Thanks, Whibla. I don't think it changed, rather was forgotten: The area is now just like Silithus - there are not specific coastal fish allocated, so all parts of the zone default to inland fish.
I'm unsure of the history of Winterspring, but from memory, pre-Cataclysm the coastal area was all zoned as The Great Sea - a separate zone, not part of Winterspring. That's different from now, which zones the water as Winterspring, then a sub-zone called the Great Sea. Without being told otherwise, the sub-zone inherits from Winterspring, and has no connection to the Great Sea parent zone.
There is still a small part of the original Great Sea zone on the border between Winterspring and Darkshore (roughly north of Moonglade), containing Raw Rockscale Cod and Raw Spotted Yellowtail.