Powan

The powan is a Scottish variety of the freshwater whitefish. Unfortunately its numbers are in serious decline and the lochs of Loch Lomond & The Trossachs National Park hold the only population of this fish in Scotland. The powan is therefore a protected species and must not be caught by anglers.

The powan is a distinctive fish with a dark bluish or green back and pale silvery underside. Compared with other species of whitefish, its fins are large and eye-catching. It can grow up to 46cm (18inches) and weigh 900grams (32 ounces).

In Loch Lomond, powan can be found over the whole loch. They can be seen depositing their eggs (spawning) in early January. Spawning takes place on certain gravelly shallows, usually those off headlands and on offshore banks and reefs. Sixty to seventy days later, the eggs will hatch and produce tiny fish (or fry) only 12mm (0.5inches) in length. Little is known of their early life, but they can reach up to ten years old in the right conditions.

One of the major factors in the decline of the powan is predation by the ruffe, a small spiny fish from the perch family. The ruffe is an invasive fish that competes with native fish for food and habitat and eats the powan eggs. Other factors threatening the survival of the powan is poor water quality; a lack of suitable spawning habitats; and barriers hindering migration.

Steps are being taken at Loch Lomond & The Trossachs National Park to try to protect the endangered powan fish and extend their range beyond Scotland.