Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York. The Canada–United States border spans the centre of the lake.

Lake Ontario's native fish community is a diverse mix of cold-water and nearshore species, though many have faced significant restoration challenges. Iconic native "top predators" include Lake Trout, Atlantic Salmon (which were once extinct in the lake but are currently being reintroduced), and Burbot. In the deeper pelagic zones, you will find native prey fish like Lake Whitefish, Round Whitefish, and various "sculpin" species. The nearshore zones are home to popular native game fish such as Walleye, Yellow Perch, Smallmouth Bass, and Northern Pike. Notably, the Lake Sturgeon and the American Eel are two prehistoric native species that are currently the focus of intense conservation efforts due to their dwindling numbers. While the lake is famous today for "Chinook" and "Coho" salmon, it is important to remember that these are non-native species introduced in the 1960s to control the invasive Alewife population and create a sport fishery, unlike the truly indigenous species that have inhabited these waters for millennia.