From the CA fishing newsletter:
"After several months of California lakes and rivers empty of fishing rods, anglers return to waterways filled with eager trout on opening day of the 2018 trout season. Don't miss a minute of the action. Make sure you have a fishing license in hand before it all starts.
The general trout opener will commence on Saturday, April 28, one hour before sunrise. Most lakes, rivers and streams have a limit of five trout per day and 10 in possession. However, regulations differ on season opening and closing dates, bag limits, minimum and maximum size limits, and gear restrictions."
Be sure to purchase your 2018 license if you haven't already and check the regulations before heading out.