I have a love hate relationship with WoW fishing, it is much improved from the original vanilla version, but like Archaeology it leaves a lot to be desired. The biggest issue is the time it takes to level. The dailies and the Darkmoon Faire take a huge chunk out of the leveling process but it is still not a level in day type of activity.
Yesterday I received a whisper from a guildy who was combing the beach at Darkmoon Island and stated his bags were full and he was the only person fishing. Now this struck a chord because I had seen the occasion pool of Shipwreck Debris but only really around the pier area. I had never considered the whole coast as an area available for plundering.
I whisked a character out there pretty damn sharpish and discovered lots of pools, mostly with one shot items of sealed crates, so not the best scenario for leveling fishing, but the rewards from the sealed crates are phenomenal (ores, herbs, cloth and thick leather). As with any pool in Cata and Northrend it also contains a very slim chance for collecting a Sea Pony or Sea Turtle.
The area is best for DK's and Shaman due to the Water Walking abilities but there is always alternatives with potions for any class, the reason is that there some pools hidden behind the small islands.
In the end its not the most productive use your time but I did manage to kill 2 birds with one stone.