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Writer's pictureAnna Tattelman

Invasion of the Jellyfish

If you have visited any Massachusetts beaches this summer, you may have come across a sign or lifeguard saying “BEWARE OF JELLYFISH”. A variety of jellyfish have been spotted in New England waters this summer. After months of being stuck at home courtesy of COVID, people were excited to make the most of the summer, which for many means swimming in the ocean.  Interestingly, those ocean bound beach lovers faced another concern. Although it is not unusual for jellyfish to visit New England waters, the increasing number of them is a bit concerning, in particular the dangerous species Portuguese Man O’ War. Talk about putting a sting in the summer!

From Nantucket Sound, across Cape Cod bay and all the way to the Gulf of Maine, large numbers of several jellyfish species have been observed. The most common type of jellyfish in Mass right now is called Lion’s Mane. It is a bright orange color, with long tentacles, and has a painful but not overly dangerous sting. The Provincetown Independent states, “Nichols said some of the jellies he’s seen are up to three feet wide. He hesitated to speculate how long the tentacles would be on a creature of that size.” Chris Doller, a jellyfish specialist  and supervisor of changing exhibits at the New England Aquarium in Boston, says that Lion’s Manes in New England waters normally measure 10 to 12 inches wide. “They typically get bigger as you get colder,” Doller said. Scientists wonder what could be the reasoning behind the invasion of Lion’s mane jellyfish on the New England coastline. It could be as simple as the temperature of the water, but it could also be the Jellyfishes eating sources. Lion’s Mane mostly eat Plankton and fish eggs. Not to mention the poor fish that get tangled in jellyfish's tentacles. They are also known to eat other jellyfish.

This is picture of a Lion's Mane jellyfish!


Another type of jellyfish, Moon Jellies, have always been common in the Cape Cod beaches, and waters of Massachusetts. Most Moon jellies are harmless, in fact, they are actually quite friendly. Some are incapable of stinging, and therefore cannot hurt another living thing. Since Moon jellies are so common in the Cape Cod beaches, and Lion’s Mane feed on other jellyfish, maybe that's where the crazy numbers of jellyfish are coming from!


This is a Moon Jelly on the beach!


A different and much scarier type of Jellyfish, in terms of the real threat it poses, is called the Portuguese Man O'War.  This creature has been known to visit the Cape Cod waters in the summer/fall time. Thankfully it is not nearly as common as Moon Jellies or Lion’s Mane. However, this summer on multiple occasions, as many as ten were observed in one day in Nantucket waters. Portuguese Man O'War jellyfish are extremely dangerous. Even the smallest sting could cause serious problems. This is because the Portuguese Man O’War has an extremely poisonous venom that gets released by its sting. From an article on Cape Cod Times, Dean Geddes wrote, “The highly-venomous Portuguese Man O’ War has joined the Atlantic sea nettle and Lion’s Mane jellyfish in island waters, being spotted in both Nantucket Harbor and Madaket late this summer. 


Here is a photo of the Portuguese Man O'War!



So if you still have plans to visit the coast, with what’s left of the summer, keep your eye out for the large, bright orange creatures known as Lion’s Mane jellyfish.  They are not aggressive or dangerous but if you happen to swim into their tentacles, you will get stung.  More importantly, be sure to avoid the blue colored Man O’ War that can be seen above water. Also make sure to give them a lot of room since their green tentacles can grow thirty feet long and should be considered extremely dangerous. Happy swimming!


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