A better way to farm fish | FT Food Revolution

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You certainly get your steps in here the way we've designed the farm now.

Sustainable Blue, a land-based fish farm in Canada's Nova Scotia, produces around 20,000 kilos of whole Atlantic salmon each week, but these fish have never seen the Atlantic. The salmon goes from hatch to harvest in giant tanks indoors.

We have to move the fish, of course. And we want to also keep the fish at a low stress level. And the easiest way to do that with any fish is to keep them in water. You can see over there a sort of a double pipeline running for several thousand feet. And we'll actually pull from one building, push fish up into another building. And for them, it's just a theme park ride. And we have clear sections. We can watch them go by and wave.

Aquaculture, or fish farming, both on land and in pens out at sea is the fastest growing form of food production in the world. Well over half the seafood on the planet is farm raised. Critics and animal rights campaigners have criticised indoor fish farming as being akin to industrialised battery farming. And growing fish indoors like this is still a niche industry.

So these fish are actually feeding now. They're probably two-and-a-half, three-months old. There'll be a batch that came through the egg incubators and are now here just starting their life as a fish, growing up and getting a bit bigger.

The tanks here rely on the technology called recirculating aquaculture systems, or Ras for short. Less than 5 per cent of farmed fish is raised in this way.

It looks like a lot. It is a lot, but we know what it does.

By constantly recycling the water they're using, Ras systems allow fish to stay disease free in a controlled environment without the use of antibiotics or pesticides.

The ocean has threats, temperature swings, violent storms, disease risk, and so on. And when you're farming fish in the ocean then there's no way to protect your fish in an open environment from those kind of threats. So we choose to mitigate that by bringing fish farming into an environment where we can fully control it.

We're also not impacting the ocean in the way that we farm salmon. So we're not discharging waste back into the ocean. We leave the ocean to itself completely.

Leaving the ocean to itself is something that this Nova Scotia based couple is passionate about. They're co-authors, investigative journalists, and spouses. And together, they're holding industrial ocean-based open net pen salmon farming to account.

I'm Doug Frantz, the co-author of Salmon Wars, The Dark Underbelly of our Favourite Fish.

Wow. You could remember that! My name is Catherine Collins.

You're the co-author.

I'm the co-author of Salmon Wars with this guy right here.

We went to a meeting in a village near here called Mahone Bay to talk about the plans by big seafood companies to put in more than 20 open net pen salmon farms along the pristine coast of Nova Scotia. And we came away from that meeting deeply concerned, and that's how we spent the next more than two years investigating the industrialisation of salmon.

People all over the world don't know what they're eating when they go to the store and they buy fresh Atlantic salmon. These salmon are crammed 100,000 or more in a single cage submerged just below the surface, and they're fed a steady diet of wild fish. And they live in their own faeces. They are attacked by a parasite called sea lice.

When you look at the mortality rates, this is one of the things the industry doesn't want you to know. They do die at a rate of 20 to 25 per cent in these farms. I can't imagine any other food industry would accept that sort of mortality rate. Look at chickens and cows at 5 and 3 per cent.

Concerns about open pen fish farms have been growing steadily in recent years. The Canadian Prime Minister Justin Trudeau has pledged to transition away from open net fish farming by 2025, but major farm salmon producers have challenged these plans.

Norway, the world's biggest producer of farmed salmon, is trying to encourage producers away from ocean-based farming by offering free licences to land-based farms while making open net farming more expensive.

Meanwhile, Denmark, southern Argentina, Alaska, California, and Washington State have all banned marine fish farming entirely. For Washington's commissioner of public lands, the ban is a direct consequence of the collapse of a net pen facility holding over 300,000 Atlantic salmon that took place in 2017.

Back on August 19, 2017, there was a complete collapse of one of the net pen facilities, and hundreds of thousands of Atlantic salmon were escaped into the Puget Sound, the Pacific Ocean, where we don't expect Atlantic salmon to be. We are already sitting currently on 16 salmonids within Washington State that are either threatened or endangered. They are struggling to have enough food supply, enough habitat. And now all of a sudden, they have a species that is coming and competing for food. It's also competing for that habitat.

