Habitat Recovery in Lake Ontario

Lake Ontario swims again: How once-fragile species are back in action

With careful management under the Toronto and Region Conservation Authority, several previously fragile species are returning to the GTA. At the very foot of Spadina Avenue, the city's first wavedeck undulates gently against Toronto's Inner Harbour. Its ipe wood and yellow cedar planks are an homage to the lakeshore's former natural contours, and people sitting on the deck's edge can peer over into Lake Ontario. If the water is calm and clear, they will likely see pike darting to and fro in the water. Lucky fishermen might even be able to catch one and bring it home for supper.

But the wavedeck has a surprising secret hidden below its curves. It sits atop a fish habitat installed by the Toronto Region Conservation Authority. "These were called fish condos," says Gord MacPherson, the associate director of restoration projects at the Toronto and Region Conservation Authority's Restoration and Infrastructure Division. "The construction guys were like, ‘Are you kidding me?' They thought there was no way it was going to work. We took tree trunks and embedded them in a block of concrete, and stuck them down there. Fish love that. When they put them in, the water was crystal clear, and the fish started moving in." The pike didn't come back overnight. "This was industrial land," says MacPherson. "They used to make artillery shells on this site during the First World War. The harbour had a smell to it when I was a kid."

In the 1970s, the emerging environmental movement led to a ban on phosphorus in laundry detergents; phosphorus runoff into the Great Lakes was causing massive algae blooms and blighting native aquatic plants. After phosphorus was banned, Lake Ontario slowly returned to health. Even in the 1980s, MacPherson recalls, the dominant fish species were carp and suckerfish. But with the return of the aquatic plants, and the installation of fish habitats along the waterfront, the pike (not to mention the walleye and bass) have grown in numbers. MacPherson says that a recent hydroacoustic survey of the harbour collected more than three million pings from pike; in past years, he says, the number was closer to three hundred . The harbour isn't the only place where formerly threatened species are thriving. Just to the west of the wavedeck is the Spadina Quay Wetland, a 2800-square meter wild zone that was a parking lot before the TCRA transformed it in 1999. The property was purchased at the cost of eight million dollars. Local high school students came for a few years to tend to the wetland; now, MacPherson says, the only attention it needs is the occasional garbage pick-up. The wetland is home to red-winged blackbirds, native grasses, and the occasional beaver or snapping turtle. In high-water years, it also provides a spawning ground for pike.

Source: YongeStreet

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