Fish food for a megafarm

I’ve mentioned a Scottish proposal to raise salmon on the world’s largest onshore (tanked) fish farm. This new megafarm would, I assume, raise Atlantic salmon (Salmo salar) as offshore (caged) farms do.

The plan would be to feed these salmon on pellets made from ‘ragworms, algae and amino acids’. What are those? We know the ragworm (Nereis diversicolor). Wild N. diversicolor is widespread and abundant on the shores of Western Europe. It’s a popular live bait for sea angling. It can also be raised in tanks, although ragworm farming in Britain hasn’t always gone swimmingly. Carnivorous fish such as S. salar might like pellets made of ragworms.

I like the idea of aquaculture moving away from pellets made from wild seafish to more sustainable feeds. There’s research underway in the Netherlands to make ragworm pellets using farmed ragworms. Those Dutch scientists are working with Nereis virens instead of N. diversicolor.

Meanwhile there’s research underway in Nordic countries to make pellets from ‘microalgae, seaweed and mussel meal’. I don’t know much about the microalgae used in the Nordic research but maybe that’s a good idea for a fish food ingredient.

As for amino acids, if the proposed Scottish megafarm would require those, I’d like to know where they’d come from. All proteins are made of amino acids and all organisms are made of a lot of different molecules, including proteins. I’d like to know which organism would be the source of amino acids for the megafarm’s feed pellets. But there’s no obvious reason why that shouldn’t be done sustainably. Perhaps waste from meat or fish processing could be recycled into a fish food ingredient. Perhaps that’s where the mussel meal idea comes in.

For now the salmon megafarm is only a proposal. If I find out that it’s been approved and built, I’ll let you know.

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About argylesock

I wrote a PhD about veterinary parasitology so that's the starting point for this blog. But I'm now branching out into other areas of biology and into popular science writing. I'll write here about science that happens in landscapes, particularly farmland, and about science involving interspecific interactions. Datasets and statistics get my attention. Exactly where this blog will lead? That's a journey that I'm on and I hope you'll come with me.
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8 Responses to Fish food for a megafarm

  1. EqFe says:

    It’s always fascinated me, that by and large, we don’t eat terrestrial carivores, although free range chickens do eat a lot of insects, but many of our favorite fish are carniverous. It certainly has complicated fish farmin, Small freshwater fish farms in the US often stock a high value fish like largemouth bass in a both also stocked with sunfish to give the bass food. I was suprised to read recently that 60 of the seafood consumed in the US was farm raised.
    The termustainability combined with seafood would be a really novel concept. My kids are tire of hearing that the biggest catch I had of this or that speacies was 45-50 years ago. Or the tales of what it called a jumbo shrimp today used to be a medium.

    • argylesock says:

      60% of seafood in your country being farm-reared! That’s amazing.

      The point about eating carnivorous fish is one that, I suspect, vegetarian leaders would like to play down. In my post above I mention the option of using meat waste in fish-food pellets. A fish dinner might not be quite so pure for veggies, then, eh?

      • EqFe says:

        For the longest time, meat wast was fed back to animals raised for meat in this country, I believe that has largely stopped, so it needs to go somewhere, fish farms seems like sensible. use for them.

  2. Finn Holding says:

    I think the amino acids would be synthesised chemically if they are required to be fed individually. But as you point out, amino acids are the constituents of proteins, so I think it’s likely they would be produced from proteolytic digests of proteins produced in bioreactors.

  3. Finn Holding says:

    Chemical synthesis would be more expensive, I think biorectors could probably produce them by the ton fairly cheaply

  4. Pingback: Fishmeal and fish oil in aquaculture | Science on the Land

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