"Lakes Great Again, But New Threats Loom"

"A concerted 30-year effort has seen substantial improvement in the health of the largest freshwater habitat on Earth, but persistent and emerging problems exist prompting calls for further investment, legislation and long-term planning".

"CAMBRIDGE, ONT. -- Like the proverbial canary in a coal mine, the tiny rainbow darter is a sentinel species for the Grand River which flows through Southwest Ontario and empties into Lake Erie.

The minnow’s extreme sensitivity to pollution provides clear evidence of changes that are occurring more subtly through the river’s aquatic food chain and, more broadly, throughout the Great Lakes watershed.

For several years, male darters living in the Grand River downstream from Kitchener-Waterloo had among the world’s highest incidence of “inter-sex” characteristics, developing eggs in their testes. The phenomenon results from expsoure in the water to too much estrogen and other chemicals that interfere with reproductive development."

Shawn McCarthy reports for the Toronto Globe and Mail December 1, 2015.