Outdoors: Survivors since the Ice Age, vendace are now found in only a handful of places

THE HUMBLE vendace was once a common staple of the good folk of Lochmaben in Dumfries and Galloway, who even held special parties in celebration of their esteem for the small herring-like fish.

In times past it swam in abundance in the nearby Mill and Castle Lochs, but today it’s one of Scotland’s rarest and most endangered freshwater fish.

Deterioration in water quality combined with the impact of non-native water plants and fish saw the vendace disappear from Castle Loch in the first half of the 20th century and Mill Loch in the early 1970s, the only sites in Scotland where these silvery plankton-eating fish, commonly 10cm to 20cm long, occurred. It is said that Mary, Queen of Scots brought the vendace to these lochs from Europe in 1565, but this is no more than a fanciful yarn, for it is in reality one of the few freshwater fish that managed to colonise Britain at the end of the last Ice Age nearly 13,000 years ago.

But now a remarkable rescue programme is underway to save this important part of our natural heritage. In the mid-1990s, an action plan co-ordinated by Scottish Natural Heritage (SNH) and the Environment Agency was launched to create refuge sites for vendace utilising the two surviving indigenous UK populations that were still hanging on in the Lake District at Derwent Water and Bassenthwaite.

Under the plan, fertilised vendace eggs and small fry from Bassenthwaite were introduced into Loch Skeen near Moffat in Dumfries and Galloway. Loch Skeen is a remote upland loch lying above the famous Grey Mare’s Tail waterfall, and scientists believed it offered the ideal conditions for vendace to thrive. They were proved right and by 2003 it was established that were was a good breeding population of vendace in the loch.

This success proved all the more important shortly afterwards with the discovery that the vendace had become extinct in Bassenthwaite. This genetically unique population had been saved just in the nick of time with the fish now safely holed-up at their refuge site at Loch Skeen. Recognising the importance of creating such sites, vendace eggs and fry from Derwent Water were then transferred to Daer Reservoir in south Lanarkshire in the hope of creating a similar refuge for this fragile population.

Unfortunately, the newcomers appear not to have survived, or at best the population is at a very low level.

The apparent failure at Daer Reservoir underlines the complexity of vendace biology, as this site (as well as Loch Skeen) was selected from a number of other locations on the basis of such things as water chemistry, availability of spawning substrate and presence of other fish species. In the meantime, another introduction of Derwent Water vendace has been made into Sprinkling Tarn in Cumbria and Loch Valley in Galloway. Fish from the newly established Loch Skeen population have also been transferred into another south-western loch to create an additional holding stock for other possible introductions at a later date.

Dr Colin Bean of SNH, who is leading the initiative to save the vendace in Scotland, is in no doubt about the importance of the fish to our ecology. It is, he says, a unique relic of the last Ice Age that maintains an important place in our cultural and natural history.

“In Scotland, there used to be a local market for the fish in the Lochmaben area and the population used to hold vendace parties,” he says. “Indeed, there is even a street in Lochmaben which retains the name Vendace Drive.

“After the last Ice Age the vendace was one of the few fish that managed to colonise Scotland and the whole story of our fascinating freshwater biodiversity can be linked back to this time. The vendace is of incredibly high conservation value, not least because the remaining populations have been isolated for so long that they are genetically unique.”

The similarly threatened powan, a close cousin of the vendace whose natural distribution in Scotland is restricted to Loch Lomond and Loch Eck, has also been given a helping hand, with successful introductions having been made at a number of sites in central Scotland and Argyll. It would seem that such introduction schemes are playing a vital role in ensuring that our interesting diversity of freshwater fish life is not lost for ever.