By Bill Shields

BOSTON (CBS) – If you’ve walked along just about any Massachusetts beach lately, you may have seen an orange jellyfish in the sand with long tentacles. The lion’s mane jellies are in our waters, which is not all that unusual. But what is eye-popping are the numbers. They are here by the tens-of-thousands.

“The meeting and the confluence of various ocean currents, changing temperatures,” says Anne Smrcina if the Stellwagen Bank Marine Sanctuary.

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Last week, marine photographer Keith Ellenbogen was shooting pictures out on Stellwagen, when he was surrounded. “I saw another, then another, and another,” he said. “And then I realized they were everywhere in the ocean and it was really amazing.”

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Scientists are not sure why the cold-water jellies are here in such numbers. “They are moving sometimes with a particular water mass, sometimes the winds are acting to push some of these water masses in shore, in which point you might see increased number of jellyfish in the near shore environment,” said Dr. Kara Dodge of the NE Aquarium.

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She adds that while the lion’s mane tentacles can inflict nasty stings, there is an upside: the endangered leatherback sea turtles feast on them, which could help the turtles.