The primary purpose for the canal is marine navigation. That is the top of the list without question. Secondarily is recreational use (walking/biking the service road, camping and fishing amongst others). The Army Corps of Engineers manages/maintains the whole thing. I don’t think “closed to fishing” is as difficult as you might think. I’m not sure of the politics or procedures, but me thinks if the ACOE decides fishing has become a real problem for navigation or other recreational activities they can wave a wand and shut it down fairly swiftly. My gut tells me they are keeping a running tab on all the nonsense like poaching, casting at boaters, issues with the RR tracks, litter and other nonsense and could likely build a case for some sort of closure or other regulations.
Another factor is area residents and businesses. There are a few movements afoot to close parking in some of the residential neighborhoods. I don’t blame them one bit. Fishermen show less and less respect for the area every year. People are trying to sleep!!! At 2AM Keep your voice down, don’t slam car doors 15 times and don’t treat the place like your personal toilet or dumpster! But, I digress.
Again, I don’t know much about the inner workings of the whole thing but this is what I believe to be the case as far as the ACOE goes. Feel free to correct me if I’m wrong.