Dr. Ciaran Byrne:

It is extremely concerning. To be honest, one of the big factors is what we call marine survival. In 1983 or 1984, when 100 juvenile salmon left Ireland and took a right turn up to the North Atlantic, between 15 and 20 of those - in a good year, 25 - came back. By the mid-2000s, 100 fish would go out and up to the North Atlantic but only three to five might return. There is quite a decrease in marine survival and in biological terms there is always a multitude of factors for that. IFI has identified that, potentially, an additional 39% mortality can be due to poorly managed fish farms. There can be climate issues at sea. In some cases, we believe there are feeding issues at sea.