All anglers, who have fished Loch Leven over the years, will have their own theories as to what the causes were of its steady decline as a world-renowned fishery from the mid 1900s onwards. The loch and its catchment area have a wonderfully complex ecosystem, which means that a host of inter-related factors all probably played their part (ok, including predation by cormorants!).
However, foremost amongst the contributory factors must surely have been the deterioration in water quality caused by such factors as increased urbanisation within the catchment area, changes to agricultural practices etc. Increased loadings of phosphates, nitrates and the like were finding their way into the loch and creating big changes within the loch’s ecosystem, both within the water column and above it (eg fly life). Even to the casual observer, it was clear that something was going seriously wrong as weed beds died away and algal blooms proliferated. The low point was reached on 13th June 1992 when what was known as ‘Scum Saturday’ hit the national news headlines.
This turned out to be a vital wake-up call and prompted the various agencies to come together with Loch Leven Fisheries (Kinross Estate Company), the local farming community and others to produce a co-ordinated action plan effectively to save the loch. Perhaps to everyone’s surprise, the actions taken as a result of the agreed action plan do genuinely appear to have worked. As is backed up by scientific data, water quality has demonstrably shown dramatic improvement since those dark days in 1992. Anglers will have noticed the improvement in water clarity and the resulting recovery in weed beds as sunlight reaches deeper in the water column. It surely can be no coincidence that the indigenous Loch Leven brown trout have seemingly started to prosper in this aquatic environment where food supply has become ever more abundant. Whilst the apparent recovery in the fishing these past two seasons in particular may well derive from more than simply improved water quality, it surely has been a major factor. It is perhaps far too early to say that recent recovery represents a genuine and sustainable upturn in the loch’s fortunes as a brown trout fishery.
Despite Loch Leven being one of the most researched freshwater lakes in the country with detailed scientific data stretching back over 40 years, it is fair to say that its complex ecosystem is still only partly understood. It was therefore very exciting to be asked by Dr Linda May of the Centre for Ecology and Hydrology (CEH) for our support in their forthcoming application for grant funding of almost £3m towards a research project using Loch Leven as the case study. If the application is successful, the knowledge gained from this research project about the entire ecosystem of the loch and its catchment area would be invaluable. Kinross Estate Company (Loch Leven Fisheries) were only too thrilled to agree to become project partners with CEH and to provide every assistance with the project should it get the green light – here’s hoping!
On the subject of research into Loch Leven as a fishery, some may be interested to know that the Loch Leven Fish Research Group was set up in January 2008 to try to gain a better understanding into what was happening to the loch from the point of view of the trout. To give due credit to SNH, this was entirely their initiative and they have driven it from the start under the guidance of Denise Reed. Loch Leven Fisheries is obviously a core participant but, more crucially, other agencies such as CEH (water quality) and Marine Scotland (formerly FFL Pitlochry) are key members and provide expert input, as have others such as John Thorpe. It is hoped that the Forth Fisheries Trust will join the group.
Initiatives to date from this group have included fish surveys in the feeder streams, perch population monitoring (trapping), studies of the trout population in the loch itself (netting & hydro acoustic), water quality research and also cormorant monitoring. Much of this ongoing work will feed directly into the proposed large scale CEH research project should it be approved – however it will continue regardless should CEH ultimately be unsuccessful with their funding application.