Proposals would destroy Canna's natural heritage, according to the Trust.
A proposed open pen fish farm would destroy the cultural and natural heritage of a Western Isle, according to the National Trust for Scotland (NTS).
The conservation charity said the plans submitted by seafood firm MOWI pose an “unacceptable threat” to the marine environment and tourism economy of the Isle of Canna.
NTS has now officially lodged its opposition to the scheme in a letter of response sent to Highland Council this week.
In their response, the charity lists a string of “key issues of concern” which, it claims, MOWI has failed to address.
These include the proposed location of the farm, which would impact on two Special Protection Areas and the Small Isles Marine Protected Area, home to protected and extremely rare marine wildlife
Any farm would also produce massive amounts of organic waste, mainly faeces. The NTS said plans to house an estimated 2,500 tonnes of salmon in open pens would produce the same amount of waste as a town of 33,000 people, and criticised MOWI for not properly assessing the environmental impact of this waste.
Concerns were additionally raised about rats being reintroduced to Canna from shipping associated with the farm, and the likely shooting of seals to protect stocks.
Elevated numbers of sealice would also be likely to affect wild salmon and sea trout up to a 35km radius from the site, the NTS said.
Finally, the letter concluded, tourism would be likely to suffer from the additional shipping and infrastructure needed to service the farm.
Stuart Brooks, NTS head of conservation and policy, said: “The protection of the cultural and natural heritage of Canna on behalf of the nation is our responsibility.
“Based on the information provided by MOWI so far about their fish farm proposals, we have no confidence that their plans would not undermine, if not destroy, the very things that make Canna so important.
“In all conscience, we cannot support MOWI’s proposals. We would be failing in our core purpose as a conservation charity if we did, as well as betraying the wishes of John Lorne Campbell, who donated Canna and Sanday to our care.”
Clea Warner, the Trust’s general manager for the North West and the Islands added: “This is clearly a sensitive matter for the residents of Canna and we spoke with their representatives last week to share our conclusions.
“The Isle of Canna Community Development Trust will form its own views and communicate when they are ready. We have shared our response with them and remain committed to working with the Canna community.”
