This book is on pre-order until release date of August 27 and book delivery arrives.
 
Sails and Sirens by Cynthia Brubaker:
 
Love grows with the tide–and can destroy like a tidal wave.

The Seven Kingdoms are under threat. Sea Hunters, descendants of Pirates, are slaughtering sirens and sea creatures alike. Siren Princess Eliana Leilani of Cerulia is tasked with going to the surface with her little sister, Elara, in an attempt to infiltrate the college campus, where the suspected Hunters dwell. Little does Eliana know that uncovering the Sea Hunters responsible for the attacks on her people would change everything she’s ever known, both about her world and herself.

Will Sawyer is a ruthless Sea Hunter, fighting alongside his father and younger brother, Aidan, to protect unsuspecting humans from the wrath of supernatural entities. He holds a dark grudge against sirens–they killed his grandfather in cold blood. Hunting and sailing are his only sources of solace–until he meets Eliana. He is instantly beguiled by her, tumbling head over heels, with disastrous consequences.

Tensions rise when the Siren Kingdoms and Hunter Association encounter an even larger threat than they can handle. Family bonds will be tested, worldviews will be challenged, and love will prove to be an unbreakable force–or used as a weapon for revenge.