One of the largest species of jellyfish on the planet: the lion’s mane jellyfish (Cyanea capillata)—have been making unwanted appearances on Massachusetts beaches, the Boston Globe.

The bells of these invertebrates can measure about three feet wide and they can grow tentacles more than 100 feet long. Unfortunately for bathers, they cause very toxic stings, although few cases of human deaths have been known. They are usually found in open ocean ecosystems, in areas of the Pacific, Atlantic and Arctic oceans, as well as the Baltic and North Seas. But for some reason, surprisingly many of them have been observed recently in Massachusetts waters.

“Be on the lookout: Lion’s manes can cause a pretty painful sting! If you see one washed up on the beach or floating in the water, it’s best to admire it from a safe distance,” the New England Aquarium wrote in a social media post.

Jellyfish drift rather than swim. Therefore, a combination of ocean currents and winds may have caused this significant appearance in the Bay State.

“Lion’s mane jellyfish are currently appearing in unusually large numbers off Cape Cod,” reads a social media post from Sandwich Marina – Sandwich Harbormaster on Cape Cod. “While lion’s mane are typically seen from late spring through summer, reports this year began in May, with exceptionally high densities observed in mid-June. Similar blooms have occurred in the past, including in 2020. Experts believe factors such as temperature of available water and food sources may contribute to these increases.

Additionally, the post reminds people not to touch jellyfish, whether they are on the beach or in the water. It’s generally a good idea to stay away from them, as the tentacles can be difficult to spot. If stung, wash the area with warm water and use tweezers to get rid of the tentacles. You can use vinegar to help remove the bite.

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