This is one of the first quests in a small series of naga related quests. You can get this one by speaking to Shindrell Swiftfire in Astranaar. She says:

There is evil lurking on our northwestern coast, known as the Zoram Strand.

It is the resting place of the doomed city of Zoram, destroyed during the Sundering and submerged beneath the seas. It has been lost to the night elves for ages. Lost, and nearly forgotten.

Now, the naga have returned, and for what reason we do not know. But reason matters little; we must slay these fiends and throw them back to the depths!

Return to me when your mission is complete.

Collect 20 Wrathtail Heads
Return to Shindrell Swiftfire

To begin, travel west past the Maestra?s Post to Zoram Strand where you will soon encounter both Wrathtail Sea Witches (level 19-20) and Wrathtail Wave Riders (level 19-20). Kill them and loot their heads. Fortunately the drop rate is close to 100%, so you shouldn?t have to kill that many to get your quest done. While you are here, you should speak to Talen as well, he has another quest for you called The Ancient Statuette. Most characters would be able to solo this one, but watch out for their magic and knockdown attacks. Once you have the 20 heads, return to Shindrell Swiftfire and she will say:

Very well done. Your actions in the Zoram Strand against the naga are commendable.

I know your feat was not easily accomplished, for the strength and guile of the naga is well known to the night elves. We know this, for we share a history with them.

It is a history I do not care to repeat.

Now you?re done here, but if you like, continue with the Ancient Statuette quest and Talen has more quests for you out there.