Over the last couple weeks there have been reports from the middle and upper river regarding well mended escapee farmed salmon. I had a chance to look at one today on Castle Grant Beat 3. The fish was 79cm and weighed about 12lb. It was reasonably well mended with signs of new growth on the edge of the tail.
Although the tail on this fish was in reasonable condition it is a long way short of the quality of a true wild fish tail. A fresh wild fish has a sickle shaped tail tapering to symetrical points top and bottom and normally only has the odd blemish or split. The picture below shows a wild fish tail. The differences in the tail are subtle but when considered with other features such as heavy spotting, etc. farmed fish are normally identifiable.
Heavy spotting is another characteristic of farmed fish and as a result they are often mistaken for sea trout.
The head was also slightly misshapen below the jaw and the belly full with large egg sacs. The pectoral fins on this fish were not dissimilar to those on a wild fish.
For a fish with such well developed roe it was very silver, although the sea lice marks on the back suggest it wasn’t long in the river. Simon the beat ghillie made the interesting comment that escapees retain their silver colouring for longer than the wild fish, and that they fight very well!
I have heard of a few of these fish in the river recently and from photos on the internet it is clear they are turning up in other rivers as well. Who knows where these fish escaped from, the source may not even be a Scottish farm, being so well mended they may have been at sea for many months they may have come across the North Sea from a Norwegian farm. We took some scales for inspection so they may tell us a little more about its life history.
It can be really difficult to spot well mended fish such as these but the Fishery Board recommend that all escapees are killed so any slightly unusual looking fish should be scrutinised closely.