I did a quick search for info in regards to tilapia in CA.
It sure is hard to find anything..

When I did a search....I did see DIY was towards the top
of the 1st search page..
Problem is...Our link on the State Tilapia Regulations page seems to be out of date....doesn't go anywhere...
What little I did find elsewhere, says what I mis-stated...

Oliver, if you get a chance, would you please do an update to our info...?
State Tilapia Regulations