Shellfish Going Dutch
Focus on bivalves as a solution to climate change
ONCE more to Neeltje Jans, the manmade island in the mouth of the Oosterschelde, built as a first stage in the construction of the storm surge barrier. This has been the site of a biennial shellfish conference for some years. There was some confusion this year in that, since it has been held on alternate years in the past, attendees were assuming they met there in 2018 whereas, in fact, it was last held three years ago.
Jaap Holstein had been persuaded out of retirement (from running the Dutch mussel producers’ organisation) to help newly retired Professor Aad Smaal to organise this and they had made an excellent job of it, with a packed programme.
The theme was ‘opportunities and innovations’ and the conference was roughly divided over the two days under these headings, with the first day concentrating on opportunities.
Jaap welcomed everyone to the largest theatre in the visitor centre, big enough to accommodate some 250 delegates, 50 of whom came from outside the Netherlands, representing nine different countries.
While the theme was opportunities and innovations, the arguments in favour of bivalve aquaculture as a solution to our current climate crisis kept breaking through.
And once again, as at the ASSG shellfish conference, I found myself wondering how we were going to get this information more widely known and understood.
Dr Nanou Beekman, a senior civil servant and the director of fisheries at the Ministry of Agriculture, Nature and Food, opened the proceedings and then stayed all morning as chair for the first session.
The first speaker, Wouter van Zandbrink, posed the question as to what the position or role of shellfish production in a circular economy is. He was talking in terms of carbon footprints and said that 35 per cent of the global footprint is due to food production.
He cited two major reports, one from the UN1 and one from the EU2, which provided some evidence that the benefits of shellfish are being more widely appreciated and understood.
The arguments for feeding lower in the food chain are inarguable and, of course, shellfish come out well in this, but he then asked why, if farmers get funded for farming in ways to help the environment, shellfish farmers cannot be eligible for such help.
There are, however, clearly problems within the main growing areas in the Netherlands, as he reported, with mussels diminishing in size as rivers running into the Oosterschelde are being blocked off, and both total production and the size of the mussels is dropping.
“
Holmyard drew the short straw when she was asked to explain Brexit to a European audience”
Also, I learnt from the audience that 40 per cent of the mussels in the Oosterschelde have died and it seems to be due to the ‘cancer’ affecting mussels in France.
The next speaker, Marnix Poelman from Wageningen Marine Research (WMR), also argued for eating at the lowest trophic levels. He quoted a recent paper (Hilborn et al 2018) where arguments in favour of bivalves are very clearly expressed.
He also pointed out that in life cycle assessments (LCA), in terms of greenhouse gases, shellfish farming was placed very favourably.
He went further, however, and reported that there were relatively few studies on energy consumption as part of such studies. One graph, of a LCA4 of bouchot mussel culture, showed that fuel use made quite a significant contribution to outgoings that was hardly compensated for by the benefits of the carbon sink effect. So there is certainly no room for complacency.
This topic was taken up by Henrice Jansen, also of WMR, under the heading ‘climate proof culture – shellfish as carbon and nitrogen sink’.
Henrice explained carefully how there were different methods to calculate how much carbon is sequestered in shellfish culture, but whatever method was used, the punchline was that while the Dutch mussel production could capture more than 4,000 tonnes of carbon per year (using the most favourable calculation method) it would need 1.1ha of mussel bottom culture to mitigate the effects of one car’s use (assuming 13,000km/year and 930 litres of petrol)!
Some of the talks were not as positive as the terms ‘opportunities and innovation’ might imply. Camille Saurel of the Danish Research Centre (DRC) certainly had an innovation to talk about, but in response to what was a severe problem – that of how to deal with extraordinary populations of starfish in the Limfjord.
The photographs showing the degree of infestation were hardly believable but the DRC team of researchers had found ways to harvest these predators from the mussel beds they were destroying, and had set up meal manufacture from them.
They are now producing starfish meal with up to 70 per cent protein, and with better amino acid content than plant alternatives, which can provide a cheaper source of high quality marine protein for the pig and poultry industry.
One problem that remains is how to remove starfish from newly relayed mussel beds, but they are hopeful that the use of ‘mops’ rather than the beam trawl used elsewhere will be successful.
Talks from Ireland (Nicholas Chopin) and France (Jean Prou) showed the scale of shellfish culture in these two countries and elucidated some of the problems they are experiencing.
Meanwhile, two talks on the offshore culture of mussels could have been headed ‘So you think you have problems…’
The first of these was from Antonio Cunha (of
Testa and Cunha, Portugal). While his farm off the south coast of Portugal appeared to be somewhat less ‘offshore’ than John Holmyard’s (Offshore Shellfish, UK) farm in Devon, this clearly did not mean it had less exposure to severe storms. The photos of the resultant disarray were certainly a deterrent to anyone thinking that going offshore might be easy.
There were three talks tackling shellfish trade, but Nicki Holmyard drew the short straw when she was asked to explain Brexit to a European audience.
The speaker ahead of her (Pierre Boels) had nicely set the scene because when talking of his work to establish a seafood hub in Prague, and how it supplied all Europe, he left out the UK as simply ‘too difficult’!
Nicki nonetheless made a very good presentation, setting the scene, reliving the conflicting feelings engendered by the whole process in the UK, and presenting a rather daunting picture of what may well be necessary for the shellfish trade once Brexit is fully realised.
As part of the conference, an award is made for sustainability, announced after the talks on the first day, while wine and most excellent native oysters (supplied by Osterij) are served.
One slight snag is that by this time the simultaneous translators are off duty, so any non-Dutch speaker has no idea what is going on while the shortlisted candidates are interviewed!
The award was won this year by Machienfabriek Bakker, Yerseke, and collected by Wim Bakker, for the development of a more sustainable sock for suspended mussel culture.
The runners-up were Van Es Verpakking, Yerseke (Willem Bakker), World of Oysters, Yerseke (Jean Dhooge), and Franken Machines en VAM Watertech, Borssele (Hans Blaak).
1Costello, C., L. Cao, S.Gelcich et al 2019 The future of food from the sea. Washington, DC: World resources Institute. Available online at www.oceanpanel.org/future-food-sea
2Food from the Oceans- How can more food and biomass be obtained from the oceans in a way that does not deprive future generations of their benefits? European Commission
Directorate General for Research and Innovation
3Hilborn, R., Banobi, J., Hall, S. J., Pucylowski, T., & Walsworth, T. E. (2018, August 1). The environmental cost of animal source foods. Frontiers in Ecology and the Environment. Wiley Blackwell. https://doi.org/10.1002/fee.1822
4Aubin, J., Fontaine, C., Callier, M., & Roque d’orbcastel, E. (2018). Blue mussel (Mytilus edulis) bouchot culture in Mont-St Michel Bay: potential mitigation effects on climate change and eutrophication. The international journal of life cycle assessment, 23, 1030-1041. doi: 10.1007/s11367-017-1403-y