Beached Sea Creatures are large, decaying corpses of threshadons, along the western coast of Darkshore.
It's unknown what type of creature might have killed them, before they beached themselves.
Gwennyth Bly'Leggonde, in Auberdine, is interested in the remains of these creatures on behalf of the Temple of the Moon in Darnassus.
[Sea Creature Bones] is needed from one of these creatures for the quest  Washed Ashore
The quest Washed Ashore must be completed, before these quests become available.
Beached Sea Creature locations in Darkshore