Waterborn

Molly, a sea siren with dangerous powers, swims to the mainland on behalf of her people. Menaced by an evil supernatural sea monster known as the leviathan, the siren conclave has no choice but to reach out to those on the mainland for help.
Rick is a Navy SEAL, son of Admiral Morrow, who oversees all of the Special Forces soldiers who have paranormal abilities. But Rick's lineage is something different from most. He's an Elemental with vast powers over water. The oceans, rivers, lakes and streams are his domain and all those who dwell there recognize his influence.
When the Admiral sends his son and the siren on an overland dash to Grizzly Cove, they encounter enemies, ambushes and danger. They also meet unexpected allies and new friends. But most surprising is the fierce passion that blooms between them as they work together, discovering how well their abilities complement each other and how well their personalities – and bodies – mesh.
Their ultimate goal is Grizzly Cove – the bear shifter community where the leviathan first reared its ugly tentacles. They will seek the Alpha bear's assistance in safeguarding the small siren community… Goddess grant that they're not too late to save them.