Sea lice not an issue for salmon stocks, says BIM

Bord Iascaigh Mhara (BIM) has claimed that new research from NUI Galway and the Marine Institute published in the Journal of Fish Diseases shows sea lice infestation is unlikely to be a significant factor influencing the conservation status of salmon stocks.
This research was carried out over a nine-year period (2001-2009) by the Marine Institute and NUI Galway and involved more than 350,000 fish, released into eight different rivers in 28 separate experiments. It investigates the impact of sea lice on the marine mortality of Irish salmon smolts and assesses the extent of sea lice-induced mortality in Irish Atlantic salmon stocks.
In this long-term study, one group of salmon smolts were treated with a commercial agent, which protects them against sea lice infestation for eight weeks after going to sea. The return rates of controlled or unprotected mirror groups of fish were compared with the ‘protected’ fish to see if they suffered any additional sea lice-induced mortality following release into the sea. The research also took account of the results of a similar but smaller study by Inland Fisheries Ireland.
Donal Maguire, director of aquaculture development services of BIM, stated, “This is confirmation of the validity of the approach that BIM has taken with regard to the development of the aquaculture industry. The scare stories in relation to sea lice being a threat to wild salmon put out by the opponents of salmon farming have no basis in scientific fact.
“Ireland is blessed in having an environment naturally suited to salmon farming and all stakeholders should now unite to realise the opportunities this represents and to deliver much-needed economic and employment benefits to coastal communities,” Mr Maguire said.
BIM has said, “Because the Marine Institute study involved the repeated release of hundreds of thousands of fish over the course of a decade across eight locations in Ireland, its results are highly accurate and very reliable. It found the level of marine mortality attributable to sea lice infestation to be very small – approximately 1% in absolute terms.” ‘At these levels, it is unlikely to influence the conservation status of stocks and is not a significant driver of marine mortality’, the article states. The paper also offers an explanation as to why some researchers in this area have reached different conclusions and demonstrates serious flaws in the experimental design employed by these research groups.”