When Paul A. X. Bologna heard that a local fisherman had brought a dime-size jellyfish to a New Jersey aquarium, he had a hunch that it might be a Gonionemus vertens, or clinging jellyfish.
So Dr. Bologna, a biologist and ecologist at Montclair State University, brought the animal back to his lab. There scientists extracted, analyzed and sequenced its DNA, and determined that it was indeed the clinging jellyfish, spotted in New Jersey for the first time.
While he was testing the DNA, he heard that a swimmer had been stung in the Shrewsbury River and that more jellyfish had been found in a third location, raising the prospect that there could be a sizable population.
“I’ve worked in eelgrass beds,” the animals’ preferred habitat, “for about 15 years, and I’ve never seen them,” Dr. Bologna said. “But they’re so small, maybe I just overlooked them.”
While these particular jellyfish mostly live in the Pacific Ocean, they have been found in the Atlantic Ocean since 1894, when they were discovered near Woods Hole, Mass., according to Mary Carman, an ecologist and researcher at the Woods Hole Oceanographic Institution.
ADVERTISEMENT
The population has fluctuated over time, Dr. Carman said, possibly after a “wasting disease” infected the local eelgrass population, causing much of the grass to die off and leaving the clinging jellyfish without enough habitat.
But Dr. Carman, who has studied these jellyfish since the first sting on the East Coast was reported in 1990, said they had never totally disappeared from the water around New England.
It was only after 1990 that they popped up regularly, leading Dr. Carman to believe that a second wave of jellyfish was introduced to this part of the world, this one with a higher level of toxicity than the first population.
Dr. Carman and Dr. Bologna don’t have a definitive answer to how the jellyfish got to the East Coast in first place. Maybe they arrived in the water used for ships’ ballasts, or as polyps attached to barnacles on ships’ hulls; in shellfish imports, or perhaps they drifted across the Arctic Ocean.
Dr. Carman said that clinging jellyfish from Japan and Russia were known to have powerful stings, but that those from the northeast Pacific — California and elsewhere — were relatively harmless.
Toxic or not, New Jersey is virgin territory for the animal, which prefers relatively sheltered water, unmoved by winds, wave and tides, with plenty of eelgrass.
Dr. Carman said they are unlikely to be in places where most people swim: open coastline, sandy beaches, places with waves. “Not very many people choose to swim in eelgrass,” she said.
But some people cannot avoid it: Annette Govindarajan, a research associate at Woods Hole who works with Dr. Carman, said most of the people who get hurt are eelgrass researchers, including Dr. Carman, who was stung on the lip in 2013 while looking for clinging jellyfish in eelgrass.
She described the pain as “like being stabbed with five hypodermic needles at once.”
Dr. Carman and Dr. Govindarajan, who are among a relatively small number of jellyfish researchers, said there were no definitive explanations for seemingly growing jellyfish populations and the spread of many species beyond their traditional habitats.
“Jellyfish blooms seem to be enabled by warmer temperatures,” Dr. Carman said. But beyond that, one of their big research questions is whether climate change has enabled the spread of this and other species of jellyfish.
Some effects of human activity, such as ocean acidification, could also have an impact on jellyfish habitats and populations, but Dr. Govindarajan said that remains a mystery. However, both researchers said that overfishing of populations that feed on jellyfish was not the cause of range expansion or of population growth in this case.
While most recreational swimmers at beaches in New Jersey and northward are unlikely to get stung by this particular ocean creature, all of the scientists stressed that its sting can be particularly painful, which is why appearances often make the news.
“There are many different reactions to the sting,” Dr. Carman said. “But it was so painful that I won’t forget it anytime soon.”
No comments:
Post a Comment