Case Study

HomeCleaning up sea lice in Scotland

Cleaning up sea lice in Scotland

Grieg Seafood Shetland have seen a reduction in lice burden of up to 70 per cent at several sites thanks to lumpfish produced at Benchmark’s recently revamped production facility on the island.

With its bulging eyes and toad-like complexion, the lumpfish might not quite be an obvious Hollywood hero, but it is now seen as having a key role in the growth of Shetland’s salmon aquaculture industry.

These hopes have been intensified by the establishment of the islands’ first commercial-scale production facility for the creature more commonly known as the lumpfish or lumpsucker. While a lone lumpsucker might not make much of a
difference, having a hatchery that aims to produce several million of them a year raises expectations considerably. For it’s not just the outlandish looks of the lumpfish that attract attention: it also has an ability to help the salmon sector overcome its biggest problem – thanks to its taste for picking parasitic sea lice off their salmonid hosts.

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Grieg Seafood Shetland (GSS), is one of three farms – along with Cooke Aquaculture Scotland and Scottish Sea Farms – who are currently producing salmon in Shetland, and all three are now beginning to invest in lumpfish as one of their key means of combatting lice.

As Grant Cumming, managing director of GSS, reflects: “We see from examples in parts of Norway and Scotland that cleaner fish can be used successfully over area management zones to keep sea lice infection pressure low throughout the cycle”.

However, he is also aware that such a strategy will only be truly effective if it’s pursued in earnest by all of the archipelago’s salmon producers and he hopes that the initiative will encourage greater collaboration between the competing farms.

We see no reason why it should not be possible by knowledge transfer and working closely with our neighbours that we cannot repeat that success in Shetland.

Grant Cumming


“We started working with lumpfish in 2014 and we had a lot of trouble with bacterial problems, but recently we’ve had very good results,” Adam Rainsden, Grieg’s Cleaner Fish Operations Manager, reflects, “and at one site this year we stocked half the cages with lumpfish and half without. Those that had the lumpfish experienced a 70 percent reduction in lice levels within eight weeks – and have managed to keep the lice levels consistently lower – so it was definitely not down to chance.”

Such good results have inspired many farmers to reconsider their initial opinions about cleaner fish.

“On site, we struggled to find buy-in. Farmers didn’t see it as something that was going to work… It was voodoo,” recalls Adam. “But now, after a couple of years and several generations, we’ve managed to get them onside. It took a lot of work, management and farmers working together, but now we see the results everyone’s on-board.”

I was pretty sceptical about using lumpfish. The first time we used them here we probably overlooked them slightly. This time, however, we’ve prioritised looking after the lumpfish more. I don’t think it’s going to be a cure, but they will play a big part in keeping down lice levels, which is obviously our biggest challenge here.

Laurie Manson

GSS’s Assistant Site Manager at PAPA LITTLE