Because they are one of the most vorocious fish out there. People think pike are bad but a Pike has nothing on a rainbow.
For starters, the rainbows will try and spawn with native browns, sea trout and salmon. This means the native fish shed there eggs or milt, but nothing is fertilised.
Secondly, they will sit below spawning fish and snaffle the eggs.
Thirdly they predate on parr.
Fourthly they are fast. much faster than a Pike and can take fish that the Pike cannot.
Fifthly, at a smaller size they compete directly with native trout for food.
Sixthly (is there such a word
) when a cage is slashed several thousand fish suddenly end up in the loch/river..and no environment can support that sudden influx of fish.
The cages get slashed just about every year plus the trout farm at Almondbank has been flooded numerous times.
But none of this is new..the Tay has had rainbows in it for at least the 25 years I have been up here. One of the first fish I caught on the Tay was a rainbow. There are also sea run rainbows recorded (Steelheads) in the river and I believe it was last year that a fish of 14 pounds was taken, covered in sea lice.
