Palaemon

Palaemon (Παλαίμων in Ancient Greek) is the god of sharks and harbors in ancient Greek myths.

History
A sea divinity in Greek mythology, analogue to the Roman Portumnus, the tutelary deity of ports and shores. Under the name Melicertes he had been a child of Ino and Athmas. Ino had nursed Dionysus, one of Zeus' many illegitimate children, and jelous Hera had driven Athmas mad, so that he pursued his wife with intent to kill her. Carrying her child, she leaped into the sea, where both of them became minor dieties-he thereafter called Palaemon and she Leucothea. He was usually portrayed riding on a dolphin and was invoked as a savior from shipwreck. The Isthman Games were celebrated in his honor.

The Last Olympian
Poseidon mentions that Delphin is supposed to send Palaemon and his legion of sharks to attack Oceanus' monsters at the western frontline.

Debated Species
It is implied that Palaemon is the god of Sharks, as he has a "legion of sharks" at his disposal. The people of Greece also thought of him as the god of harbors, but he may also be the god of Sharks and Harbors.