Mowi Mapping the seabed
Mowi deploys oceanographers to help maximise production
NEW state-of-the-art technologies might be the first thing salmon farmers reach for when tackling sea lice and other environmental challenges, but the less evident investment in human capital is proving to be the smartest response. Two and a half years ago, Mowi Scotland made this investment by hiring oceanographer Philip Gillibrand and his team of oceanography data analysts and modellers.
Gillibrand has brought his expertise in computer modelling to map the best sites to farm in and to approach the problem of sea lice from a different perspective.
By exploiting the most advanced modelling technology – and also creating his own – Gillibrand hopes this will allow the company to treat for sea lice, and other health issues, more efficaciously and farm as sustainably as possible.
At the heart of these endeavours is the new DEPOMOD modelling system launched by Sepa (the Scottish Environment Protection Agency) in 2017.
Hailed as a breakthrough for farmers, its far greater levels of accuracy have enabled flexibility in the 2,500-tonne biomass cap. But producers applying to farm more fish must show they can do so sustainably.
The DEPOMOD model can help do this, said Gillibrand, but first farmers need to understand how the system actually works.
‘It’s far more sophisticated than the old model, which is both a strength and a difficulty – it’s taken us two years to get to grips with it and I’ve been using coastal ocean models for two decades.
‘The model needs more specialised skills and knowledge, which companies didn’t have, though I think they are getting it now and recruiting more experienced modellers.’
NewDEPOMOD was developed by SAMS
(the Scottish Association for Marine Science), where Gillibrand worked before a spell at UHI (University of the Highlands and Islands) in Thurso, Caithness. As a hands on user since its introduction, he said: ‘I think we probably know as much about it as anybody.’
Gillibrand has a team of four and they make measurements of currents and waves, analysing the data to try to understand the environmental impact. Other colleagues undertake seabed surveys, which are analysed for benthic quality, around the sites. The new model allows companies to farm both larger sites and in more exposed areas.
‘Sepa put a lot of effort in setting it up to run in a very generalised way so anybody can run it, but you get very conservative and precautionary results that way,’ said Gillibrand.
His team has been learning how to calibrate the model against the data they collect to get more realistic predictions of what’s sustainable at every site, with the aim of maximising production. The results tend to be very site specific, he said.
‘Some sites we’re finding we can’t increase biomass so we’re looking at sites at more exposed locations offshore, where the dispersion of waste is better.
‘Recently, we’ve been collecting more data, partly because Sepa requires that but partly to help calibrate this model. The more data we have, the better and more accurate the predictions.’
They base predictions on existing cycles and run a forecast about how much more biomass they can farm, while still complying with regulations so that the farm remains sustainable.
What are they measuring now that they may not have measured in the past?
‘We’re still measuring the same seabed measurements but just more of them,’ said Gillibrand. ‘We measure currents for longer – we
used to have to measure for 15 days, now it’s 90 days at every site. That’s a Sepa regulation.’
He said his former partner in the team, Ewan Gillespie, who is now retired, ‘was very quick to sense the way things were going’.
‘He set up the 90-day collection programme, and the extended sediment surveys, before they were really necessary.’
Last year, Mowi announced it was offering to relocate two of its inshore farms, Loch Ewe and Loch Duich, to higher energy sites.
‘We are trying to shift our operations out into more exposed locations, away from wild fish populations,’ said Gillibrand.
He is looking at how the sites are all connected in terms of sea lice and disease, and has developed his own sea lice dispersal model. And he is involved in an ongoing SAMS project, outlined at the EAS conference in Berlin last October.
‘The industry has talked for a long time about moving offshore and how beneficial it would be, but no one has done any actual assessment of that. So this project, Off-Aqua, led by SAMS, was to look at a sheltered site, an intermediate site and an exposed one.’
It will examine sea lice dispersion at these sites, and investigate the health impacts on the fish, and the sea lice connectivity, just to see whether there is any difference or any benefits to moving offshore, said Gillibrand.
He used to work for what is now Marine Scotland Science, doing the modelling they were putting together in the 90s, looking at the impacts of fish farming.
Asked if he could now draw any conclusions, based on his experience, about the impact of salmon farms and whether sites should be moved offshore, he was cautious.
‘I don’t think it’s as simple as the whole industry has to move offshore, but I do think we have to farm the right biomass at the right location.
‘So if there is poor exchange, then the biomass will be smaller – there is no getting away from that. But if you want larger farms but fewer of them, then we would have to move further offshore.’
He believes that Mowi’s smaller inshore farms can be managed sustainably too, if the biomass is matched to the location.
‘We have regulations that apply to every site and we have to meet the stipulations that Sepa enforce in terms of sustainability.
‘If you don’t over farm, then the seabed will remain in a relatively healthy enough state if you took the farm away. I certainly don’t think there is any permanent damage.
‘Sepa did a large survey of Shetland last year and at a couple of sites where there hadn’t been a farm for several months, they couldn’t find any impact.
‘The sea is a very dynamic place and I think most of what we’re putting in is organic carbon and it quite quickly assimilates and is dispersed.
