Project helps rare fish species extend habitat to six more areas
ONE OF Scotland’s rarest fish species has established itself in lochs across Scotland -- after evolving to fit into new habitats, a study has revealed.
The powan, a type of freshwater whitefish, is endemic to only Loch Lomond and Loch Eck, and had been identified as vulnerable to extirpation.
In an urgent attempt to conserve the species, scientists helped by conservation managers introduced eggs and fish to six new loch sites over the past 30 years, with the aim of establishing new and robust populations.
A study led by a team at the University of Glasgow has now found that in just a few generations, the fish have adapted rapidly to the new environments, resulting in changes to their DNA, their ecology, and even their body shape.
Researchers found the new populations have lower genetic diversity than the original source populations, but not worryingly low.
The fish have been successfully introduced to Loch Sloy, near
Loch Lomond, and Carron Valley reservoir, in Stirlingshire. The other sites are not being revealed.
The powan is a species of high natural heritage value for Scotland. Its decline has been attributed to habitat destruction caused by climate change, increasing water temperatures and the non-native ruffe fish in Loch Lomond, which feeds on powan eggs and fry.
With the long-term health of the population depending on its genetic diversity and the evolutionary effect of translocation, the scientists wanted to find out how the populations changed, to look more closely at the species’ genetic health and determine if translocation was a successful strategy.
The study brought together fish biologists, ecologists, and evolutionary geneticists at the Scottish Centre for Ecology and the Natural Environment (Scene) and the Institute of Biodiversity, Animal Health and Comparative Medicine at the University of Glasgow; and the Limnological Institute at University of Konstanz in Germany and the UK Centre for Ecology and Hydrology.
The study, which used hi-tech genome analysis techniques, showed the translocated populations enjoyed a more diverse diet than the source populations.
Moreover, the study, published in the scientific journal Evolutionary Applications, showed translocated fish are tapping into specific regions of the genome in adaptive evolutionary changes to the new populations.
Lead author Dr Marco Crotti, who recently completed a PHD on these fish, said: “We can see evidence of the translocation as changes in the powan genome and their ecology, but they are genetically healthy and are establishing.”
Co-author Prof Colin Adams, director of Scene at the University of Glasgow, said: “This study is
The translocations show how fast adaptation and evolution can occur
important for biodiversity and conservation management: Actions to conserve fish populations need evidence of their success.
“This work shows translocations were a successful way to help Scottish powan. The translocations worked as an emergency measure, but the best mitigation is preserving the original populations.”
Co-author Prof Kathryn Elmer said: “The translocations show how fast adaptation and evolution can occur in wild populations, even in just a few generations.
“This is natural selection in action -- changes in DNA and genomes helping the fishes survive and establish in their new environment.”