I am not a 100 percent sure but i do recall a friend I used to fish with said ,there was a good number of them at lake san antonio here on the central coast.he told me at the time he was using bluegill as bait,and actually at the time bought some bluegill patterned swimbaits from me that i had.also i have read Folsom lake has them; see link http://folsom.uslakes.info/FishInfo.asp?FishID=46
unless i read that wrong of course.hope my info helps
brian