As per web site
"1. The visiting season on the Rockefeller Wildlife Refuge will extend from March 1st to December 1st throughout the Refuge except those restricted areas designated to prohibit interference with research and management activities. Use of Humble Canal; Joseph Harbor Bayou; Headquarters Canal; East End Road and Locks; Union Producing Canal; Deep Lake; East End Boundary Canal; and Rollover Bayou shall be year round. In addition to this access, sport fishermen shall be permitted to enter the Refuge from the Gulf side in Pigeon Bayou, Big Constance Bayou, and Little Constance Bayou. Access through these bayous will be permitted only as far inland as the existing water control structures. The remainder of the Refuge shall be restricted during the winter months and will be closed to all trespassing."
"Approximately 106 miles of canals are available to the public for recreational fishing during the spring, summer, and fall. Around 40% of these canals contain fresh to periodically brackish waters. During the winter months many of these fishing canals are closed, as sections of the refuge are closed to limit disturbance to wintering waterfowl. Around 40 miles of canal remain open year round."
http://www.wlf.louisiana.gov/rockefe...or-regulations
Now thats not really definitive but the launch to the gulf is about 7 miles. So I guess there is another 33 miles of canal that stay open year round. Sorry about the last 20 years.