By Mike Milne

As a child growing up on the Lake Huron shore, the spring die-off of alewives – making a fishy stinking mess of otherwise pristine beaches – was an annual event. A variety of herring that we called shad, those dead alewives were my first encounter with a Great Lakes invasive species.

Later, when a small harbour on Lake Ontario’s north shore was my home port, I recall yet another spring ritual as a government crew of technicians arrived to administer lampricide, to kill sea lamprey soon after they hatched.

Like the alewives, sea lampreys began entering the Great Lakes as canals and waterways were constructed when settlers moved into the U.S.A. and Canada in the 1800s. The invaders flooded in when the St. Lawrence Seaway fully opened in the 1950s.

Since then, the Seaway and the ocean-going ships that use it have introduced a plethora of invading species to the fresh water of the Great Lakes. Like the alewives, the sea lamprey didn’t just survive, but thrived. Lamprey were brought under control by an effective and very selective lamprey-killing chemical (applied annually to their lamprey breeding grounds), but the alewife population plummeted on its own, unable to withstand wide water temperature fluctuations.

Alewives were prolific breeders and weakened native species such as perch. The alewives’ innate weakness, however, killed off hundreds of thousands each spring during the 1960s and ’70s. By then, though, American and later Canadian government fishery biologists and sportsman’s clubs had introduced salmon – hatchery-bred predators that ate and were fattened quickly on a diet of alewives and smelt, as long as those invaders lasted. Today, with alewives and other bait fish increasingly scarce, the salmon-fishing bonanza is faltering.

If this is starting to sound complicated, it is. But there’s more. Compared to questions swirling around invasive species, the challenges of fluctuating Great Lakes water levels (discussed in a feature in the Fall issue of Boats&Places) seem simple. But for boaters who enjoy boating, fishing, swimming and relaxing on the freshwater seas, invasive species are a serious and increasing threat.

Since it’s winter and your boating options are limited, consider reading up on the subject. It can be scary and unpleasant, but so is a rocky, zebra mussel-infested shoreline. Just because you don’t like them, those mussels – first found in Lake St. Clair in 1988 and now throughout the Great Lakes – won’t go away on their own.

If you only have the time or patience to read one book this year, make it The Death and Life of the Great Lakes (W.W. Norton & Company), published early in 2017 and written by Milwaukee Journal Sentinel reporter Dan Egan, who has covered Great Lakes-related issues for the newspaper on a full-time basis for the last 14 years. His book is thoroughly researched and documented, authoritative but still easy to read – like a whodunit that exposes some of the culprits responsible for the destruction of what was once a diverse and productive ecosystem.

Canadian boaters who rarely visit Great Lakes ports in the U.S. can easily forget that the lakes are as much or more of a concern south of the border, since the inhabitants of seven major cities rely on them for drinking water, commerce and recreation.

As the same time, U.S. governance around the lakes is more complicated, with eight states and the U.S. federal government creating policy and providing funding, while a large Defence Department agency (the U.S. Army Corps of Engineers) takes responsibility for navigation, water-control and water level issues. By comparison, Ontario is the only province fronting on the lakes, Toronto the only major city and the federally funded Coast Guard handles navigational aids. On top of inter-governmental co-operation at all levels, the bi-national International Joint Commission has “regulating shared water uses” among its top responsibilities.

Egan’s book is a good education for Canadians on American perspective and involvement in the lakes, but also a reminder that the lakes hold about a fifth of the world’s surface fresh water. Many Americans and Canadians living on the lakes see nations or corporations who covet that water as the greatest threat to the lake’s existence and their own well-being. Not so, says Egan: “The biggest threat to the lakes right now is our own ignorance.” While Egan delves deeply into the threats of pollution and water level problems, he also looks closely into invasive species.

After 30 years, zebra mussels and quagga mussels are already endemic in the Great Lakes. The greatest recent threat is that four species of Asian carps, now flourishing in the Illinois River and Mississippi watershed, will cross into the Great Lakes via the Chicago Area Waterway System. Silver carp, that jump out of the water when alarmed by approaching power boats, make for popular Internet video clips. But invasive species, like former pet cobras that are now wreaking havoc with native fauna in Florida’s Everglades swamp, are a global problem.

