West Cove - Private Property?

[jsm9437]

First off...excuse my ignorance.
On the south bank of West Cove there is a cut going into the marsh that has two small posted signs on them (one on each side). I think it is Apache Corporation.
Is this canal actually posted and enforced?
Or is this for the marsh off of the canal?
Basically....Can you go fishing in a boat down the canal and in the marsh down this cut?