Catch of a Lifetime by Judi Fennell

The Mer people are supposed to stay far away from humans. But Angel Tritone—technically a mermaid princess—is obsessed with them. A scientist and sociologist in her own world, she’s determined to convince humans to stop polluting her ocean home. But when a shark attack forces her to escape to a boat, she discovers just how enchanting humans can be. Especially one particularly sexy specimen and his delightful six-year-old son.
After growing up in a family of carnies and cons, all Logan Harding wants is a normal life. Ordinary. Boring even. But the naked woman he finds sleeping on his boat is anything but ordinary. The executive of a Florida sea park already has his hands full learning to be a father to the son he never knew he had. The last thing he needs in his life is a deliciously tempting but obviously crazy woman, especially one claiming to have amnesia.
With her tail dried into perfect, oh-so-shapely human-looking legs, and the relationship heating up, Logan has no idea of Angel’s true identity. Her presence eases his relationship with his newfound son, but the secret Angel’s keeping could endanger them all. When he discovers the truth, will Logan throw her back in the sea or realize he may have made the catch of a lifetime?