A new scheme pioneered by Stirling University scientists is set to transform the costs and productivity of the Scottish farmed salmon sector, boosting the profitability of the £500m a year export industry and tackling the problem of sea lice which was described at an industry forum last year as the "single biggest issue facing the salmon farming industry".

 

The £4 million research project, launched last week, aims to reduce the widespread use of environmentally damaging chemicals to control pests such as sea lice, by adding a lice-eating fish called the ballan wrasse to salmon cages.

Although there are no records of the number of Scottish farmed salmon that are discarded each year because of sea lice infestation, one study claims that the cost to the industry of dealing with sea lice is between 7 and 10 per cent of total production value.

Scottish government figures, meanwhile, put the mortality rate for the 40 million salmon put to sea in 2013 at 9.2 million, or 23 per cent. However there are no figures for the number of those that die from sea lice infestation.

The 42-month wrasse project is the first research programme to be funded by the recently-established Scottish Aquaculture Innovation Centre (SAIC) and follows on from the accidental discovery of the propensity of wrasse to "groom" other fish. Salmon farmers in Scotland and Norway noticed that fish whose pens had been infiltrated by wild wrasse had far fewer sea lice than others.

Wrasse's reputation for "delousing" other species has already led to a small number of fish farms in Scotland experimenting with using wild wrasse native to Scottish waters as well as lumpfish to reduce sea lice in fish farms. The Stirling project aims to make the process applicable across the industry.

The industry's commercial success, which last year saw Scottish salmon become the UK's top food export, has come partly at the cost of its reputation for sustainability.

Conservation campaigners have slammed producers for using hundreds of kilos a year of allegedly toxic chemicals like the organophosphate azamethiphos, which attacks the nervous systems or shells of parasites, to control sea lice in salmon pens.

The publicly funded SAIC's grant of £831,530 towards the wrasse project has leveraged in private sector contributions of £3 million from Scotland two largest aquaculture companies Marine Harvest and Scottish Sea Farms as well as from fish feed multinational Biomar. Stirling University will also provide in-kind support through the sponsorship of two doctoral studentships.

Professor Hervé Migaud of the Institute of Aquaculture at Stirling University told the Sunday Herald that a preliminary study carried out over the last three years using wild wrasse established that the fish can co-habit with salmon in the same pens. It was, for example, established that salmon and wrasse have their own feeding patterns and do not eat each others' food.

But Migaud says that the large-scale use of wild wrasse would not be sustainable, which is why the larger second stage study examining how to use farmed wrasse is needed.

Launched at Stirling University's Marine Environmental Research Laboratory at Machrihanish last week, the research project will focus on developing wrasse hatcheries, establishing good husbandry, promoting fish welfare and improving understanding of the biology and life cycle of the wrasse.

"What we are creating is a biologically harmonious sea lice control regime that will help us move towards a more sustainable form of aquaculture" he said.

According to Heather Jones, chief executive of SAIC, the cleaner fish project could help the Scottish aquaculture industry reach its target of increasing farmed fish production to 210,000 tonnes by 2020, a 30 per cent increase from the 162,000 tonnes estimated to have been harvested last year (and down from the 165,256 tonnes produced in 2013).

The 2020 growth target was set by the industry in 2009 in response to growing demand for Scottish salmon from around the world particularly from China and in response to concerns that jobs and sales could be lost to Norway if Scotland fails to increase production sufficiently. Around 70 % of Scotland's farmed fish sector is already owned by Norwegian companies.

If the 2020 production target is met it would, the industry calculates, increase turnover across the supply chain from over £800m to £1.1bn and see the number of production jobs - many in remote and economically fragile parts of rural Scotland - increase from 1100 to 1450.

If the wrasse project is successful it could lead to the creation of further new jobs in farmed wrasse production and management.

"I am hoping that this project will lead to an environmental pay-off, an economic pay-off and a fish welfare pay-off," said Jones.

Jones also points to the fact that the demand from certain countries for the highest quality salmon could be easier to meet if the project is successful.

"The Japanese market for salmon for use in sushi is a premium market that requires whole head-on salmon for export that have no external blemishes or lesions [caused by sea lice] so this project could help with that," Jones said.

A feature of the project is that the research results will be published in the form of an "open knowledge" handbook so that the whole industry can learn from it for free.

Steve Bracken of Marine Harvest said that if the project is successful in deploying wrasse to control sea lice it will open more sites for use in aquaculture, reduce fish medication costs and boost productivity.

"All parts of the industry - from large companies through to SMEs - will see benefit from this and the already-excellent reputation of Scottish salmon will be enhanced," he said.

Lang Banks, director of WWF Scotland, said that any move by the aquaculture industry to reduce reliance on chemicals to deal with sea lice was welcome.

"There is no doubt that sea lice are a major problem for the Scottish sea farming industry and that large amounts of chemicals are used to combat the problem.

"We welcome this project as an alternative way of dealing with sea lice which would not result in so many chemicals getting out into the environment. Although the amount of chemicals is licensed and controlled, over time they can accumulate in the environment."

Scott Landsburgh, the chief executive of the Scottish Salmon Producers' Organisation, said he was hopeful that the project could lead to smaller amounts of chemicals being used by the industry in the long-term and could also boost industry productivity.

"We as an industry can't eliminate sea lice as they are endemic in the wild so we will continue to use mitigation measures, such as using cleaner fish and washing fish in hydrogen peroxide at a low concentration to get rid of lice.

"If the project is successful it could lead to higher yields at fish farms and that would make them more productive," he said.