Marine worms’ ‘fascinating phenomenon’ make annual appearance in South Carolina waters

A swarm of marine worms has made its annual return at a harbor in Charleston, South Carolina.

The state’s department of natural resources released footage of the hooked-jaw worms on April 14, showing the species in a frenzy by the harbor.

"Nothing says spring on the coast like a frenzy of marine worms," the department wrote on Facebook, adding, "You may not want to go swimming," due to the worms having a set of hooked jaws.

Environmental officials said the worms, also known as clamworms, usually stay on the seafloor, but morph into reproductive forms called "epitokes" in the spring.

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"This fascinating phenomenon occurs every year at our marine headquarters in Charleston and is often followed by hungry throngs of fish and birds along the marsh edge," they added.

The department said the worms are not dangerous. They are, however, part of the aquatic food chain that feeds fish and other marine species.

The creatures die once they reproduce. 

This story was reported from Los Angeles.