Photo credit: Eco-evolutionary dynamics lab, McGill UniversityWhen scientists from McGill University learned that some fish were proliferating in rivers and ponds polluted by oil extraction in Southern Trinidad, it caught their attention. They thought they had found a rare example of a species able to adapt to crude oil pollution.

At a time when humans are imposing an unprecedented burden on the world's ecosystems, studying how organisms can tolerate pollutants is crucial to understanding the impact of human activities–and to helping to mitigate it in the future.

Related article: Study Details Impact of Deepwater Horizon Oil Spill on Beach Microbial Communities

Led by Dr. Gregor Rolshausen, then a postdoctoral researcher at McGill working with Prof. Andrew Hendry, the team went to study the guppy fish living in polluted areas, comparing their morphology and genetic makeup to those of similar guppies from non-polluted parts of Trinidad.

But the key to the guppies’ survival in oil-polluted waters was not what the researchers had expected. Prof. Hendry explains:

Do stressful conditions make adaptation difficult? Guppies in the oil-polluted environments of southern Trinidad, in Evolutionary Applications, Volume 8, Issue 9, pages 854–870, October 2015.

By Gregor Rolshausen, Dawn Phillip, Denise Beckles, Ali Akbari, Subhasis Ghoshal, Patrick Hamilton, Charles Tyler, Alan Scarlett, Indar Ramnarine, Paul Bentzen and Andrew P. Hendry