Alternative fish farming: good for the fish and environment?

DW (English)

Conventional salmon farms have come under fire because of high mortality rates of salmon in aqua culture. In Norway, which supplies over 50% of global production, a farm has taken a more responsible approach.

Transcript

00:00The fjords of Norway, a popular tourist destination and now home to a new kind of salmon farm

00:08committed to doing things differently.

00:10The country supplies over half of global production.

00:14Tomas Myrholt is CEO of Akva Future, which operates the farm.

00:19Whenever he can, he leaves his office to head out along the fjord to be with his team.

00:25Definitely, we're trying to find a new way of doing salmon farming.

00:30Our goal is to reach the utopia of having the world's most sustainable salmon farming.

00:38We believe in working proactively to mitigate the problems before they become problems,

00:44like sea lice for instance.

00:45So we don't have any sea lice here, and also with pathogens and protecting the fish.

00:53Sea lice are a major problem for conventional farms, especially sea lice, tiny crustaceans

00:58that can even cause mass die-offs among their hosts.

01:01And they can also be transmitted to wild Atlantic salmon, whose stocks have plummeted by more

01:06than 50% since the 1980s.

01:09Environmentalists say it's a major problem.

01:13Sea lice is a very bad thing for the salmon in the pens, but also it's a problem for the

01:21wild salmon.

01:23And the wild salmon in this area is the Atlantic salmon, and now it's threatened.

01:28And the decrease in numbers are very dramatic.

01:35Another issue is that the farmed fish often escape through gaps in the nets.

01:39If they then mate with the wild Atlantic salmon, their offspring struggle to survive, leading

01:44to a further decline in the ocean-going population.

01:49And excrement from the aquaculture facility often pollutes the surrounding waters.

01:55That in turn promotes the spread of skin diseases in the fish.

01:59So what makes this farm different?

02:01The key lies in its construction.

02:05Instead of being surrounded by nets, the fish pens are enveloped in plastic.

02:10We have a protective bowl, a closed bag that the fish is in, and we fill that bag with

02:16water from the depth, so it's fresh water from the depth without sea lice.

02:22The aquaculture pens are made of an impermeable plastic outer skin, or bag, and a net to prevent

02:29the farmed fish from escaping and endangering the wild Atlantic salmon.

02:36That double barrier also keeps lice and other parasites out of the pen.

02:46The pens get a fresh supply of water piped in from the cold depths of the ocean where

02:50there are no sea lice.

02:56Excrement from the fish is collected by a filter under each pen and then pumped to the

03:01surface.

03:03It's dried and then used by biogas plants to generate green electricity, or by farmers

03:10as fertilizer.

03:12We're the only salmon farmer that I know that don't have sea lice.

03:16And when the fish gets to just thrive inside of a good environment, you have very good

03:22growth, you have very low mortality, and very good quality of the fish that you harvest.

03:31In 2023, the average farmed salmon mortality rate across Norway was 17%, with infectious

03:38diseases a major factor.

03:40Here the rate is just 4% thanks to a very low level of disease transmission.

03:47The boss shows us the filter systems that are installed under the pens.

03:51In the assembly hall, pump units are being built, which will then be welded together.

03:59The company has a patent on the high-tech filters.

04:02This is the outlet, so this actually regulates how everything is floating in the ocean.

04:07And it's also where we collect the sludge, and if we have any dead fish, we can collect

04:13it here, take it ashore, and use it for another value streams.

04:20Aqua Future says it's making a profit, and that its salmon is no more expensive than

04:25what's sold by conventional producers.

04:30Repurposing the filtered sludge also helps in keeping costs down.

04:37For now at least, the salmon industry is skeptical of the innovative young CEO.

04:47Will his approach bring a lasting, sustainable change to salmon farming?

04:52Thomas Mierholt is optimistic, and is already hatching plans for an expansion.

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