Night scuba divers swarmed by millions of gross, biting bloodworms

Blood worms are a small, carnivorous worm that hides in coral and sand during the day. It can survive with very little oxygen and live under a variety of water conditions. At night, they leave their protective habitat and emerge to feed on small creatures like plankton and tiny shrimp. But they can also bite larger creatures with their highly adapted mouths that contain four flexible and hollow jaws. They inject a mild toxin and their bite can be irritating, even to humans.

Night divers are all too familiar with blood worms and they can suddenly appear in swarms so thick that visibility becomes dangerously poor. Attracted by lights that divers must use, the bloodworms congregate around the light and around any light colored skin that reflects the light. The worms are lightning quick and very agile. They bounce off a diver's mask and face in a very unnerving manner. They even work their way into creases in the scuba masks and become lodged between the mask and face. If a diver stays still more than a few moments after they begin to swarm, he will be pelted with the aggressive creatures on every exposed surface. Even the sound of the worms bouncing off a diver's head is a grotesque experience.

Bloodworms can work their way into a diver's ear and under their wet suit. Although bites are not common, these worms do occasionally chomp on larger creatures such as humans. The venom in their jaws will leave the victim with a noticeable irritation at the site of a bite. Mostly though, they are simply attracted to the light in their search for tiny creatures such as shrimp and plankton.
Adding to the nuisance of the bloodworms, small fish that feed on the worms are also attracted to the lights and they will dart around a scuba diver, often bouncing off ears and faces in their pursuit of a meal.

These divers were enjoying a peaceful dive in the waters of Mexico, filming sea turtles and octopus when they encountered the bloodworms. The water became thick with them and navigating became briefly impossible. The divers dimmed their lights and swam out of the area in order to avoid the swarm.

Night diving has enough challenges without the added problems created by swarming worms!