Getting to grips on the sea lice menace

Sea lice are a bit like fleas – a fact of life, but not something most people want to talk about. Salmon farmers have no choice. Sea lice are a naturally occurring parasite with the power to wipe out their livelihoods.

Sea lice are ectoparasites that attach to a salmon’s skin. They feed off its mucus and blood and breed rapidly. Currently, there are about nine different treatments being used with varying degrees of success to control the problem.

These include active interventions such as mechanical brushing, the use of chemical solutions and optical delousing and preventative measures such as lice skirts and putting so-called “cleaner” fish into the pens to eat the parasites.

However, concerns have been raised about the impact of some of the treatments on fish welfare and the environment and none of the existing methods work 100 per cent.

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Determined to change this is Castlebar-based engineer, Rory Casey, who has developed an environmentally and fish friendly solution that uses photonics (light) to kill the lice without harming the salmon. Based on the scientific evidence gathered to date, Casey believes his technology has the potential to solve the problem once and for all.

Casey’s background is in the design and manufacture of fibre optic cables and his speciality is photonics. He first became aware of the devastating impact of sea lice through a fish farming friend who threw down the gauntlet to Casey to solve the problem. Never a man to refuse a challenge he started thinking about a possible solution straight away.

By the time he had driven from Killary Harbour to Castlebar (about an hour and a half), he already had the bones of a plan. "I went straight to the office and wrote it down and I have not deviated from it since," says Casey who set up Atlantic Photonic Solutions (APS) towards the end of 2018 to commercialise his invention.

"The salmon farming market is worth around €14 billion a year and an infestation can kill the fish or severely deplete output," he says. "The industry has identified sea lice as its top challenge as it costs farmers over €1 billion a year in losses. Given the scale of the potential problem – a pen typically has 30,000 fish but this can be up to 200,000 in Norway for example – the industry has been trying to contain it for almost 20 years. They have not been successful and all existing solutions have demonstrable drawbacks."

Tolerance

The favoured treatment was to put the fish in a chemical bath, but over time the lice built up a tolerance so stronger chemicals were needed. Now, these chemicals are overly toxic, unsafe for food production and harmful to the fragile marine environment, Casey notes.

"The next response was the development of mechanical treatments that have had limited success. They are typically abrasive and while they remove the lice, they can also damage the fish. Preventative measures like lice skirts are easy to deploy but they are not fully effective as they can restrict tide and flow through the pen and they don't work where there are large tides in countries such as Ireland and Canada. "

In the biology of a salmon the mucus layer is its primary defence mechanism against infection. If this is damaged, by brushing for example, the salmon is more vulnerable to disease. “Our treatment is non-invasive and will give the farmer healthy, lice-free salmon and improved yields without any collateral damage to the fish or the marine environment, “ Casey explains.

“By avoiding mortalities alone, the savings to the fish farmer will be around €105,000 per pen. Secondly, our treatment allows the farmers to maintain their organic status,” he adds.

Given the value implicit in developing a successful delousing solution, Casey is playing his cards close to his chest when it comes to the details of how his company’s technology works. “For now, we need to protect our IP so there is a limit to what I can disclose,” he says. “Basically, I have worked with photonics for years and decided to use it as the basis for a system that would kill the lice by exposing them to non-visible light waves.”

Examples of non-visible light waves include infrared and UV light. "We took the lice, put them in a lab in NUI Galway and kept testing until we found what I'll call 'light wavelengths of interest'. In a nutshell, the light kills the lice and our tests show they are all dead within hours."

The life cycle of lice is three to four weeks and this speeds up in warmer water. A female will produce about 1,000 eggs at a go. Given one louse on a fish can damage it, and a larger number can kill it, getting them all is critical.

The lice will be zapped as the fish move through a special lighting tube and this is where APS’ attention is focused at the moment. “We know our approach eradicates the lice and does not damage or kill the fish so we are very happy with the science. What we’re working on now is scaling up and developing out the technology for the tube through which the fish will flow,” Casey says. “This is where it gets complicated as you’re dealing with different sizes of fish and we have to find the optimum working distance of the light. Added to that are the challenges of dealing with a harsh marine environment.”

Volume

The next stage is for APS to trial its system on Irish salmon farms of which there are approximately 10. To begin with the company will arrive with its light unit in tow, treat the fish and leave. But eventually the idea is for fish farms to have their own units.

Initially, APS will base its fee on volume. “Our treatment will save farmers money because it’s effective and does not have the mortality rates associated with other treatments,” Casey says. “Salmon farmers worldwide are our target market, but Norway will be our sweet spot as it produces around 50 per cent of the salmon farmed globally.”

Solving the fish lice problem also has implications for food source sustainability the better use of resources to feed the world’s burgeoning population which is forecast to reach 9.8 billion by 2050. “Salmon aquaculture is the most efficient and fastest growing food production system in the world – twice as efficient as chicken and 10 times more efficient than beef,” he underlines. “Farmed salmon accounts for 70 per cent or over two million metric tons of the salmon consumed every year and this market is growing at five per cent per annum. Currently, global salmon farms provide 17.5 billion healthy meals every year.”

Casey has established a core team of five people and an advisory board to help him push on to the next phase. "The skills and insights of the team and the board have been key to moving this from an idea to a reality," he adds. "Furthermore, the significance of what we're doing has not been lost on the funding community. We have had support from private investors, State agencies including Údarás na Gaeltachta and the EU under the European Maritime & Fisheries Fund. To date, we have raised around €3 million and are funded until our commercial launch in Q1 of 2023."