Mini Jellies In Sedge Lot Pond Pack A Mega Punch

By: Brian Kehrl
Published: 07/30/10

A swarm of little jellyfish stung two researchers in Sedge Lot Pond near South Cape Beach last Thursday, sending them to the hospital with severe muscle cramps, chest tightness, and swollen throats.

The bell-shaped jellyfish, each smaller than a golf ball, were identified by staff at Waquoit Bay National Estuarine Research Reserve as a species called Gonionemus vertens, also known as GV, clinging jellyfish, orange-striped jellyfish, or angled hydromedusa.

“There is no real common name for them. It is just nasty jellyfish. Whatever you want to call it, it is extremely potent,” said Richard H. York, Mashpee shellfish constable.

The jellyfish are known to be in the shallow ponds around Waquoit Bay, like Jehu, Hamblin, and Sedge Lot in Mashpee and Tim’s Pond on Washburn Island in the Falmouth side of the bay, according to Edward Enos, superintendent of aquatic resources division at the Marine Biological Laboratory in Woods Hole.

“This isn’t like great whites swimming by, if you know what I mean. But it is something you’d want to be aware of,” Mr. Enos said.

It also is not anything like the giant, lion’s mane jellyfish that reportedly stung upward of 150 people on the New Hampshire coast last week. “It seems like attack of the jellyfish, but these are two entirely different animals,” he said. “Gonionemus are small; they are up in quiet areas, unlike the lion’s mane, which get quite big. The lion’s mane are found south and north of us, are in Vineyard Sound, Cape Cod Bay, Buzzards Bay. The real big ones are usually found out in the open water.”

Alison Leschen, director of WBNERR, said this week that she has found scientific reports of the Gonionemus vertens living around Cape Cod, has heard several anecdotal accounts of them being toxic here, but has not found scientific literature indicating that they are toxic in this area.

Christopher Weidman, research director at WBNERR, wrote in an e-mail, “As mentioned, what I’m finding or not finding is any reference to this species being toxic in the New England or US East Coast (only Sea of Japan and Kamchatka and perhaps Katchamak Bay, AK (all Pacific locales)—in fact, it is reported to be non-toxic most everywhere else—and for this reason there should be some reportage of this both in the scientific literature as well as for regional toxicology folks. This could be an ER issue for the coastal region during summer.”

Mr. Enos, who for more than four decades has been collecting marine species around the area for research by scientists at MBL, said that until a few years ago, he only knew them to be in salt ponds over on Martha’s Vineyard, where he would often go to collect them for research.

He discovered their presence in Jehu Pond when two of MBL field workers were stung and had to be taken to the hospital.

Mr. Enos said he would not be surprised if the jellyfish also live in other, similar environments, like up in the Bass River in Yarmouth or up in Popponesset Bay, though they have never been documented there. He said they do not like areas with heavy disturbances, like open bays with larger tides, bigger waves, and boat traffic.

According to a report on the species from the United States Geologic Survey, the jellyfish are thought to be native to the Pacific Ocean but were transported to the Atlantic in ship ballast water, clinging onto oyster shells.

The species was first documented in 1862 by Alexander E. Agassiz, the son of one of the founders of MBL and a prominent marine scientist.

GV are distinguishable by a cross found in the middle of the top of the bell and sharp bends at the end of their tentacles.
The lion’s mane is also typically larger when found in this area, more like six or eight inches rather than one or two, Mr. York said.

The bell-shaped body of GV is transparent, usually clear or with a slight greenish tint, according to a research paper on the species in a Russian marine biology journal, provided by Ms. Leschen.

GV fold themselves around blades of eelgrass or other aquatic plants, waiting for prey. When they notice something, they pounce and sting their prey before eating it.

They swim fast, pulsing through the water, Mr. Enos said.

“It is very similar to being stung by a wasp,” he said.

The two scientists in Sedge Lot last week, from the National Park Service and the state Division of Marine Fisheries, were wading the shallow pond while researching eel grass, according to Ms. Leschen. One of them bent down to insert a screw into an eelgrass bed when a group of the jellyfish swarmed out and stung them both at almost the same time.

Within 30 seconds they were experiencing stinging and tingling all over their bodies, followed by strong muscle cramps, chest tightness, and their throats closing up, almost identical initial reactions, Ms. Leschen said.

They were with two other researchers who helped them to a car, she said. They were headed to the emergency room but stopped at the Mashpee Fire Station en route for treatment and faster transportation. They were taken to Falmouth Hospital and treated with an antihistamine, she said.

One of the researchers was better the next day, except for random tingling sensations, she said. The other, though, came down with a fever and flu-like symptoms that lasted about 24 hours.

Ms. Leschen said she has contacted the hospital, where the doctors were reportedly not familiar with a local jellyfish that causes the reaction the researchers were having, to warn them of the presence of the highly toxic jellyfish and the possibility that others might be coming in with similar symptoms.

Mr. York said one useful treatment for jellyfish stings, if applied immediately after the sting, is powdered meat tenderizer with papain mixed into a paste with saltwater. “You need to get it on right away. Ten minutes is too late,” he said.