The idea that we're taking a non-native fish from the Atlantic Ocean and putting it 5,000 kilometres away on the Pacific Ocean is mind boggling. It's honestly a context of hubris that we think we can out engineer every part of our environment. So we've taken action, and we have now prohibited any future net pens within our state waterways.

While land-based farming offers a more sustainable alternative to net pen farming...

This device here is just an automated feeding system. We'll programme how much feed we want them to have over a certain time frame, usually 24 hours.

...not every aspect has been ironed out yet.

It used to be that it took 3 kilos of wild fish to raise 1 kilo of salmon. That's the definition of an unsustainable practise. Today, I believe that ratio is down to about 1.5 kilos to 1 kilo of salmon. That's still pretty unsustainable.

I'm really uncomfortable with the idea that we take wild fish out of sustenance fisheries off of places like the west coast of Africa. They do not belong in a salmon farm so that we can eat our fancy salmon in fancy restaurants.

So the feed issue is one challenge that every aquaculture company in the world is going to have to solve. We're taking fish out of the ocean to turn it into an aquaculture diet to feed to our salmon, trout, cod, or whatever it is that we're growing. So we recognise that there's a significant need to solve that problem.

Feeding all this fish requires some out-of-the-box thinking. Just outside Nova Scotia's capital, Halifax, is one start-up doing just that.

Welcome to Oberland Agriscience. I'm going to take you on a quick tour of our black soldier fly farm.

For the past 18 months, Sustainable Blue has been trialling a feed that could make its salmon less reliant on ocean-based food sources, the larvae of black soldier flies.

So there's many tens of thousands in here. They'll get more than twice this size when they're fully grown. People ask me, you're feeding insects to salmon? And when you ask them and you say, well, what do you think salmon are eating in nature?

Well, actually in nature, salmon spend a lot of their time in rivers where they're actually eating insects. People are demanding higher quality foods. That puts tremendous pressure on our food supply system.

Insects are an incredibly good way of producing a lot of protein in a small amount of space. The soldier fly is actually unique in that what we can do with it is we can actually feed it food waste. And so we're turning food waste into a very high-quality protein.

Both the soldier fly project and the land-based salmon farm are backed by Patagonia founder and billionaire environmentalist Yvon Chouinard.

The only thing that's going to work is competing with these salmon farms with a better product. That's why I'm invested in all these different things. And every time we make the right decision for the environment, it leads to more profit. I'm absolutely convinced of that.

But advocates of ocean-based fish farming say that despite some bad players, standards are generally high.

Unfortunately, seafood is a lot like agriculture. It's kind of all over the place. What I can say in general is that the vast majority of seafood, whether it's farm raised or wild caught, is healthy. Aquaculture is still a relatively new industry, and there have certainly been missteps that have been made. But if we're going to feed nine, nine-and-a-half billion people in another 27 years, aquaculture is going to have to be a key part of that.

Recirculatory systems, like the one used at Sustainable Blue, are being deployed across the industry, not just on exclusively land-based fish farms. For Frantz and Collins, though, land-based salmon is the only sustainable option even if it does come at a premium.

It's probably 25 per cent more expensive. And the price will come down because they'll get more market share. This is a disruptive technology, recirculating aquaculture systems, and those technologies take time to work out the bugs. We would like to see all open net pen salmon farms on the ocean disappear.

Move them on to land and raise that salmon on land in properly certified facilities where you have not only certifying the operations and the lack of waste and the sustainability of the feed but also certifying the health of these fish.

Back at Sustainable Blue, David Roberts is inspecting the near fully grown fish.

He's a little bigger. Still not quite market size yet, but it's a nice beauty. This is high school, the final growth stage where they'll attain a marketing weight of around 4 kilos, 8 to 9, 10 lbs range, and then that's next week's harvest that is going out.

A harvest going out into a world where the demand for healthier and more sustainable sources of protein continues to grow and scrutiny about the way our seafood is raised intensifies.