My son, 14, was recently fishing a marina from his kayak. The main lake was too rough for his kayak so I told him to stay in and around the marina and see if he could catch any crappies. A lady (I'm assuming the marina owner?) rolled up in a golf cart and told him he needed to leave he was not allowed to the marina at all.

Please help me understand what is allowed and what isn't in this situation.

This is a complex issue. Suggest you check out this recent thread on the subject.

LBJ Owner Conflict

I'm my experience, The Corps of Engineers or the city has given more or less "water rights" to the marina or other private establishment as long as it does not interfere with common access to the body of water. If it is posted private marina/no fishing or you see purple it's a no go zone. He probably wasnt doing anything wrong, more of a safety for him and member boats accessing the main lake.

The LBJ issue is slightly different I believe. That is a homeowner with a personal dock. The dock is private, the waters are still public. Unless they purchased water rights with the contract of their home, which I've never heard of The Corps doing. But still I guess plausible.

what lake???

Marina's can have their own rules, and it's for safety and security reasons.
People leave their boats in slips long term paying dearly for that purpose, and the Marina tries to be looking out for their clients property when possible, so the operators tend to get a little excited when they see anyone that doesn't belong there, possibly snooping around disguised as a fisherman.
I might fish a marina, but if I'm told to move along I do, because I can understand why!

It might be public water, but you could say the same about a crowded parking lot.
Just try walking up and down between parked cars say looking for change on the ground, and not expect someone to approach you asking you to leave

"Navigable waters" are open public property. Now I don't know at what point you stop being navigable? Sitting in a slip?

Marinas are great places to fish. Don't tie up and they really have little recourse.

I'm really shocked by some of these answers. It is perfectly legal to fish around marinas. They might tell you to leave. Tell them to call a game warden

Okay, so I did call the Game Warden and he told me the marina owners pay for that area we needed to abide by their rules.
I totally completely disagree with that 100%. He knows enough to NOT fish a slip that has people in it but it was 6am and no one was around.

Crazy.

Call his boss and get him educated. You will find that he is wrong. They own the docks, bit not the water underneath and around them.

Quote from TPWD website:
Q: Can a marina operator or lakeside landowner keep boaters away from his docks?

A: Not on public water. If a lake is public water, the public has the right to boat the entire lake, and to fish from a boat (subject to regulation by government entities).31 A person who interferes with a lawful boater may be committing the crime of obstructing a waterway and/or harassment. Both are Class B misdemeanors.32 By the same token, a boater who unreasonably obstructs access to or from a dock or boat slip may be guilty of obstructing a waterway.

This was also in Oklahoma. But that shouldn't matter.

His exact reply was "The marina's are technically privately owned. They lease that property from the Corps. They charge people to fish their docks. They can ask people to leave.

I think that he is right. Marina owners can ASK people to leave. But they can't make you do so if you're on the water and not on their actual property, the docks....

In Oklahoma Corps of Engineers set a 50ft no fishing near Marinas in conjunction with the Dept of Tourism. Neither imposes the rule, but allows it and sides with the Operator. They make the claim over property damage and safety.