‘We do discharge quite a lot of organic carbon in limited areas, so temporarily there is an impact, without a doubt, but if you took a farm away, that carbon would soon disappear. But I do think we need the right biomass in the right places.’
He said that medicines, too, break down, so long as they are not over used. He and his team are currently developing computer models to calculate the amounts of medicine that can be used to treat for things like sea lice effectively, without detrimental effects.
‘A lot of our consents are being constrained by Sepa on what we think is a rather flawed basis – we don’t think we have efficacious treatments; we have to treat such small amounts on a daily basis so by the time you’ve treated a farm, the sea lice are back where you started.
‘There are two [sea lice medicines], emamectin benzoate (which is
Slice) and azamethiphos (Salmosan) bath treatment, which we’re also allowed in very small amounts – in many cases you can only treat a cage a day.
‘So if you’ve got 12 cages, then it takes 12 days to treat, and by the time
“The sea is a very dynamic place and most of what we’re putting in quickly assimilates and is dispersed”
you’ve finished the last one, the lice are back at the first one.
‘I think that’s very conservative – it doesn’t look at dispersion in any kind of realistic way in the sea. I’m developing a model that looks at dispersion and dilution of these treatments in a much more realistic way, as it happens in the marine environment.
‘That allows us to use more [medicines] on a daily basis while still meeting the same EQS (environmental quality standards).’
Mowi has recently successfully managed to increase biomass up to 3,500 tonnes at some exposed open sea sites by using advanced modelling that demonstrates that a higher biomass can be farmed safely within environmental standards.
Further applications are also in various stages of development. Gillibrand said he has not been involved in any cases at Mowi where they are looking to increase biomass at inshore locations a long way up sea lochs.
He thinks there will be a gradual move away from farms far up sea lochs, but it depends on getting other licences to farm elsewhere.
‘We’re looking at ones that are at the entrances to sea lochs or out in the coastal zone – and around islands.’
He said he finds the modelling team at Sepa, some of whom he has known for a long time, ‘very reasonable and good to deal with’.
He also said Mowi is working much more closely with some of the fishery boards and trusts now, putting in agreed environmental management plans for new sites. Modelling sea lice connectivity also has a role to play here, helping to quantify the risk to wild fish and helping inform appropriate monitoring locations.
But he acknowledged that the debate about the impact of sea lice on river systems was ‘a contentious area’.
‘Sea lice are quite long lived, they can live up to 15 days or so, and they can travel quite a long way as larvae when they’re released by the females. But if you’re away from areas where they can concentrate, like sea lochs, I can only think that’s a good thing, away from river mouths where wild fish are migrating.
‘It’s still an active area of research but intuitively it seems only sensible to move away from rivers.’
However, the shift to high energy sites requires huge investment in infrastructure, and therefore a massive commitment from the salmon companies.
‘To start a new site there is a large infrastructure investment, so the biomass that we start with has to recognise that and that’s a challenge at the moment because Sepa’s approach is to start small and build up,’ said Gillibrand.
‘They would prefer us to start at a smaller biomass and build incrementally by demonstrating environmental sustainability. But starting with a 1,000 tonne farm off Rum, for example, just wouldn’t justify the costs.’
Mowi Scotland boss Ben Hadfield has said that moving ‘offshore’ is a step by step approach, moving to more, higher energy sites near islands rather than actually offshore, and then maybe gradually moving further offshore once the technology has been tested.
Gillibrand said they were not looking at ‘enormous farms that are self-contained with people living on them, like Ocean Farm [operated by SalMar in Norway]’.
‘I don’t think there are plans for anything like that in Scotland yet. We’re looking at high energy sites but still quite close to land. The environmental data sets we are collecting are also helping to ensure our equipment meets the design requirements of the Scottish Technical Standard at these locations.’
Site selection is still focused on the west coast and the Western Isles and Gillibrand said Mowi is continuously collecting data at potential sites.
Studying the seabed as meticulously as he does, Gillibrand is perhaps better qualified than anyone to make predictions about salmon farming’s long term future. Is there room in the ocean for a lot more fish farms?
‘I think so. If you look at the carbon footprint of aquaculture it’s very low compared to other sources of animal protein.
‘Compared to beef and dairy and other forms of livestock agriculture, it’s a very sustainable, climate friendly form of providing people with protein.
‘The sea used to be full of fish – we’ve got them penned in but I don’t think any of those organic carbon impacts are any different than they used to be, they are just a bit more concentrated while the farms are in place.
‘We see comparisons [of waste] with sewage from towns but that’s a crazy argument and not supported by science.
‘Due to the constituents of human waste it requires significant levels of treatment to make it safe to release into the sea. Waste from fish farms is very different in nature and content, being mainly organic particulates which are inherently harmless by-products of farming.
‘The industry is trying to improve what we’re doing, improve the models we’re using and understand better the environmental impact we’re having, and therefore we can contain it and farm in the right locations.
‘And with other companies now recruiting people with modelling backgrounds, I think we are moving in the right direction as an industry.’