THE escape of 33,000 rainbow trout from a fish farm in the Highlands has reignited concerns for the future of salmon in Scotland.

Wild salmon catches in Scotland are already at their lowest level since records began, according to government figures released earlier this year, while Fisheries Management Scotland said new data highlighted stocks of the fish are at “crisis point”.

But who’s to blame, and can the problem be tackled?

What do rainbow trout have to do with salmon?

Rainbow trout, which are not native to Europe, are considered one of the world’s worst invasive alien species. They prey on juvenile wild salmon and also compete for food with native salmon and trout.

Friends of Loch Etive (FoLE), a charity opposed to “commercial exploitation” of the loch, estimated that there have been 30,000 reported rainbow trout escapes into Loch Awe and Loch Etive since the first of 2008, the same year seafood producers Dawnfresh took over the farm.

How bad is this so-called salmon crisis?

Levels of wild salmon in Scotland are at their lowest since records began, it was recently revealed.

At the end of 2018, the last Scottish wild salmon netting station closed because there were so few fish to catch (that means wild salmon is off the menu, with only farmed salmon widely available).

The total reported catch through rod fishing was 37,196 for 2018, which was just 67% of the previous five-year average total.

Farmed salmon stocks are also collapsing due to infestations of sea lice, which have in turn affected wild stocks. Scotland’s biggest salmon farmer Mowi in March revealed the amount of gutted salmon it produced from Scottish waters fell by 36 per cent in 12 months, blaming infestations of sea lice and disease.

Alan Wells, chief executive of Fisheries Management Scotland, said the figures confirmed that wild salmon levels are “now approaching crisis point” and called on the Scottish Government and regulatory authorities to “do everything in their power to safeguard the species”.

What - or who? - is to blame?

Water degradation, management infrastructure such as dams, along with open-net salmon farms, climate change and soaring demand for salmon have all been blamed for taking a toll on Scotland’s wild salmon.

However last year the salmon farming industry came under fire for “shocking” levels of fish deaths as it emerged the country hit record levels due to diseases and parasites.

Campaigners have claimed fish farms are to blame for wild salmon deaths as a result of sea lice originating from the farms.

A BBC Panorama programme last month described how infestations of sea lice in some areas has seen fish “eaten alive”.

Producers like Dawnfresh have also come under fire for their open-cage farming methods.

Andrew Graham-Stewart, Director of Salmon and Trout Conservation Scotland, said: “One of the most critical factors is the impact of open-net salmon farms, in particular the release into the wider environment of vast numbers of deadly parasitic sea lice, on wild salmon numbers.”

What is being done to address the problem?

The latest rainbow trout incident has sparked calls for regular Marine Scotland to consider relocating fish farms out of Loch Etive.

The salmon farming industry has insisted it is working hard to find solutions to the problem of sea lice, and is making progress in rearing so-called cleaner fish, avoiding the need for damaging chemicals.

And fish farms will have to report weekly levels of sea lice under new government rules.

Environment secretary Roseanna Cunningham said the Scottish Government had “identified 12 groups of high level pressures on the species” and had committed £500,000 to funding research to better understand the problems and “mitigate against it”.