Climate change forces UK rare fish reintroduction further north

Plans to reintroduce one of England's rarest and most ancient fish to a key site in the Lake District have been abandoned because of climate change.

The vendace, Coregonus albulaa, a species of freshwater whitefish that can be traced back to the ice age, became extinct at Bassenthwaite (see map at right) in 1991 as a result of agricultural pollution, increased sediment and the illegal introduction of new fish species. It is one of only two lakes in England where the fish had survived.

Hopes that the small herring-like fish could be reintroduced once Bassenthwaite (right) had been restored to health have now been abandoned because of predictions of rises in future water temperatures.

There are also worries about the impact of climate change on the last remaining vendace habitat in England at Derwent Water (left), Cumbria. This has resulted in the Environment Agency making the decision to create a new refuge later this year that will be further north and on higher ground.

A spokeswoman said: "The warmer temperatures expected as climate change bites will put these rare, cold-water species under increasing pressure and we are currently exploring further transfers including moving vendace into Sprinkling Tarn, at the top of the Derwent catchment, during this year." (Right: Sprinkling Tarn with Derwent water Lake in background)

Ian J Winfield, of the Center for Ecology & Hydrology, who is an expert on the vendace, said that while the species is common in northern Europe, its genes have been mixed with other species. "The vendace is an iconic species because it is a glacial relic," he said. "It is a great pity if we lose this species, in part because the genetics of the population here are still pure."

Lord Chris Smith, the chairman of the Environment Agency, said the plight of the vendace was an early example of the impact that climate change will have on the UK.

He said warming is already occurring, with the temperatures of rivers taken by the agency over the past 30 years already showing an increase of 0.6C.

"These may be very small but it is a bit like a canary in the mine and something is definitely happening out there," said Smith. "What is difficult to say for sure is that it is directly attributable to man–made emissions. However, I find the science very compelling."

This is the second time that a conservation bodies have come together to try to rescue the vendace. In the 1990s the Environment Agency, the Center for Ecology and Hydrology and Scottish Natural Heritage (SNH) set up and funded the movement of vendace fry to Loch Skeen, near Moffat in south-west Scotland (map at left).

The introduction was a great success and there are plans to move the species to one more loch. There are now 10 times as many vendace per hectare in the Scottish loch (right) than at Derwent Water.

Vendace is not the only rare lake-dwelling fish to benefit from the creation of "refuge populations". Eggs were taken from some schelly living in Haweswater reservoir, Cumbria, hatched into fry and released into Small Water and Blea Water at the northern end of the Haweswater catchment, which is several hundred feet higher up.

Source:
The Guardian,"Climate change forces UK rare fish reintroduction further north", by Jo Confino, accessed February 14, 2011