no control area, no methodology, no way of assessing the results of this experiment” (5).

One serious impact of pulse trawling which has been verified by peer-reviewed scientific research is that large gadoid fishes (cod and related species such as haddock and whiting) which come close to pulse trawl gear can suffer from haemorrhages and muscular contractions which cause breakages of the spine (10). Tammo Bult, Director of the Wageningen Marine Research told the BBC that species such as shellfish, flatfish and sharks and rays did not appear to be affected by pulse trawling, but large cod which come to near to the pulse trawl gear can “have breakage of the spine … in that size of cod their own muscles break the spine” (5).

MSC Logo

The Dutch pulse trawl fishery only narrowly missed out on MSC certification.

Despite these concerns the Dutch plaice and sole fishery in the North Sea which uses pulse trawling was put forward for certification as a sustainable fishery by the MSC (Marine Stewardship Council) in 2016. There are three criteria assessed for MSC certification: healthy stocks, minimum ecosystem impact and effective management. A score of over 80 points must be reached in all three categories to be awarded certification. The fishery reached this in the healthy stocks and effective management category, but only scored 77 for minimum ecosystem impact, and was therefore not awarded the MSC certification (11). Despite this many conservationists, scientists and other groups who are opposed to pulse trawling will be concerned that a fishery based around pulse trawling can come so close to being able to refer to itself as an officially sustainable fishery.

The Future: Pulse Trawling Set to Become a Mainstream Fishing Method?

In July 2017 it was reported that pulse trawling was set to “get the green light” after a special meeting at the EU parliament. Elisa Roller, the Head of Unit at Directorate General Maritime and Fisheries Affairs of the European Commission was quoted as saying that pulse trawling was the “the most innovative, most researched and most fuel-efficient gear” (2) and was satisfied that enough research and testing had been carried out to make pulse trawling a mainstream fishing method throughout European waters (2).

Sole

No one knows what the long term impact of pulse trawling will be on species such as sole.

Many anglers, commercial fishermen, scientist and marine conservationists will be deeply concerned to hear that the European Union has taken so little notice of the many voices speaking out against pulse trawling and seems determined to expand this form of fishing across Europe with so little research about its medium and long term impact carried out.

For the UK the prospect of Brexit and leaving the European Union and the Common Fisheries Policy offers the possibility of regaining control of British territorial waters. If this was done then it would be perfectly possible for the UK government to ban all forms of pulse trawling and electro-fishing within UK waters, if the political will to do so was there. Professor Daniel Pauly, the world-renowned fisheries scientist is a prominent critic of the way that the EU has managed its fisheries and believes that Brexit offers the opportunity for the UK not only to ban pulse trawling but also to rebuild its fish stocks. He spoke about pulse trawling at a conference in London in January 2017 saying:

“The opportunity you have now is to do better than the EU has done . . . Trawling is very destructive gear, pulling everything in and destroying habitat and so on . . . But you can make things worse. You can add insult to injury by electrifying this thing. So the animals that would slip under the net get a spasm of electricity. They jump up and they are caught. So you can add to the things that you catch: the last worm, the last little shrimp in the sea. That is literally scraping the bottom of the sea” (12).

References:

  1. Project Pulsefishing – pulsefishing.eu
  2. Pulse Trawling Set to Get Green Light – Fishing News, 11th July 2017
  3. We Should be Outraged by Europe Slaughtering Sea Life in the Name of ‘Science’ – The Guardian, 9th February 2015
  4. Shocking the Fish – LIFE Platform
  5. Pulse Trawling – BBC Newsnight – 5th August 2017
  6. Zapped: Britain’s Fishing Graveyard – 24th June 2012
  7. Advice Released on the Effects of Pulse Trawling – ICES.dk, 4th February 2016
  8. Nature Studies: Pulse Fishing is the ‘Marine Equivalent of Fracking’ – The Independent, 14th March 2016
  9. Yu, C., Chen, Z., Chen, L., and He, P. (2007) The Rise and Fall of Electrical Shrimp Beam Trawling in the East China Sea: Technology, Fishery, and Conservation Implications. – ICES Journal of Marine Science, Volume 64, Issue 8, 1st November 2007.
  10. de Haan, J., Fosseidengen, J.E., Fjelldal, P. G., Burggraaf, D., Rijnsdorp, A. D. (2016) Pulse trawl fishing: characteristics of the electrical stimulation and the effect on behaviour and injuries of Atlantic cod (Gadus morhua). – ICES Journal of Marine Science, Volume 73, Issue 6, 1st June 2016.
  11. CVO Pulse Sole & Plaice, Marine Stewardship Council.
  12. The Wit and Wisdom of Daniel Pauly and Dirk Zeller, Transcript of a Press Briefing at the Science Media Centre, London – Blue Marine Foundation, 18th January 2017.

Note: This article was originally published in 2012 and was extensively rewritten in 2017 to account for developments which taken place in pulse trawling.

Share this page: