Prior to the building of the sluice gates and the lowering of the water level in 1830 –1832, a large variety of different species of fish were to be found in the nutrient-rich waters ofLoch Leven. Historical records suggest species such as atlantic salmon, trout (brown, grey, speckled, black head), charr, pike, perch, eels and flounders
Once it became impossible for fish to run into the loch from the North Sea, the number of species has dwindled. Nowadays, the main inhabitants are the famous Loch Leven brown trout. Of the other species, only the pike and perch remain and there are signs that the numbers of both are starting to recover after being almost wiped out during the last 20 years.
Many anglers consider the Loch Leven brown trout to be the perfect trout, both for its graceful form and for its sporting qualities. The species is classified as Salmo Levenensis and, when found in Loch Leven, is clearly distinguishable on account of its dark colouring and pink flesh. The quality of the trout owes much to the quality and abundance of food which the loch affords.
Over the last 150 years, Loch Leven brown trout have been introduced to waters all over the world, from New Zealand to South America (and most places in between!). The first documented introduction of the Loch Leven trout to North America appears to have been made in Long Pond near St John’s, Newfoundland, in 1884 and the species can now be found in every province except Prince Edward Island.
When introduced to other waters,Loch Leven brown trout interbreed freely with any other brown trout in the water and rapidly lose their distinguishing characteristics. This change in appearance also occurs even where there are no other species of brown trout present. The only way to see the trout in its true state is at Loch Leven.
The loch itself does not produce large-sized brown trout with the average size of fish landed weighing in at around 1 1/2 lbs. Occasionally, specimens weighing over 7 lbs are landed but the record remains the 9 lb 13 oz trout caught by Colonel Scott on 8th September 1911, which can still be seen in a glass case mounted on the wall of the Bistro. The trout was actually hooked by fly through the back fin and apparently gave Colonel Scott and his boatmen (John Flockhart and his son John) “a very lively two hours before being landed”! In 2011, just 5 days short of the 100th anniversary of Colonel Scott's record, Michael Mackenzie landed the 2nd largest trout ever on Loch Leven, weighing in at 9 lbs 6 ozs.
Elsewhere, the species flourishes in warmer waters in more temperate climates and have been known to grow to over 20 lbs. On Loch Leven itself, the brown trout make up for their relative lack of size with their renowned fighting qualities.
Amid considerable controversy, rainbow trout were first introduced to Loch Leven in 1993 following an agreement between Loch Leven Fisheries and Scottish Natural Heritage. Although initially the rainbows flourished in Loch Leven, their success proved relatively shortlived and the experiment was discontinued in 2004 when it was decided to revert back to the Loch being a pure brown trout fishery once more.
Anglers are by no means the biggest threat to the trout in Loch Leven. Nature’s predators include cormorants, grey herons and ospreys whilst, below the surface, pike seem to be making a comeback.
The biggest threat undoubtedly comes from cormorants (Phalacrocorax Carbo Carbo) which inhabit Loch Leven in large numbers. However numbers have decreased in recent years following the cessation of stocking the loch with young trout reared in our hatchery.