Massive swarms of lion's mane jellyfish, some with tentacles extending up to 120 feet, are currently inundating beaches along the New England coast, prompting urgent warnings from officials for the public to avoid contact with the creatures. The jellyfish have been observed in large numbers from the North Shore of Massachusetts down to Cape Cod and Nantucket, with some sightings reported as far north as Maine.
Great Marsh Kayak Tours in Eastham, Massachusetts, reported thousands of lion's mane jellyfish being swept into marshlands with the tides. The sting from these jellyfish can deliver a significant neurotoxic dose, causing a sharp, burning sensation. Symptoms can escalate within an hour to include red welts, itching, and potentially muscle cramps, headaches, or nausea.
The town of Beverly, Massachusetts, last week advised residents and visitors to keep children and pets away from stranded jellyfish and to avoid touching the creatures or their detached tentacles, even if they appear dead. The jellyfish's sting can remain potent for up to 25 days after the creature has died.
Marine experts attribute the surge in lion's mane jellyfish to a combination of factors including warming ocean temperatures, prevailing wind and tidal currents, an abundance of food sources, and sheltered coastal waters that provide favorable conditions for the jellyfish to thrive before being washed ashore.
This marks the largest influx of lion's mane jellyfish in the region since 2020, with unusually high numbers washing ashore since June in communities such as Scituate, Marshfield, Hull, and Manchester-by-the-Sea. The Boston Center for Youth & Families (BCYF) stated that while beach operations remain open, visitors should remain alert and follow instructions from lifeguards and staff. They urged anyone experiencing a jellyfish sting or requiring assistance to notify a lifeguard or staff member immediately.
The unusually warm start to the summer is believed to be contributing to the jellyfish bloom. According to NOAA's National Weather Service, the average temperature in June for the region was approximately 69.2°F, about six degrees above normal and the warmest June recorded in Marblehead since 2001.
Experts advise that jellyfish stings should be rinsed with seawater, any attached tentacles removed, and medical attention sought if symptoms become severe. While most stings are painful rather than life-threatening, some individuals may experience serious allergic reactions.