Weird venomous sea creatures wash up on South Florida beach

The vivid blue creatures stood out from the broken shells and other debris along the beach in Boca Raton.

As David Marcoe and his girlfriend Jessica Halterman looked for shells along Red Reef Park, they came upon several weird, thumb-sized things with flowery appendages. A little web searching on their phones revealed that they were looking at blue dragon sea slugs, organisms very far from home, with lifestyles as strange as their appearance.

Blue dragon sea slugs are inhabitants of the open ocean, bobbing along the surface, where they catch and kill larger animals, including the Portuguese man-of-war and the similar by-the-wind-sailor. Not only do the blue dragon sea slugs eat these dangerously venomous species, but they take their venom and use it like a captured weapon for defense.

“As they devour the tentacles, they can ingest the stinging capsules without triggering them and store them in these finger-like projections for their own protection,” said Charles Messing, professor at Nova Southeastern University’s Halmos College of Natural Sciences and Oceanography.


Like most animals of their kind, he said, they’re hermaphrodites, having both male and female sex organs.

There were about eight of them on the beach, Marcoe said. Although some of them were squirming, they weren’t moving by the time he and his girlfriend scooped them up with a cup and tried to return them to the ocean. But even if their attempted rescue was unsuccessful, they at least had the experience of seeing such a bizarre mini-sea-monster.

“It was amazing,” he said. “It was really cool. I called Jessica over and said look at this, and she was freaking out, saying how cool it was.”

Messing said their presence on the beach in Boca doesn’t indicate much other than they were unlucky enough to be blown to shore. It’s unlikely there are hordes of these creatures in the water or on the beach, he said.


And while picking them up would not be a great idea, he said, they’re too small to harbor enough venom to deliver the excruciating sting of a Portuguese man-of-war.

“Unless you’re allergic, obviously it’s going to hurt and get inflamed, but it’s not going to be like getting a tentacle of a Portuguese man-of-war wrapped around your leg, he said.

As for trying to save any, he said that’s probably a pointless exercise since they’ll just get washed back onto the beach.

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