Rats that first moved around on sailing ships were probably the original invasive species. Today, motorized shipping, air travel, trade and tourism mean invasive species are being introduced globally at an increasing rate.

On one hand, the invasive species problem is simple: humans are to blame. Pogo the opossum (in the comic strip created by the late cartoonist Walt Kelly) is widely credited with a similar observation. When confronted with pollution in a 1970 comic, he says to his pal, Porky Pine: “We have seen the enemy and he is us.”

Human travel, exploration, invasion, settlement, trade and tourism have brought the accompanying problem of invasive species. The Great Lakes, protected by rapids at Lachine, Que., a waterfall at Niagara Falls, Ont., and a height of land isolating them from the Mississippi watershed, would likely have remained relatively unaffected by invasive species were it not for settlers who brought population growth and widespread development. The Asian carps that government and non-governmental organizations on both sides of the Canada-U.S. border are trying to keep out of the Great Lakes were first imported by U.S. fish farmers, then inadvertently released into the wild by them and by fish biologists. In his book, Egan does a great job of tracking down carp-releaser #1. He says he regrets his action.

On the other hand, the current invasive species problem is complicated, because not all non-native species “invaded” the Great Lakes. Some were “invited”.

In recent years, as government agencies have grasped the enormity of invasive species problems, there have also been subtle changes in terminology, that perhaps better describe the situation. Some species, like alewives and sea lampreys, did indeed “invade” non-native habitat, but only because human activity made that possible. Humans have also intentionally introduced non-native species. So, the invaders may actually be better described, as they are by some agencies, as “aquatic non-indigenous species” or “aquatic nuisance species”. In current technical parlance, those species are only called “invasive” when they thrive to the point they displace native species, or when they replace a native species that was previously eradicated.

A poster that names and illustrates the ever-growing list of 184 species compiled by the Great Lakes Aquatic Non-Indigenous Species Information System, also includes brown trout, chinook salmon and other species that were intentionally introduced. Most are largely appreciated by anglers and rarely seen as ecological threats.

Simply showing those species alongside quagga mussels, tubenose gobies and ruffe is a tacit recognition that all “invaders” are not seen as being equal, but are in fact equally the result of human activity.

But just as humans have messed up the Great Lakes, they may also have the potential to help fix them. Legislation requiring ocean-going ships to dump all ballast water in mid-ocean and take on sea-water before entering the lakes has slowed the introduction of new unwanted species. Canada and the U.S. have strengthened joint work through pacts like the Great Lakes Water Quality Agreement, which now has Annex 6 focusing on invasive species. Great Lakes governors and premiers are working together under a mutual aid agreement and there’s a Great Lakes Panel working with a federal Aquatic Nuisance Species Task Force.

In Ontario, the National Marine Manufacturers Association (NMMA Canada) has a policy to “examine design controls which help prevent the spread of Aquatic Invasive Species.” The Ontario Federation of Anglers and Hunters continues to tell anglers and boaters how to avoid spreading mussels and invasive plants, while giving them a hotline and smartphone app for reporting 150 invasive species. There are thousands of reports every year.

There’s also a non-profit provincial Invasive Species Centre backed mainly by federal, provincial and municipal governments, working on invasives in general and Asian carps in particular. Through a website, it is suggesting that Canadians encourage the U.S. Army Corps of Engineers to strengthen its defences against the carp in proposed improvements to a canal and lock leading to Lake Michigan.

For me, one of the most encouraging developments on the invasive species front comes not from human action but from one of the lakes own relatively healthy native species – the lake whitefish.

For a few years, I heard rumours that Lake Huron and Georgian Bay whitefish were eating zebra and quagga mussels, and fish-handlers were dulling their filleting knives on the shell remnants. As Dan Egan reports in his book, that is true in northern Lake Michigan (connected by a strait to Lake Huron), where whitefish are thriving on mussels and have even developing stronger stomach muscles and an extra rib to digest them.

Through uninformed good intentions or unintended bad consequences, humans will likely continue to allow invasive species to make a mess of the Great Lakes. Whether their remedies succeed or not, nature or evolution seem just as likely to seek their own remedies. It seems like a small consolation for a clearly threatened ecosystem, but is somehow reassuring.

This article is featured in the 2018 Winter issue of Boats&Places.