Beast of the Bering Sea (2013) on Netflix

Plot summary

Joe and Donna dredge the seabed of the Bering Sea for gold alongside their father, Glenn Hunter. Their digging wakes an ancient species of underwater predators known as sea vampires, winged creatures that feed on blood. The swarm kills Glenn, and the siblings resolve to wipe the creatures out, taking their new deckhand, Owen Powers, into the search. Marine biologist Megan Arthur looks for a reason behind the attacks and works with them. A rival salvage team is maneuvering to take over the family's operation, so the siblings must hold their claim on the water while they go after the beasts.