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.

Formaldehyde is used to protect our young salmon from naturally occurring water-bourne micro-organisms such as Saprolegnia during their freshwater stage of life. There are many different species of Saprolegnia and they are found in almost all freshwater environments.

Saprolegnia are fungal-like organisms that can infect fish at all freshwater developmental stages. If left untreated such infections can be serious for the fish and potentially lead to death.  For that reason treatment with formaldehyde is sometimes a vital and necessary part of salmon farming, to ensure fish health and welfare.

How is it administered?

Fish are treated with formaldehyde through what is known as a “bath treatment”.  Formaldehyde is added to the water and fish are “bathed” in a weak solution for a short period of time, after which the treatment is safely flushed away.

For our open net farms in freshwater lochs we create a bath using a tarpaulin to reduce the quantity of water we need to treat and thereby reduce the quantity of medicine we need to use.

How does it affect the environment?

Formaldehyde itself is a naturally occurring compound that swiftly breaks down in water and is therefore safe to use for both fish and the environment.

Is it safe to eat salmon treated with formaldehyde?

YES. This product is only used in our freshwater facilities. Our fish then have many months, typically at least 18 months at sea where they are reared prior to harvesting for the food chain. This time at sea means that no formaldehyde residues are present in our fish when they are harvested for food consumption.

Even if fish were to be consumed at the freshwater stage they would still be safe to eat as formalin has a very short 'withdrawal period' of less than a day.

What is a 'withdrawal period'?

A withdrawal period is the minimum time before harvest during which treatment with a veterinary medicine must cease to ensure that any residues of veterinary medicines in the edible parts of the aquaculture product are within the limits established for the safety of consumers.

How is its use controlled?

The use of any medicines, disinfectants and other compounds are strictly controlled by several regulatory authorities. Products are produced and distributed through a safe and fully traceable supply chain. Compounds used on fish farms are heavily and strictly regulated.

The use of formaldehyde-based compounds is controlled by four main bodies - the Veterinary Medicine Directorate (VMD), Food Standards Sctoland (FSS), Scottish Environmental Protection Agency (SEPA) and Health & Safety Executive (HSE).

Where can I find out more?

You can find out more about formaldehyde and its everyday uses in everything from healthcare products to furniture production by clicking here.

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).

How do acoustic deterrent devices work?

The first acoustic deterrent devices (ADDs) were developed several decades ago, and were basic, if imaginative: farmers used underwater speakers to play recordings of killer whales (orcas), a natural predator of seals. However, the latter quickly caught on and the deterrent effect was short-lived.

Modern ADDs use underwater transducers (a device that turns one form of energy into another – in this case, electrical energy into sound). The deterrent, which creates a temporary sonic fence around a salmon farm can work in two ways:

Salmon mortality: what are the causes?

Fish health and welfare are at the heart of successful Scottish salmon farming. It is in everyone’s interests to operate to the highest of welfare standards.

The reproductive strategy of fish is to produce a large number of offspring so that a proportion will survive to adulthood. 

Fish, including farmed fish, are subject to a number of pressures in the environment, particularly naturally present pathogens. It can, therefore, be expected that some fish will experience challenges to their health. 

Why is hydrogen peroxide used by salmon farmers

What is hydrogen peroxide?

Hydrogen peroxide is water with an extra oxygen molecule. It is a naturally occurring substance found in the atmosphere, soil and water, and is naturally produced by many living organisms including humans in breast milk. It also has many commercial applications including, sterilisation of juice and milk cartons, hair and teeth bleaching and as a disinfectant for contact lenses.

Why is hydrogen peroxide used in salmon farming?

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