The Humber Marshes are one of the few remaining river mouth marshes in Toronto. These extensive marshes provide a breeding habitat for ducks, turtles and fish. Humber River's significance is being recognized by its designation in 1999 as a Canadian Heritage River. The Humber River watershed is the largest in Toronto. It is a significant corridor for migratory song birds and monarch butterflies. More than 60 species of fish live in the river including such sport fish as trout, pike and salmon. A sand dune marks the approximate location of the original Lake Ontario shoreline, prior to land filling. Near here was the site of a French trading fort in 1749 and a French merchant's cabin in 1790.