Call to ban fish farm use of formaldehyde in lochs

Pressure is growing on the Scottish Government to halt the use of formaldehyde on West Highland fresh water lochs, including three in Lochaber - Loch Shiel, Loch Lochy and Loch Arkaig.

Campaigners for Inside Scottish Salmon Feedlots (ISSF) have called for a total ban on the chemical at fish farms until a ‘proper’ public consultation on its use has taken place.

It follows a Freedom of Information request earlier this year to the Scottish Environment Protection Agency (SEPA), which revealed more than 22 tonnes of formaldehyde had been poured into cages at 12 fish farms across Scotland between April and December 2019.

Fish farming companies are officially sanctioned by SEPA to apply the chemical to water as it is used to treat farmed salmon and control fungus, parasites, and disease.

The practice is legally permitted at a number of lochs, including Loch Shiel at

Glenfinnan; Loch Lochy and Loch Arkaig, both near Spean Bridge; and Loch Tralaig near Melfort, south of Oban.

Campaigners have raised concerns about the impact on human health and wildlife, and ‘accidental overdoses’ where more of the chemical enters the water than allowed.

The ISSF has now raised the issue with Roseanna Cunningham MSP, cabinet secretary for the environment, and Gillian Martin, convenor for Holyrood’s Environment, Climate Change and Land Reform Committee.

The ISSF opposes the use of formaldehyde, calling it a ‘cancer causing’ chemical used for embalming.

The Scottish Government said in a statement: ‘The use of formaldehyde is strictly regulated by the independent Scottish Environment Protection Agency (SEPA), and it can be safely used in fish farming. Formaldehyde use in fish farming, as regulated, does not pose a risk to food safety.’

Corin Smith, founder of ISSF, based in Perthshire, said it recognised formaldehyde had been used in farming for many years and that it broke down ‘relatively rapidly’ in water. The concern is the quantities being used, and accidental overdoses and their impact.

Mr Smith said: ‘Having reviewed existing literature it is not clear or well understood to what extent formaldehyde on freshwater fish farms will directly impact wild fish, of any species, at the alevin, fry or parr stages, or indeed aquatic invertebrates and other foundation organisms that are in proximity to freshwater fish farms.’

The Scottish Salmon Producers’ Organisation (SSPO) declined to comment on the specific claims by ISSF.

It said formalin was ‘fully approved for use by SEPA’ and added: ‘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.’

The concern is quantities being used and accidental overdoses