Cathy2 has got that correct!
I haven't netted smelt on Lake Michigan for many many years and don't even know of there are any left in the Lake to make it worthwhile but I can tell you that smelt change very quicky when dead. I don't know what happens but there is a definite taste difference between just caught smelt and the stuff available in the grocery store.
If you can find a live source, please Post!-Dick