They are tiny little helpers seen as a natural solution to a pesky fish farm problem, but are notoriously tricky to keep happy.

Cleaner fish like ballan wrasse and lumpfish help control sea lice by plucking the pests off the salmon without damaging the fish.

But their complex behaviour traits have posed a challenge to the industry, and cleaner fish mortality is high.

While there is also concern over wild wrasse stocks, which it’s feared have been seriously depleted to meet demand from fish farm operators.

Now, however, an apparently simple solution using kelp could improve conditions for cleaner fish and create a string on knock-on benefits.

Farms often use artificial reefs made from ribbons of black plastic to recreate the cleaner fish’s preferred natural habitat, which raises additional environmental concerns over microplastics in the sea.

Instead, KelpRing uses natural kelp, and is designed to be as close as possible to the type of environment ballan wrasse and lumpfish would experience in the wild.

Early studies have shown introducing natural kelp on salmon farms can have medicinal properties and a calming effect on cleaner fish, boosting their ability to treat sea lice.

Its use raises the prospect of major changes to a sector often under fire for using pharmaceuticals to tackle sea lice, and for the distress the parasites cause to fish.

While the use of natural kelp may also help cleaner fish survive longer and in better health which, in turn, could also address concerns that commercial demand for cleaner fish has led to over-fishing of wild stocks.

The company behind KelpRing has now received a £125,000 funding package from the Seafood Innovation Fund (SIF) to explore the potential benefits natural kelp hides.

The new research will see its KelpRings – also the name of the company’s kelp system – deployed at one of Loch Duart’s salmon farms for the next 18 months.

Institute of Aquaculture researchers will evaluate its impact against current standard conditions, assessing the preference of cleaner fish and mapping behavioural and physiological changes in the cleaner fish population related to their welfare.

They will also look at cleaner fish efficiency by means of sea lice counts and the health and welfare state of salmon.

The research is being supported by the SIF programme, with additional input from the Sustainable Aquaculture Innovation Centre (SAIC), salmon producer Loch Duart, and the University of Stirling’s Institute of Aquaculture.

Martin Welch, founder of KelpRing, said: “Cleaner fish are naturally drawn to seaweed forests and by adding kelp hides to salmon pens, it allows the fish to act as they would in the wild, in their natural habitat.

“Wrasse and lumpfish can live a long and healthy life of up to 25 years if the conditions are right, and measures to enhance their wellbeing can only support their ability to treat sea lice.”

He added: “The KelpRing is a lightweight system which can be deployed in various sizes from one to nine meters in diameter, using a mix of naturally seeded and lab-grown kelp. So far, the aquaculture sector has been incredibly positive about the prospects of using the system and we’re hopeful that the results from this latest trial will prove our hypothesis, with the kelp having a positive impact on Loch Duart’s cleaner fish population and a reduction in sea lice numbers.”

Sarah Riddle, director of innovation & engagement at SAIC, said: “Fish health and wellbeing is one of the top priorities for the sector as it continues to target sustainable growth. Tools that mimic natural habitats are known to improve the health, welfare, and productivity of cleaner fish. For that reason, it is great to see techniques being trialed to bring the environment of salmon farms closer to what would be found in the wild.

“Aquaculture’s focus on cleaner fish continues to gain momentum, with valuable research developments helping to transform the wider approach to sea lice management. Ballan wrasse and lumpfish are crucial to future-proofing the sector, with collaborative research continuing to find new ways of helping them to thrive.”

Lewis Bennett, cleaner fish manager at Loch Duart Ltd, added: “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 behavior 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 behavior 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.”