Natural salmon outgrow hatchery fish

A 'natural' salmon rearing programme in Ireland has produced young fish that are six centimetres longer than hatchery-grown equivalents.

Ballinderry River Enhancement Project has been rearing salmon for a WWF restocking programme claims that young fish, which are kept in natural lakes and eat natural foods, such as insects and invertebrates, have grown considerably larger than intensively-reared farm fish.

The Project has released the first 1300 young salmon smolts into the wild so they can follow their traditional migratory route through Loch Neagh to the Atlantic Ocean. Another 400 smolts are due to be released shortly.

Alan Keys, Manager of Ballinderry Fish Hatchery Ltd told Practical Fishkeeping, "when our smolts were ready to go to sea they moved towards the downstream end of the lake. A specially constructed grill that had held them in the lake during the winter, was opened, allowing the smolts to be removed and marked each morning and evening. They are being stocked into selected tributaries of the Ballinderry River."

Keys says that the smolts eat insects and learn to catch their own food, some of which is produced from special underwater mats designed to boost the production of natural food items such as midges, caddis flies and stonefly.

The salmon should imprint on the tributary into which they are released and should instinctively return to this place to spawn when they reach sexual maturity.

The restocking programme has been organised by the WWF and has involved working with the local community to improve the habitat to make it fit for salmon to live in.

Alex McGarel, Freshwater Policy Officer at WWF Northern Ireland said: "Unfortunately the Atlantic salmon is fast becoming a rare species in our rivers. That's why we felt it was important to find new ways of improving their habitat but also to kick start numbers of indigenous salmon. We were keen to look at this new way of restocking which seems to be producing fitter fish."