Commanding the Tides — Michelle M. Pillow

Paranormal Underwater Shapeshifter Romance Lords of the Abyss Book Two Cassandra Nevin has come to the ocean to live out her days on a boat with a bunch of scientists who don't know she's terminally ill-or that she's not even a scientist. When something from the depths of the abyss attacks their ship, leaving her to drown, she knows it's her time. But then the unimaginable happens-she lives. Iason the Hunter doesn't understand why the woman he's trying to save from death seems insistent he save anyone but her. Duty bound to try and rescue whoever he can; he takes the woman into Deep Ocean, to his home beneath the waves. But it would seem a watery grave wasn't the only thing threatening his new charge's life. To try and save her from her illness would mean possible disgrace and being banned from ever swimming in the ocean again. But what else can he do? From the first moment he saw her, she had command over his heart.