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Scientists investigate global spread of stinging jellyfish



Get it off of me! Get it off of me!” shrieked Mary Carman, a marine ecologist at Woods Hole Oceanographic Institution (WHOI) as she flailed knee deep in the bath-like water of Farm Pond on Martha’s Vineyard.

She was observing tunicates (also known as sea squirts) in the quiet coastal pond, garbed in a full wetsuit and snorkeling gear as she hovered through the shallow grassy water. She was well covered except for parts of her face, including her lips which became a landing spot for a clinging, stinging jelly.

“The sting was one of the most painful things I’ve experienced in my life—I liken it to being injected by five hypodermic needles simultaneously,” she said.

Despite the ensuing pain and “two days of nausea,” Carman has been back in Farm Pond on several occasions. But instead of looking at tunicates, she’s been collecting samples of the toxic jellies, scientifically known as Gonionemus sp. In the past several years, she, along with WHOI biologist Annette Govindarajan and their colleagues, has been tracking these clinging jellyfish which, according to a new study, appear to be expanding throughout the Cape and Islands region.

Conducting research in Farm Pond on Martha's Vineyard in August 2013, WHOI scientist Mary Carman was stung by a clinging jellyfish. She investigated further and found more reports of clinging jellyfish stings in the area. Photo by Dann Blackwood, U.S. Geological Survey, Woods Hole.
Conducting research in Farm Pond on Martha’s Vineyard, WHOI scientist Mary Carman was stung by a clinging jellyfish. (Photo by Dann Blackwood, U.S. Geological Survey, Woods Hole)
In recent years, we’ve started to see these jellies show up in a number of major coastal ponds across the island in addition to Farm Pond,” said Carman, the lead author of the study. “Confirmed locations have included Sengekontacket Pond, Stonewall Pond, and Lake Tashmoo,” said Carman, the lead author of the study. “Now, we’re seeing a new invasion in Edgartown Great Pond, the largest great pond on the island’s south shore.”

Secret hitchhikers

The toxic invader looks like a clear, medium-sized coat button collared with several dozen threadlike tentacles. The tentacles sport adhesive-like pads that allow the animal to stick to eelgrass, seaweeds—and yes, lips too—before emitting venomous neurotoxins that can cause extreme pain, breathing difficulties, and blisters. Their origin is unclear.  The jellyfish were abundant in a few New England locations, including Eel Pond in Woods Hole, Mass. in the late 1800s until about 1930, when they all but disappeared after a slime mold decimated most of the region’s eelgrass. Carman and Govindarajan are unaware of any regional reports of stings during this period, although stings had been reported from the Sea of Japan.

The jellies resurged on Cape Cod in the 1990s, with the first documented sting report occurring in 1990 in Waquoit Bay. The first documented Martha’s Vineyard sting occurred in 2006 and it appears that the population has been expanding there ever since. According to the study, in one of the newly colonized sites (Edgartown Great Pond), jellyfish were clustered in a cove with a public boat ramp, suggesting that transport on boat hulls could be promoting their distribution around the island. “The jellyfish have life cycle stages that can be less than a millimeter in size and that adhere to surfaces, so they could very easily be hitchhiking on boats without being seen,” said Govindarajan.

The study points to another factor possibly contributing to the spread: cloning. This particular species is known to have the ability to make multiple copies of itself during various stages of asexual reproduction. “As we analyzed the sex ratio of our samples, we discovered that all of the jellies collected at Edgartown Great Pond were male,” said Govindarajan. “This is consistent with the possibility that this particular population is clonal, and that asexual reproduction is contributing to their spread. But we need more information on the dynamics of these stages, such as how long they can persist and what factors trigger them to produce jellyfish.

Across the pond

According to the researchers, the toxic jelly outbreak isn’t just a local phenomenon: the animals have been found along the coasts of Russia, Japan, China, the Mediterranean, Argentina, and most recently, along Sweden’s rocky west coast, where just last summer, a number of bathers were stung. That outbreak was documented in another study in which Govindarajan and colleagues from Sweden compared DNA sequences of clinging jellies collected at the site with those found along the US East Coast and other parts of the world, and discovered some genetic similarities.

We found some common genetic variants occurring in disparate locations where stings have been reported,” said Govindarajan. “We’re not sure what’s triggering these toxic outbreaks – multiple factors may be at play, but human-mediated transport of the tiny, cryptic life stages may have a role globally as well as locally.

