Sea lice and scientific evidence

Mon, Sep 23, 2013, 20:11

Sir, – Once again, Fintan O’Toole (“Something fishy about salmon farm evidence”, Opinion & Analysis, September 17th) does the nation a great service by exposing part of the fishy salmon farming story against our wild fish habitat. For over 30 years the sea lice emanating from the salmon farms have infested our migrating smolts resulting in less adult salmon return every season to spawn. Scientific reports have highlighted this fact but fish farm interests ignore the level of damage and our wild fish continue to die.

The Galway Bay fish farm application awaits the decision of Minister for the Marine Simon Coveney as part of his new 10 mega fish farm plan he announced some time ago.

But with such potential damage to our marine environment, tourism and economy, it must not be his decision alone. We, as anglers, are lobbying all the politicians to end this nightmare experiment as the scientific debate has been won long ago. We all know more than enough to avoid farming salmon or sea trout in Irish waters that cause amoebic gill disease and massive sea lice infestation as the past figures prove in Donegal.

It is time to leave this open cage fish farming industry to Scotland and Norway, with productions of 200,000 tons and 1.2 million tons respectively. Ireland can never compete at that level as our minuscule 10,000 tons of production makes the political decision not to grant any more licenses at present a much easier one. It is time to avoid any further gamble to our wild fish which supports 10,000 jobs and generate an economic impact of €755 million to our west coast of Ireland communities. The time has come for the Government to convene a sea lice summit and do the right thing by rejecting the application to grant the license for the first of 10 fish farms off our coast. – Yours, etc,


Federation of Irish Salmon

& Seatrout Anglers,

Teelin Road,

Carrick, Co Donegal.

Sir, — Fintan O’ Toole’s article dealt with aspects of the ongoing debate on the issue of sea lice on farmed salmon and their impact on wild stocks.

Mr O’ Toole referenced a Marine Institute paper on this subject, which was published after peer review in the Journal of Fish Diseases January 2013, and said “it seems the institute’s sums are wrong”.

We strongly refute this allegation. The Marine Institute paper (“Impact of Lepeophtheirus salmonis infestations on migrating Atlantic salmon, Salmo salar L., smolts at eight locations in Ireland with an analysis of lice-induced marine mortality”) presents an analysis of a long-term dataset from eight locations along Ireland’s west and south coast to determine the impact of sea lice on migrating salmon. It concludes that while sea lice-induced mortality on outwardly migrating salmon smolts can be significant, it is a minor and irregular component of marine mortality in the stocks studied and is unlikely to be a significant factor influencing conservation status of salmon stocks.

Another long-term Norwegian study (by Skilbrei et al), published in the same journal in January 2013, presents similar conclusions.

Mr O’Toole refers to a publication that questioned the methodology used by the Marine Institute. In the time-honoured practice for such matters the authors of the Marine Institute paper will respond, in the first instance, in the scientific literature.

It is regrettable that Mr O’Toole sought to criticise the Marine Institute publication before the authors were afforded the right of reply in the scientific literature.

We agree with Mr O’Toole’s assertion that we need “solid evidence-based expert advice” and that is exactly what we provide. – Yours, etc,



Chief Executive,

Marine Institute,