You can fish anywhere you want at Kelly Point -- saw guys doing it when I rode a bike through there today. I was also on a dock on the Eastbank today, and there were "No Fishing" signs. There was also a dude casting a massive flyrod right OFF the end of the dock. Pretty sure they have some stupid rule against fishing from the downtown area docks.
Knock yourself out, since it's a stupid rule -- I'm just sayin' it likely isn't legal (I seem to remember hearing about someone complaining about it to the city council). Then again, in those areas, I'm pretty sure the cops have bigger fish to fry than some guy fishing.