Perhaps you’ve seen their umbrella-shaped bells and trailing tentacles drifting by, or noticed their translucent bodies washed ashore on a beach — jellyfish, both native and fledgling, are passing through Vineyard waters.
It’s “very common” in late August and early September to see swarms, or “a smack,” of jellyfish off Martha’s Vineyard coasts, according to Woods Hole Oceanographic Institute researcher Mary Carman. Why? “We have fairly healthy coastal waters,” she said. “In my opinion, it’s a good thing.”
According to Carman, the large jellyfish we’re likely seeing are Atlantic sea nettles (Chrysaora quinquecirrha) or lion’s mane (Cyanea capillata). Sea nettles are usually white in color, but can also appear light pink, and lion’s mane are generally a purple-pink. Both are “very large” and native to the area, according to Carman.
Jellyfish eat zooplankton, excess nitrogen pollution, algae, worms, and sometimes other jellies, according to Carman. While some believe we’re having these worldwide ”jelly blooms” due to a warming climate, Carman and many other scientists agree it’s simply a sign of a good ecosystem. “It’s very common for there to be an abundance of jellies every 20 to 25 years,” she said. “We’re in a cycle now where conditions are favorable for them to thrive.”
Depending on sensitivity, sea nettle stings generally last 45 minutes to an hour, while lion’s mane stings often go undetected. “But it’s like a bee allergy,” Carman said. “Some people are more allergic than others … I’ve never heard of anyone going to the hospital over it.”
Portugese man-of-war (Physalia physalis) are a different story. Often spotted on or off Aquinnah shores, man-of-wars are Island transplants, often windblown here from Florida and Central America via the Gulf Stream. “They have these combs that stick up above water, so they are very easily wind-driven,” Carman said. “They like being in open ocean, and are used to high-salinity waters … We usually see them around this time of year, and that will be it.”
A Portugese man-of-war sting is “a lot worse” than a sea nettle sting, Carman said. “You can get a sting from them if you step on one when they’re dead on the beach,” she said. Their stings often leave an elongated red mark, and sometimes result in a visit to the ER. The Martha’s Vineyard Hospital saw two jellyfish stings this season.
“It’s hard to tell exactly what type of jellyfish sting it is, based on just the sting itself,” said Dr. Alamjit Virk, director of the Emergency Department. “However, the most common sting here that can cause symptoms severe enough for an ER visit is the Portuguese man-of-war.”
After a sting, Dr. Virk and Emergency Department nurse manager Mike Spiro recommend vinegar on gauze. “If we think tentacles are still on the skin, we use shaving cream to scrape them off [using a tongue depressor]. You can do this at home as well.”
A sting requires a trip to the ER if an individual has difficulty breathing, trouble swallowing, dizziness, nausea, or hives on the body, according to Spiro and Dr. Virk.
“Two patients is fewer than usual [for a season], but it’s hard to give a ‘typical’ number on how many jellyfish stings we see over a summer,” Dr. Virk said. “It varies greatly.”
Martha’s Vineyard also sees a fair share of Gonionemus vertens, commonly known as the clinging jellyfish. They’re about the size of a quarter, and leave “a nasty sting,” Carman said. Gonionemus are often found in Martha’s Vineyard ponds in June and July, and recently spread to Edgartown Great Pond, according to Carman, who studies Gonionemus and has written five papers on the species.