Lake Ontario's lake trout have been a key indicator of pollution that affects humans and other species.
"When one thinks of iconic fish, Lake Ontario’s lake trout probably don’t come to mind. They don’t have the spear of a marlin or the taste of a tuna. There are no singing, dancing lake trout hanging on cabin walls. Great Lakes anglers often catch them while targeting the more popular chinook and coho salmon. But the white-bellied natives of these deep, cold transnational waters have a unique reputation -- one considerably nobler than taking bait or adorning plates: They are a barometer for global pollutants. For almost 50 years, whenever chemicals have been found in lake trout in Lake Ontario, they also have contaminated animals and people throughout the Great Lakes and farther north, in the Arctic. Its role as a toxic harbinger, begun in the late 1960s, continues as researchers recently discovered another unfamiliar flame retardant in the trout and in the Canadian Arctic's beluga whales."