Björn Källström, a marine biologist at Gothenburg Marine Biological Laboratory and co-author of the study, says underwater photographers have observed clinging jellies in Sweden in the past, but last summer marked the first time that people there reported being stung.

One factor may have been the really hot and dry summer we had last year, which caused water temperatures at the site to surge 3°C above seasonal averages,” he said. “Previous studies have suggested that when ocean temperatures are warmer, clinging jellyfish production is triggered. And when they increase in numbers, more people are likely to encounter and get stung by them.”

Avoiding hot spots

With a host of possible factors at play—anthropogenic transport, warmer ocean temperatures, and the comeback of eelgrass—Govindarajan, Carman, and their international colleagues plan to continue studying the stinging creatures to better understand the intricacies of the spread.

Källström feels that in the near term, the research can help bathers avoid areas where the jellies are likely to disperse.

Climatologist have predicted another hot, dry summer in Sweden, which means that we could see another outbreak over the next few months,” he said. “And this time, we suspect it may spread to other locations along the coast. So, we’ll be developing models to help predict where the jellies may go, so people know which areas to stay away from.”

Govindarajan agrees. “The more we can learn about how they’re expanding and the types of conditions the jellies are thriving in, the more we’ll be able to identify where the hot spots are and educate the public.”

Gonvindarajan says the community can also help the monitoring effort by reporting sightings of clinging jellies to—although she cautions people to be careful, and to not handle the jellies.

For more information about the work of WHOI please visit their website by clicking here.


White Shark Interest Group Podcast #009 – SURVIVING A SHARK ATTACK with DAVE PEARSON



Ninth in an exciting podcast series from Ricardo Lacombe of the White Shark Interest Group.

Episode 9 of the White Shark Interest Group Podcast, Facebook’s’ largest White Shark specific group, covering science, conservation, news, photography, video and debate.

This episode features Melissa speaking with shark attack survivor Dave Pearson, about his experience, the aftermath and trauma for all involved, and the social media comments and victim blaming following an incident or attack.

Dave is the founder of Bite Club, a support group for survivors of attacks and bites, as well as for the families and friends of victims following a tragic incident.

He also established Beyond The Bite, a support organisation serving many purposes for anyone involved in shark attacks, from helping to get surfers back in the water, to covering costs of families who need to travel to the site of a loved ones attack.

This is a MUST LISTEN for all shark advocates as Dave and Melissa discuss how advocates can really help in the aftermath and reporting of an incident, and how shark advocates can become human advocates at the right time it is needed most. A real eye-opener of an episode.

Bite Club can be found on Facebook here:… Beyond The Bite can be found here: and would appreciate ANY donations you could make to help survivors and their families

Click the links below to listen to the podcast series on the following audio channels:

Join the group:



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Ultimate Diving Maldives Offer



7 nights at the Bandos Island Resort & Spa in the Maldives – From £2555 per person

Bandos Island Resort & Spa has already welcomed its first guests to the Maldives since March, with more divers heading off this December trying to escape the chilly UK weather. The Maldives is a dream destination, it offers a range of blue lagoons, deserted islands, a true sense of romance and tranquillity but above all amazing diving.

This destination should be on every diver’s bucket list, especially those with a non-diving partner because there is enough going on to ensure everyone will have a great time. The Maldives are the ultimate island paradise with each one offering dazzling white sandy beaches topped with coconut palm trees and turquoise blue lagoons.

Bandos Island is fully encircled by pearly white beaches, turquoise waters and a never-ending blue sky blessed with abundant sunshine. The house reef at Bandos is considered one of the best in North Male Atoll and the convenient location of Bandos allows divers to choose from over 40 impressive dive sites.

Book 7 nights from £2555. Price includes flights from London, speedboat transfers, 7 nights’ accommodation on an all-inclusive basis and 10 shore dives per person. Single supplement applies.

To enquire or book, visit or give the team a call on 0208 655 6458  and they can give you the lowdown on the destination and diving.

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Sharks Bay Umbi Diving Village is a Bedouin-owned resort with stunning views and a lovely private beach. It is ideal for divers as everything is onsite including the resort's jetty, dive centre and house reef. The warm hospitality makes for a diving holiday like no other. There is an excellent seafood restaurent and beach bar onsite, and with the enormous diversity of the Sharm El Sheikh dive sites and the surrounding areas of the South Sinai, there really is something for every level of diver to enjoy.

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