Are Scottish salmon farmed in crowded conditions?

No, Scottish salmon are not crammed into seawater pens. In Scotland our salmon are stocked in line with the best scientific research with around just 1.5% fish to 98.5% seawater. This allows for plenty of space for every salmon swim while also allowing for natural shoaling behaviours to occur.

It's worth remembering that the structure you can see on the surface is just the very top of the pen. Salmon pens can be up to 120 metres in circumference and be as deep as 30 metres.

Scottish salmon farmer hand-feeding fish

Sited to harness the natural tides and currents it means that each pen is filled with millions of litres of free-flowing, clean, oxygen-rich seawater.

Scotland has among the lowest aquaculture stocking densities in the world - equating to 15kg to 17.5kg of fish per cubic tonne (1000kg) of seawater. By comparison US and Danish land-based salmon farms stock at a density of around 140kg of fish per cubic tonne.

Can salmon get chlamydia?

In the scale of weird questions we get asked about Scottish salmon farming this has to be among the strangest.

On researching the origin of the question we discovered that the claim is being used by a small number of fringe activists who appear intent on spreading misinformation about our sector.

But, to the question itself - salmon, wild or farmed, can be infected by a chlamydia-like bacterial organism, Piscichlamydia. Veterinary research initially suggested that it may be a cause of gill cysts but that is now thought to be unlikely.

How are farmed Scottish salmon killed?

All fish farmed by Scotland's salmon producers are humanely slaughtered at the point of harvest.

This means that 100% of Scottish salmon are stunned, either percussively or electrically, to render them fully unconscious prior to bleeding.

This is a process carried out by dedicated trained staff, who have access to emergency stunners should they be required. It means that fish can taken from the water, stunned, slaughtered and placed onto ice for transport in a matter of seconds.

What is formalin?

What is formalin?

Formalin is a 37% aqueous (water) solution of formaldehyde and is an authorised medicine. Formaldehyde is the active ingredient that is used to treat some waterborne micro-organisms. Formaldehyde occurs naturally in the environment.

Why is it used?

Like all other livestock sectors, salmon farmers use licensed veterinary medicines and compounds (such as disinfectants) as part of their integrated approach to protecting the health and welfare of their fish.

Why is salmon pink?

The colour of a salmon’s flesh, whether wild or farmed, is determined by its diet. Ranging from orange to ivory-pink, flesh coloration is a result of the levels of organic pigments, known as carotenoids, present in what the fish has eaten.

There are more than 600 naturally occurring carotenoids; they are what make carrots and pumpkins orange, daffodils and sweetcorn yellow and what produces the spectacular colour changes in autumn leaves.

What is emamectin benzoate?

What is it?

Emamectin benzoate is the active ingredient in a veterinary medicine, prescribed to treat sea lice. It is a an avermectin, one of a series of drugs used to treat parasites. Emamectin benzoate is used in agricultural settings to control insects among vegetable crops such as cabbage and broccoli.

Why is it used?

What is Deltamethrin?

What is it?

Deltamethrin is the active ingredient in a veterinary medicine, prescribed to treat sea lice. It is a synthetic pyrethroid which mimics natural chemicals produced in certain chrysanthemum flowers. In agriculture it is used in the control of ticks and is also one of the primary ingredients found in household ant powders.

Why is it used?

What are sea lice?

Sea lice are naturally occurring ectoparasitic copepods which can affect both wild and farmed fish populations. They are tiny, translucent fish parasites and do not affect humans. How planktonic stages of sea lice disperse and find new hosts is still not completely known but sea temperature, light, and currents are all major factors.

What is Azamethiphos?

What is it?

Azamethiphos is the active ingredient in Salmosan, a veterinary medicine prescribed by fish vets to treat sea lice.

Why is is used?

Sea lice are naturally occurring ectoparasites that can cause harm to fish. In order for the Scottish salmon sector to maintain the highest standards of fish health and welfare it is necessary to use medicines alongside a selection of alternative management measures (Figure 1).

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