Smelt Preferred water temperature?

First post is there any walleye guru's who kno what water temperature smelt are most comfortable
with an when they move to deeper water? Water temperature is finally rising!

Smelt spawn at 43 approximately same as walleye. Spent many years on Chicago & NW Indiana piers netting them b4 they went away. Always starting measuring temps in early March but was usually in April b4 they showed up.

Thanks for the info" Wallybagger" We troll custom crankbaits n wire out of Ashtabula an dont fish western basin as much as needed. Thanks again