This quest is part of The Stone of the Tides quest chain.
The water elementals were no doubt summoned by Gazban, the goblin wizard rumored to have discovered the Stone of the Tides. As you may know, the Stone of the Tides curses its bearer, causing him to fade in and out of existence...
Perhaps we can find a way to counteract the curse. We can have a mage of Dalaran analyze the magical residue of one of the water elemental's bracers. I need you to go back to the island and retrieve a few specimens.
Have you had any luck, <name>?
Hm, I haven't the eye to examine these bracers to see if any of them will be of any use, but I'm sure at least one of them will be able to help. Take them to Dalaran and have a mage look at them.
After all, I can't very well leave Booty Bay just to chat with those tiresome old mages.
Not that I'm worried anyone would try to elbow their way into being the new baron. No one crosses Revilgaz and lives to tell of it.