Nice idea, I'm editing the Thunderstones again soon, but they'll still fit into this series you have here.
My hat's off to you, sir, for this clever twist on two separate posts. Sound has always been a fascinating medium to me, and discord can be just as potent as harmony. As an exercise, how would you feel about a joint effort to expand both subs? I will consider your reef and add at least one idea, in the hopes that you will do the same for my woods.
Agitato Dragons -
Agitato dragons bear a strong resemblance to sea horses, and are considered bad luck by the locals. Like magpies of the sea, these palm-sized water-dragons spend their time scouring Thunder Reef for unguarded thunder jewels to add to their watery hoards. Often seen carrying (or dragging) a jewel in its long, prehensile tail, these critters cause no end of trouble for divers and sailors alike. For one, the silly creatures startle easily -- any unexpected noise (of which there are many), forbidding entity (ship, diver, predator), or large shadow (even their own!) will cause them to drop the jewel to the sea floor with a resounding boom. As if this weren't bad enough, the tiny pests can build up a dangerous cache of thunder jewels that can stun wildlife within a mile-wide radius, and even sink small vessels if allowed to go off. For this reason, sea merchants who must pass through Thunder Reef regularly will hire brave (or deaf) souls to seek out these hidden caches and disarm them.
racket gulls
gulls that when startled or when mating give of such a noise that any creature in half mile radi will go cover there ears in pian
Lifeforms (Fauna) (Water)