A leading supermarket chain is being forced to change its labelling after incorrectly stating the origins of Scottish salmon.

The Salmon and Trout Association Scotland (S&TAS) filed a complaint to both the Advertising Standards Authority and Trading Standards against Sainsbury's over its Taste the Difference Scottish farmed salmon.

According to the association, salmon bought in January and April 2013 stated the fish "are reared in sheltered, fast-flowing seawater locations around the Isles of Skye, Lewis and Uist".

But the S&TAS says the individual farms specified on the packaging are all located in rather less fast-flowing locations in Loch Fyne in Argyll, on the mainland.

It says Sainsbury's website also identified the supplier of the salmon as Marine Harvest, when the farms listed are owned and operated by The Scottish Salmon Company. The association also takes issue with the packaging stating the salmon was "responsibly sourced" while there was no explanation of that meant.

Guy Linley-Adams, solicitor to the S&TA Aquaculture Campaign, said: "It is time for the supermarkets to take responsibility for what they are selling and how they market it."

He said sea-lice numbers in excess of industry thresholds, pollution with sea-lice treatment chemicals in excess of Environmental Quality Standards, escapes of farmed fish, unsatisfactory organic pollution of the seabed with food and faeces and farmed salmonid diseases had all been recorded in Loch Fyne.

A Sainsbury's spokesman said: "We are very proud of our record on responsible sourcing of fish. Unfortunately, there has been an error in the information on the packaging of some our Taste the Difference salmon products in recent months. We are now resolving this and sincerely apologise to customers."