Animal welfare is vital to us at Sainsbury’s – and that applies as much in water as it does on land. That’s why all our farmed salmon is RSPCA Assured.

But we’re also looking for sustainable ways to make salmon healthier. So, we’re helping our Scottish salmon farm suppliers to get rid of the minute crustaceans that cling on to salmon, with the help of ‘cleaner fish’, or wrasse.

The oval-shaped crustaceans that hone in on farmed salmon occur naturally but are a problem for fish farmers, as they can damage stocks.

There is also a risk that the pests could be passed on to wild salmon and that the medicines currently used to offset them could harm the environment.

However, wrasse eat these marine pests. So we hope that, by adding them to salmon farms, our suppliers will be able to protect their fish with less use of medicines – and so help the environment.

We believe this could become standard practice for fish farmers in future, and mean more sustainable salmon in our stores.

Trawling the world of wrasse

We’ve partnered with the University of Stirling, and our Scottish supplier Marine Harvest, to understand more about these cleaner fish.

They are collecting data on how wrasse behave and developing special fish feed to keep them healthy, so that they can keep salmon well in turn.

They are also trialling the use of artificial light during the winter months, to see if that improves the health and survival of fish.