Dan Egan on the Great Lakes
Indigenous people called them the sweetwater sea.
Their vast expanse boggled the minds of early European explorers, some of whom thought Asia must surely lay on its far shores.
We know them — and many of us depend on them — as the Great Lakes.
Superior, Michigan, Huron, Erie and Ontario account for almost one-fifth of the world's surface fresh water.
More than 30 million people live in the Great Lakes Basin, including almost one-third of Canada's population. They rely on the lakes for something as mundane and essential as the water they drink and and use to flush their toilets.
And yet, such a blessing of precious natural resources — freshwater and the countless fish that lived in the Great Lakes — rarely seems to have inspired good stewardship.
Cities dump raw sewage into the lakes, industry uses them as a waste dumpsite, and the Cuyahoga River, flowing through Cleveland into Lake Erie, has actually caught fire many times. Those are just some of the most notorious indignities visited upon the Great Lakes Basin.
But the greatest threat to The Great Lakes may have been biological pollution. Since work began 200 years ago to link the Atlantic Ocean to the Great Lakes via the Erie Canal, successive waves of invasive species have unravelled the food web.
In their wake, they've left scenes of mass carnage — huge die-offs of species that had thrived in the Great Lakes for millennia.
It's an often maddening story that Dan Egan recounts in The Death and Life of the Great Lakes, which has just been named by the New York Times as one of its Notable Books of 2017.
It's been compared to Rachel Carson's Silent Spring, which helped spur a North American environmental awakening fifty-five years ago.
"The bottom of Lake Michigan looks maybe more like the Caspian Sea than it does its historic self," Egan told Michael Enright, "and that's because invasive mussels now blanket — carpet — the bottom of the lake."
"If you were to get off the near-shore areas where the mussels can't take hold because of the surf, you could walk 80 miles (from the Wisconsin side) over to Michigan on a bed of quagga mussels at densities up to 100,000 per square metre."
Egan believes that the engineering feats of the 19th century opened the gates of the Great Lakes to invasive species.
Sea lampreys swam up the Welland Canal into Lake Erie and, along with over-fishing, caused much of the lake trout and whitefish to disappear, he says.
"[Lampreys] are a bloodsucker. They look like an eel, but they're technically a fish, and they suck the life out of their prey," he adds.
To fix this problem, Egan says, "we changed the lakes dramatically."
"We developed a poison to kill the lampreys, but by then, the lake trout were effectively gone, and unfortunately, behind the lampreys came alewives. Lampreys and alewives swam their way in up the St. Lawrence.
"You can say that this destruction of the top of the food chain in the Great Lakes was the result of canal-building. That's how we got lampreys and how we got alewives. And over here in Lake Michigan, by the mid-1960s, 90 per cent of the fish biomass was alewives with nothing to eat them."
Egan says the story of the Great Lakes shows the destructive nature of invasive species.
"They're a role player in their native habitat, but when they find a new place to live and thrive and where they have no natural competition or predator, things get out of whack real quickly."
"It sounds deceptively simple, but I think the most important thing you can do is, if you have kids, make sure they have a relationship with the Great Lakes," he says. "That's what we really risked in the 1960s, when people turned their backs on the lakes and their baseline had shifted all the way down to zero in terms of their expectations of being able to recreate safely on the Great Lakes."
"It's one of the easiest, most powerful things you can do, and that's raise a kid who loves the lakes."