The owner of Loch Leven has waded into the row over the running of the nature reserve.
Sir David Montgomery has spoken of his “distress” at the deterioration of the loch’s biodiversity during recent years.
He made his comments in the wake of criticism of Scottish Natural Heritage’s stewardship of the loch by landowner Michael C Smith.
Mr Smith, of Threapmuir Farm, Kinross, said failure to deal with a huge colony of lesser black-backed gulls was destroying the duck, wader, tern and small gull population.
Sir David, who in 1964 agreed for the environmental management of the loch to be taken on by what would become Scottish Natural Heritage, has agreed that failure to tackle predators has had an impact.
“In the 1960s and early 70s the loch was said to be one of the most important inland wetland sites in the UK, and possibly Europe, for breeding duck and waders,” said Sir David.
“It was also important for overwintering geese and duck.
“It is unfortunate that over the last 40 or so years many of the species of duck and waders have virtually disappeared and the numbers of those seen today are much reduced.”
He went on: “Today if one comes upon a duck with young they will be mostly under a week old and very few will reach eight weeks of age.
“The disappearance of the waders and other shore-based birds may, in part, be due to the lack of grazing by cattle on the foreshore and the resulting changes in the vegetation.
“The situation with the reduction and variety of breeding duck is different. If anything, there are more available nesting sites but survival rates are low.”
In the 50s and 60s: “Jackdaws, carrion crows and the larger gulls were routinely culled when they were attacking the breeding sites round the loch and, in particular on St Serf’s island,” said Sir David.
“St Serf’s no longer supports the large numbers of successful duck broods and the little black headed gull has all but disappeared. It is not many years since there were up to 10,000 pairs nesting on the island.
“Michael Smith and others are regularly reporting instances when the black-backed gulls are seen attacking and killing young broods of duckling. As there are now reported to be some 1,000 pairs of these gulls nesting on the island, it is not rocket science to see the effect they are having on the duck and other bird populations on the island, the loch and the surrounding areas.
“It really does distress me to see the deterioration in the biodiversity of Loch Leven that has taken place on my watch and I do wish that the powers that be would place more emphasis on true conservation and less on preservation.”
Denise Reed, SNH Tayside and Grampian operations manager, said that many things have changed during the loch’s 50 years as a national nature reserve “some for the better and, possibly, a few for the worse”.
She continued: Loch Leven is still internationally recognised for its waterfowl and wetlands. Many more people come out to enjoy the special character of the loch, boosting the local economy.
“One of the things that we agree is worse is that tufted duck numbers have declined.
“Long experience has shown that wildlife relationships are very complex and what may appear to be the obvious solution, often is not.”
She added; “The evidence doesn’t seem to support gulls as a major cause of the decline.
“We’re doing all we can to address the problem, including working in partnership with Kinross Estate through our long-standing nature reserve agreement, and expect to discuss the most recent developments once our analysis is complete.”