The River Carron in Wester Ross has gone from having hardly any returning fish being caught by anglers to more 300 a year, the Aberdeen Press and Journal reports.
Bob Kindness, manager of the River Carron restoration project, has used an unorthodox stocking programme to turn around the river’s fortunes.
For nearly 20 years, Mr Kindness, a lecturer at Inverness College, has boosted salmon numbers using controlled fertilisation and restocking – dubbed by some as “IVF for salmon”, the newspaper reports.
Mr Kindness’s operation is based at a site with 16 large tanks and several pools near the village of Strathcarron.
He breeds female salmon from wild eggs – taken from fish he has caught on the Carron – later stripping them of their eggs to spawn a generation of new fish, which he grows in captivity before releasing them into the wild.
Last year, he was able to release 330,000 young fish into the river, but his project has attracted criticism from conservationists.
“The scientific evidence from around the world is crystal clear – hatcheries harm wild salmon,” Don Staniford, from the Global Alliance Against Industrial Aquaculture told the Press and Journal.