Most the canals in question are not natural watwerways, they were dug so now they are tidal. Only people that have a right to be in there are the oil/gas company and the landowner and whomever he/she grants permission.
The other issue is erosion. Many of the places that were pristine marsh are now open water, however the survey lines will still show that the landowner still owns that property even though it is now water. They still pay taxes on that and will ultimately be liable if someone was to get hurt on that property. Just because you can float a boat in there does not mean you can hunt and fish in there.
This has always been private property, and the landowner never enforced or cared about people being in there. A few bad seeds were stealing crabs and crab traps and vandalizing his property so he put an end to that. I think we would all do the same in his situation.
That being said, there are some places that are natural bayous and waterways that adjacent landowners have placed posted signs and gated that should not be gated, this is not one of those though.
My two favorite lakes off the Oua****a River had this very thing happen. There was one entrance into them (even at pool stage) and the landowner(s) placed in a levee and culverts there, the culverts too small to get a boat into, so now he has his own little paradise back there that no one can fish/hunt
