Consumers asked to challenge supermarkets on the source of Scottish farmed salmon


Salmon & Trout Conservation UK (S&TC UK) is inviting consumers to help identify those supermarkets that are stocking salmon from farms which are failing to control deadly sea lice parasites. 

The inexorable growth of the salmon farming industry in recent years has occurred at considerable environmental cost, particularly the impact of high numbers of sea lice parasites spreading from fish farms to threaten highly vulnerable juvenile Scottish wild salmon and sea trout populations. In many areas, despite the intensive use of aggressive chemicals and other methods to control sea lice on salmon farms, numbers of the parasites are frequently over the industry’s recommended Code of Good Practice threshold for treatment.

Research by leading fisheries charity S&TC UK indicates that there are some 120 salmon farms in Scotland within regions where the industry’s own aggregated sea lice figures exceed the recommended threshold limits. 

Fish farm cages can contain hundreds of thousands of farmed salmon, which, where treatments fail, act as efficient hosts for the sea lice parasite, which then reproduces, releasing huge numbers of mobile juvenile sea lice out into the local marine environment.

Carrying an unnaturally high burden of sea lice is known to compromise severely the survival of juvenile migratory salmonids. Lice feed by grazing on the surface of the fish, eating the mucous and skin. Large numbers of lice soon cause the loss of fins, severe scarring, secondary infections and, in time, death. Quite literally, the fish are eaten alive.

Although background levels of these parasites occur naturally in the sea, juvenile wild salmon and sea trout are not equipped to cope with large infestations. The advent of salmon farming, in largely enclosed sea lochs, has led to a fundamental change in the density and occurrence of sea lice in parts of the coastal waters of the west Highlands and Islands, with gravely negative consequences for juvenile wild salmonids.

Dr Janina Grey, Head of Science with S&TC UK, believes it is time for a positive change: “The long-term goal has to be closed containment, which biologically separates the farmed fish from wild fish and the farms from the wider environment, preventing the spread of sea lice and other diseases. In the meantime, we need to identify and put pressure on those supermarkets, which are selling farmed salmon from areas where sea lice exceed the recommended limits ,and  to be more responsible. We need consumers to be our eyes and ears and take up the challenge to help us make a difference.”

S&TC UK would like consumers to help identify those supermarkets which are selling fresh or smoked salmon grown in those parts of Scotland which are failing to keep sea lice numbers within reasonable limits.

Dr Grey explained: “We are asking consumers, whenever they are in a supermarket, to check out the label on any Scottish salmon packaging. There is no need to purchase the product, just take a picture of the packaging and upload to social media.”

S&TC UK are suggesting that the picture should be accompanied by one of the following captions:

If the salmon has no farm origin listed on the packaging, tag the supermarket and ask them why?

@tesco Which farm does this salmon come from? #salmonfarmreform @SalmonTroutCons

If the salmon comes from one of the farms listed on the S&TC UK website: ( that are in a confirmed high sea lice region, tag the supermarket and ask why they are selling it.

@sainsburys Should you be selling this? #salmonfarmreform @SalmonTroutCons

Dr Grey concluded: “We can all help to ensure that salmon stocked by supermarkets does not originate from the most damaging regions. The supermarkets are failing in their environmental obligations by selling fish from regions of Scotland where sea lice are not being adequately controlled. Consumers have a right to feel confident that any farmed salmon is sourced from a region where sea lice numbers are under reasonable control, thus limiting the threat to wild salmon and sea trout.”

For more advice, please contact Lauren Mattingley at S&TC UK on email:


Picture captions: Carrying an unnaturally high burden of sea lice is known to seriously affect the survival of juvenile migratory wild Atlantic salmon and sea trout populations. Lice feed by grazing on the surface of the fish, eating the mucous and skin. Large numbers of lice soon cause the loss of fins, severe scarring, secondary infections and, in time, death. Quite literally, the fish are eaten alive.

Notes to editors:

For further information on this press release, please contact: Morag Walker, on 07736 124097 or email:

1) Salmon & Trout Conservation UK (S&TC UK) was established as the Salmon & Trout Association (S&TA) in 1903 to address the damage done to our rivers by the polluting effects of the Industrial Revolution. Since then, S&TC UK has worked to protect fisheries, fish stocks and the wider aquatic environment for the public benefit. S&TC UK has charitable status in both England and Scotland (as S&TCS) and its charitable objectives empower it to address all issues affecting fish and the aquatic environment, supported by robust evidence from its scientific network, and to take the widest possible remit in protecting salmonid fish stocks and the aquatic environment upon which they depend.

2) Scottish Government action required
Fisheries scientists – including the Scottish Government’s own scientists - are firm in their conclusions that sea lice produced on fish-farms harm wild salmon and sea trout. Salmon & Trout Conservation Scotland (S&TCS) believes that these threats are not being addressed by effective regulation and control of sea lice numbers on fish-farms in Scotland, which are essential to protect wild fish populations, many already significantly reduced. In 2015, S&TCS raised a formal Petition to the Scottish Parliament, which seeks to change the law, firstly to require immediate culls or harvesting of farmed salmon where sea lice numbers have effectively gone out of control and secondly to give fish farm inspectors the legal duty to control sea lice on fish farms, expressly to protect wild fish populations from juvenile sea lice infestation from marine cage fish farms. The Petition is currently being considered by the Scottish Parliament’s Rural Economy and Connectivity Committee.

3) S&TCS Aquaculture Policy is available from