Yep St Clair is freshwater. You'll find Bass, Golden Perch, Silver Perch, Catfish, Carp and Eel there. Worms work well for all species mentioned and yabbys too. With lures you can try poppers or any other surface lure in the morning for bass and maybe spinnerbaits, lipless crankbaits, deep-divers and even bladed lures for everything else. As i havn't fished the place personally, i'd look for stand of weed, dropoffs, submerged trees/logs or anything that would provide fish a good habitat.
If the natives aren't biting make sure to take some corn or bread for the carp and they can be easily caught.
Cheers
Goran