My two cents on the pulse ban

As I am writing this the European Parliament, the European Council, and the European Commission are still discussing a ban on pulse fishing. Dutch fishers have invested millions of euros in this technology, assuming they would be able to use it for many years to come. And judging by the scientific results so far, they had every reason to do so: pulse trawls have lower fuel use, lower CO2 emissions, less penetration of the sea floor, lower bycatch of plaice than traditional beam trawls. So no wonder they are angry and frustrated at the prospect of a ban.

Most likely it will come to pass. There are plenty of articles on how The Netherlands have lost the battle for the hearts and minds of other EU member states, such as this article in a Dutch newspaper, or this paper by my colleagues at Wageningen University (paywall – sorry!). By and large the experts seem to agree that the Dutch government dramatically overplayed its hand, and that a more careful introduction of the technology may have been more effective in the long run. I can’t judge this but I have two reflections.

Don’t people ever listen?

First, the scientists working on the effects of pulse trawling are also frustrated, and it’s a frustration I also sense with respect to other societal debates. By and large, the scientific consensus is that pulse trawling is most likely better than its alternative, beam trawling:

  • “No injuries were found in fish exposed to the electrical pulses.” (Soetaert et al., 2018, North American Journal of Fisheries Management)
  • “Exposure of Sole embryos at 2 d postfertilization and larvae at 11 d posthatching to pulsed DC used to catch brown shrimp did not result in a lower survival 8 d after exposure. Additionally, no differences in yolk sac resorption and morphometric length measurements of the notochord, muscle, eye, and head were observed in the developing larvae.” (Desender et al., 2018, North American Journal of Fisheries Management)
  • “Compared to tickler-chain beam trawlers, pulse trawlers showed relatively higher discard survival under fishing conditions pertinent to these studies.” (van der Reijden et al., 2017, ICES Journal of Marine Science)
  • “These results indicate that, under the laboratory circumstances as adopted in this study, the small-spotted catshark are still able to detect the bioelectrical field of a prey following exposure to [pulsed direct current] used in pulse trawls.” (Desender et al., 2017, Journal of Experimental Marine Biology and Ecology)
  • “These data reveal the absence of irreversible lesions in sole as a direct consequence of exposure to electric pulses administered in the laboratory, while in cod, more research is needed to assess cod’s vulnerability for spinal injuries when exposed to the cramp pulses.” (Soetaert et al., 2016, Fisheries Research)
  • “Electrode diameter and pulse amplitude showed a positive correlation with the intensity of the fish’s reaction. However, the present experiments confirmed that cod also show variable vulnerability, with injury rates ranging from 0% to 70% after (almost) identical exposures near the electrode.” (Soetaert et al., 2016, Marine and Coastal Fisheries)
  • “In conclusion, under the circumstances as adopted in this study, the electrical field seemed to have only limited immediate impact on the exposed animals.” (Desender et al., 2016, Fisheries Research)
  • “Some of the large cod (n = 260) developed haemorrhages and fractures in the spine, and haemal and neural arches in the tail part of the body. The probability of injuries increased with field strength and decreased when frequency was increased from 100 to 180 Hz. None of the small cod (n = 132) were injured and all survived. The field strength at the lateral boundaries of the trawl was too low to inflict injuries in cod.” (de Haan et al., 2016, ICES Journal of Marine Science)
  • “The evidence presented here suggests that the electrified trawls are superior to conventional trawls regarding different aspects, including ecological impact on the North Sea (less bottom impact), management of commercial fishing stocks (less discards) and carbon footprint (reduction of fuel consumption).” (Soetaert et al., 2015, Fish and Fisheries)
  • “The pulse trawls had fewer fish discards […]. The pulse fishing technique resulted in a lower fuel consumption (37-49%), and consequently in spite of lower landings net revenues were higher. A downside of using pulse trawls is the possible spinal damage of marketable cod (Gadus morhua L.), but because total cod landings by beam trawls are low (4-5%), the implication will likely be limited.” (van Marlen et al., 2014, Fisheries Research)

So to summarise:

  • Cod may indeed be affected more severely by pulse trawls than by beam trawls;
  • For other species the effects appear negligible;
  • There are clear benefits in lower fuel use, greenhouse gas emissions, selectivity, and sea floor penetration.

Basically it’s a trade-off between a possible (but possibly limited) damage to cod versus higher fuel use, greenhouse gas emissions, and damage to shellfish and other benthic life. These scientific findings have led ICES to conclude that “pulse trawling has fewer environmental and ecological effects than beam trawls.

The response by BLOOM, the NGO at the forefront of this crusade against pulse trawling, to ICES’s advice? Bloom_FR status 1002253942108061698

Note that all studies I just cited appeared in peer-reviewed scientific journals. Add to this that ICES is more or less to North Atlantic fisheries research what the IPCC is to climate research, and you see the similarities. How often do climate scientists get to hear they’re only in it for the money? How often do pseudosceptics ignore the vast body of scientific evidence that climate change is happening, that much of it is driven by man-made emissions, and that this is a huge problem? Really, there is not much difference between climate deniers (I’m sorry, I mean to say deniers of the vast current scientific consensus that climate change is happening, anthropogenic, and problematic) and the folks at BLOOM.

And these are not the only examples where science and reason loses against emotions, fake news, and conspiracy theories. Australian green NGOs convinced the government to revoke the license of the Margiris trawler, even though CSIRO found its concessions respected ecological limits. Scientists time and again found no detrimental effects of genetic modification, but opponents pay no attention or refer to studies that have been done so poorly they had to be retracted. And don’t get me started on vaccination.

Perhaps we’re not speaking the right language?

This brings me to the second lesson: all too often scientists expect facts to speak for themselves. It may work like that for us (or so we think, wrongfully), but there is a big bad world out there where there is emotion, cherry-picking, motivated reasoning, political cynicism, and other monsters that will tear that illusion to shreds. Whether we like it or not, facts are not enough if we want our research to have the impact it deserves. Scientists, especially natural scientists (but probably also economists), need to learn that explaining your research is not enough: we must also consider how our findings are being used and interpreted in the wider political and societal debate, and we might need to involve different societal actors in the research in a much earlier stage to build trust and to understand the concerns and loyalties that determine people’s support for, or opposition to a policy.

These two, for me, are the main lessons from this sorry saga.

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