The patch notes, edited for just fishing:
Timeworn Leather Map: Level 40 fishing holes.
Timeworn Goatskin Map: Level 45 fishing holes.
Timeworn Toadskin Map: Level 50 fishing holes (South Umbral Isles and Rathefrost only)
Timeworn Boarskin Map: Level 50 fishing holes (Reaver Hide and the Tangle only)
Timeworn Peisteskin Map: Level 50 fishing holes (Lake Tahtotl, Parata's Peace, and the North Shards only).
As far as bait, just use the bait that works at that fishing hole; the map can replace any catch randomly, even a mooch.