If you bought a steelhead card, whether you fished or not, you are required to return it to DFG by January 31. the address is

   California Department of Fish and Game
   Steelhead Catch Report-Restoration Card
   P.O. Box 944209
   Sacramento, CA 94244-2090

You can also do this online now if you don't  mind setting up a login at DFG. Here is the link.