A FIVE-year plan to rescue three major Lakes has been launched in a project which will help protect the 10,000-year-old species of Vendace and the famous Ospreys.

Bassenthwaite Lake and the surrounding rivers and streams which gush into it will be the key focus, although near neighbours Thirlmere and Derwentwater, will benefit too.

Experts said pollution, too much silt getting into the water supply, and invading fish and plant species, are putting the lake and its inhabitants at risk.

Bassenthwaite along with Derwentwater, house the only UK populations of Vendace fish, a species which has existed since the last ice age, 10,000 years ago.

To combat the problems, the Still Waters Bassenthwaite Lake Restoration Project has been launched to drive forward projects across the water's catchment area.

The area, measuring over 230 square kilometres or 88 miles, includes the fells around Bassenthwaite, all of Borrowdale, Thirlmere, and the east as far as Troutbeck off the A66.

John Pinder, the Still Waters Manager with the Penrith-based Environment Agency, said: "If something isn't done, eventually the lake will silt up at an alarming rate and water quality will get worse. Fortunately, thanks to this programme, we have a unique opportunity to do something about it before it becomes irreversible.

"But it will take many years of dedicated work across the whole catchment area, which feeds water into Bassenthwaite."

He explained that silt entered the water from eroded riverbanks, which had been overgrazed by trampling, which could then also collapse during heavy downpours.

More silt poured in off fells which hadbeen overgrazed because the soil quality had broken down.

Mr Pinder said: "In addition to filling up the lakes and making less room for vendace to live, when you get a storm and the wind churns the water around it deposits the silt on the beds where the fish are spawning and blankets them. They then have no oxygen and cannot survive."

Phosphates, which are regularly used on farmland and to encourage growth in gardens as well as being found in some household products like shampoo, also enter the water network and find their way to the Lake, which reduces oxygen in the water and encourages algal blooms.

Mr Pinder said: "Some techniques such as using straw bales in the lake to kill algae are too indiscriminate and don't solve the real problem. As well as killing other plants and animals, there is also a danger that the Ospreys could become entangled in the nets holding the straw. "But also dead algae sink to the bottom of the lake where they release their nutrients to feed the next bloom rather than being flushed out of the lake naturally."

He said: "What we need to do is to reduce the amount of phosphate getting into the lake and treat the source of the problem, rather than just the symptom.

"There are no quick fixes. It will take perhaps five years of work, but more than twice that for the lake to recover fully. Everybody can do something to help, even just being careful with fertilisers on their gardens."

Regulations have been introduced to combat the introduction of the Perch-like Ruffe, which is used as a live bait by Pike fishermen and feeds on the eggs of Vendace.

The control of invading plants like the New Zealand Pygmy weed which can grow prolifically, are among the measures to be taken.

The present level of phosphate is 25 microgrammes per litre, which has been reduced by the Keswick Sewage Treatment works, but it is hoped a water-phosphate level of between 15 and 20 microgrammes can be achieved.

Project partners include the English Nature, the Lake District National Park Authority, the National Trust, United Utilities, the Rural Development Service and the Forestry Commission.