You find a corpse of a sea turtle that had beached itself on the coast of Darkshore some time ago. It has been scavenged by the murlocs who have encamped themselves around the creature's remains. Still, there appear to be some suitable samples left on the creature's remains that Gwennyth Bly'Leggonde in Auberdine might be able to make use of.
Another discovery for us to research - well done <name>! These remains will be properly studied once they get to Darnassus. Please accept this small honorarium in exchange for the remains you have provided for our study.