Mercury linked to crashing Arctic fox populations

Scientists have established a link between shrinking numbers of Arctic foxes and their maritime diet, which has been found to contain high levels of toxic mercury, BBC reports.

A study of different populations of foxes in the Arctic region has revealed that groups feeding on ocean prey have poorer health and a lower body weight than the ones living in inland zones.

A team of researchers led by Dr Gabor Czirjak from the Leibniz Institute for Zoo and Wildlife Research was investigating the reasons behind declining numbers of Arctic foxes that were first reported in the 1970s, for instance on a small Russian island Medny in the North Pacific Ocean.

At one time, scientists believed this decline was caused by an infection, but studies failed to find a pathogen. What they did find was “significant rates of mercury” in hair samples taken from foxes and food they ate.

“They have high levels, compatible with the food, and it could explain the state of the foxes there… We know it is in the marine environment and it is causing exactly the type of symptoms that were found in this population,” Dr Czirjak told BBC.