The study described in this report was commissioned by Marine Scotland, against a backdrop of concerns about the possible impacts of freshwater aquaculure on the health of wild salmonid populations in Scotland.
The authors conclude that:
• There does not appear to be a robust evidential case for suggesting radical and potentially expensive policy change regarding freshwater pen use.
• The least radical option in terms of costs would be mandatory improvement of containment. This would reduce but not eliminate most of the potential risks to wild stocks in those catchments in which pens are located. Tightening of the regulatory regime in this regard would not be unreasonable given the current state of knowledge regarding impacts. It would be logical for improvements in freshwater containment to go hand-in-hand with that for marine pens.
• Associated with improvements in containment, it is recommended that
o A formalised regime of sampling for escaped fish in catchments containing pens should be established, independent of the industry self-reporting system that currently exists. Details of such a scheme require further consideration: scope of sampling, how much it would cost, and how it would be funded
o Scientific Assessment of Impacts of Escapes. There should be a robust scientific assessment, probably on a specific catchment/project basis, of the actual impacts of farmed escapes, if and when they occur.