Mississippi River has a great population of bull sharks in it. Some of them found further North are now thought to be sustained in full fresh.
(Sorry I had to)
As for the topic, they are 100% legal in CA when referencing the over all ban on potymotrygon genius. They are also not to hard for someone with a little experience under their belt....such as yourself. Good luck locating some. Maybe we could trade you for a certain large silver and red fish you have