Fish Farmer

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.’

 ??  ?? Left: Mowi oceanograp­her Philip Gillibrand; Data
Left: Mowi oceanograp­her Philip Gillibrand; Data
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 ??  ?? Left: Computer modelling has become more sophistica­ted
Left: Computer modelling has become more sophistica­ted
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