Shark Bite by Naomi Lucas

Netto was a Cyborg, a protector, and a contracted mercenary. His specialty was with the shallows, the salt water, and the open oceans across the universe. He was also a freak forged from the DNA of a bull shark–blue-grey skin, a body built with power, and a double-set of razor sharp teeth. His nomadic lifestyle changes when his old employer, the Earthian Planetary Exploration Division, offers him his old job back.

Rylie was born and raised on the planet Kepler, on an agri-lot that farmed jewels from the sea. But something was happening to her family’s lots and people were going missing.

When a giant Cyborg shows up in her settlement and commissions her family’s watership, she is forced to follow him out onto the water, into the dangers of the alien deep, far beyond the sight of land.

She feared the Cyborg.
She feared his teeth.
But she feared the monsters in the water more.