With the shortest water depth of any of the Great Lakes, the shallowest average depth and the warmest temperature, Lake Erie is the most susceptible to climate change and pollution. It’s also the most urbanized of the Great Lakes and has a higher population density, making it more vulnerable to erosion, nutrient pollution and invasive species.

Harmful algal blooms are fed by excessive nutrients like phosphorus that enter the water from fertilizer runoff on farm fields and effluent from sewage-treatment plants. They kill off natural vegetation, clog water intakes and degrade beach quality and aquatic habitat. They can even produce toxins that threaten drinking water supply, cause skin rashes and gastrointestinal problems and make people sick when they eat lake fish or drink the water.

Invasive species compete with native plants and fish, harming their populations and causing them to die out. Some, like zebra mussels, compete with other species for food and crowd out native fish. Others, like gobies, grass carp and sea lampreys, are responsible for costly damage to infrastructure and clogged water intakes. And then there’s the problem of blue-green algae, which release potent toxins.

Fierce storms can wreak havoc on the lake. One of the worst was on Dec. 9, 1909, when a fierce blizzard sent three ships to the bottom of Lake Erie with 53 sailors aboard. But even in calmer weather, the lake’s moods can be unpredictable. It’s a gamble for commercial fishermen, who begin their season in March when the ice melts and continue until the freeze-up at the end of December. They rely on radar, ship-to-shore radios, fog sirens and periodic weather bulletins to keep them safe.