In 1924, Arctic charr from Lake Geneva were stocked into Lake Allos; a century later...

In 1924, Arctic charr from Lake Geneva were introduced into Lake Allos; a century later, their descendants showed distinct metabolic responses under identical conditions.

Researchers from Université Savoie Mont Blanc-INRAE found that the two populations of Arctic charr (Salvelinus alpinus) developed distinct physiological traits after only 100 years of separation.

Juveniles from Lake Allos consistently demonstrated elevated metabolic rates even when raised under controlled laboratory conditions, indicating rapid adaptation.

The study, published in Proceedings of the Royal Society B, suggests that cold-water freshwater fish can adapt to new environments much faster than previously believed.

The differences are attributed mainly to phenotypic plasticity, where organisms adjust to their surroundings, though genetic changes may also play a role.