Lewis Bennet, Cleaner Fish Manager, Loch Duart

Blog: Trialling a natural habitat for happier, healthier cleaner fish


Fish welfare lies at the heart of everything we do at Loch Duart, with our team providing dedicated care at each stage of life for our salmon to ensure they grow to be the fittest and healthiest fish they can be. This commitment to a lifetime of care extends beyond our salmon, to our stock of cleaner fish which swim alongside the salmon helping to keep them clean and parasite free.

Deploying sustainably sourced ballan wrasse and lump fish – two species native to Scottish waters – is a tried and tested non-medicinal approach to sea lice control, and one which we’ve used for many years at Loch Duart. It is a mutually beneficial partnership, with the wrasse and lumpfish getting to graze on any sea lice which may settle on salmon stock from surrounding waters and our salmon continuing to enjoy a healthy environment.

It’s important to us though that we continually strive to improve the level of care offered to all our fish. Over the years, we have explored new ways of improving the environment for our cleaner fish, including installing artificial kelp hides in our salmon pens, designed to imitate the natural environment our salmon and cleaner fish would experience in the wild. More than an aesthetic improvement, these hides offer the cleaner fish a place to rest up and hide away from other fish when they want to, just as they would in the wild.

Seeking natural solutions wherever possible in our fish husbandry, we are very excited to be working on a new 18-month research project alongside KelpRing, the Sustainable Aquaculture Innovation Centre and the University of Stirling’s Institute of Aquaculture, to test out an all-natural kelp hide solution which has the potential to replace these artificial hides.

A mix of naturally seeded and lab-grown kelp, the ‘KelpRings’ could help us provide as natural environment as possible to that which our ballan wrasse and lumpfish would experience in the wild. Early trials from KelpRing – based just across The Minch from us at the Isle of Skye – have shown that cleaner fish much prefer the natural hide material, compared to artificial hides. Using natural kelp hides brings additional benefits: as well as helping to re-oxygenate and clean the water, they are much easier to maintain than artificial hides and will also help us to reduce the amount of plastic material we use as a business.

We believe that happier, healthier cleaner fish will in turn be even better at helping keep our salmon fit and healthy, and we look forward to learning how our cleaner fish react to this trial.

“The use of cleaner fish, in my view, is the biggest innovation at Loch Duart. They play a vital and valuable role in the business, where they contribute to the fish health strategy. They are also a form of multitrophic farming incorporated into our salmon operations, where they keep our salmon free of sea lice, and we work to meet all of their requirements.”

“Being able to express their natural grazing behaviour requires a range of factors to be met, such as having a habitat or structure in close proximity. We currently use artificial kelp for this, but being able to provide our wrasse with a more appropriate habitat should create a happier fish population and would reduce the need for artificial products. I am very keen to see the results on fish behaviour but also the operational benefits of a habitat that doesn’t need cleaning or regular removal from the pen. As we have seen at Loch Duart across a range of factors, a natural option is always superior.”

– Lewis Bennett, Cleaner Fish manager at Loch Duart