A 6-year-old New Jersey girl was hospitalized after developing severe symptoms following a swim in a local river.
Experts later suspected an invasive clinging jellyfish, a species known to inhabit parts of the state's coastal waters.
The incident has drawn attention to the potential health risks associated with accidental exposure to the species.
Scientists are monitoring clinging jellyfish activity as summer recreation increases along the New Jersey coast.
A six-year-old girl from New Jersey was hospitalized after suffering a painful sting believed to have been caused by an invasive clinging jellyfish, drawing attention to the presence of the species in local waterways during the summer swimming season.
Amelia Colvin, 6, was swimming in the Metedeconk River in Ocean County, New Jersey, on June 7 when she suddenly emerged from the water crying out in pain. Her family could not immediately determine what had caused the reaction because no obvious injury or sting marks were visible at the time.
Within hours, Amelia developed a rash, bruising, and swelling on her chest. Despite receiving over-the-counter medications, her symptoms persisted and worsened over the following days, affecting her ability to eat and sleep comfortably.
As Amelia's condition failed to improve, her family sought medical attention. However, the exact cause of her symptoms remained unclear. Concerned about the severity and duration of the pain, her mother researched possible explanations and contacted marine biologist Dr. Paul Bologna of Montclair State University.
After reviewing details of the case, Bologna suggested that Amelia's symptoms were consistent with a sting from a clinging jellyfish, an invasive species known to inhabit parts of New Jersey's coastal waters.
As reported in abc7, Dr. Paul Bologna said,
With other jellyfish, the pain starts, and then subsides. With this one, the pain just keeps building and building and building.Dr. Paul Bologna, Marine Biologist, Montclair State University
Clinging jellyfish (Gonionemus vertens) are small jellyfish originally native to the Pacific Ocean. The species was introduced to the Atlantic coast of North America more than a century ago and is now found in several coastal regions, including parts of New Jersey.
Unlike larger jellyfish that are easily visible, clinging jellyfish are nearly transparent and measure only a few centimeters in diameter. They are commonly found in shallow estuaries, bays, and areas containing eelgrass or dense underwater vegetation, making accidental contact difficult to avoid.1
Clinging jellyfish stings can cause severe pain, skin irritation, rash, redness, swelling, and muscle cramps. Unlike many common jellyfish stings that gradually improve, pain from clinging jellyfish stings may intensify over time. In some cases, individuals may develop more serious systemic symptoms that require medical evaluation and treatment.²
The incident comes as marine scientists track what could be a significant clinging jellyfish season along the New Jersey shoreline.
Scientists at Montclair State University are investigating the life cycle of clinging jellyfish to better understand their reproduction patterns and determine whether colder winter conditions contribute to larger populations, according to NBC 10.
ABC 7 reported that clinging jellyfish are highly sensitive to rising water temperatures, with their numbers declining as waters become warmer during the season.
Although clinging jellyfish are not commonly encountered, researchers have documented periodic population increases in eelgrass habitats along parts of the northeastern U.S. coastline, where the species is most often found.²
The New Jersey Department of Environmental Protection advises people who suspect a clinging jellyfish sting to rinse the affected area with seawater rather than freshwater. Any visible tentacles should be removed carefully using gloves or a thick towel to avoid further exposure.
Individuals experiencing persistent pain, worsening symptoms, or signs of a severe reaction should seek medical attention promptly.
Treatment recommendations may vary depending on the jellyfish species involved. Local experts recommend vinegar and heat therapy for suspected clinging jellyfish exposure, while general jellyfish first aid guidance may differ.
Speaking to News 12, Dr. Bologna said that Sting No More spray is among the most effective options for treating clinging jellyfish stings at home. He also noted that white vinegar may help by preventing any remaining stinging cells from releasing additional venom. He recommended gently cleaning the affected area and applying a hot compress, explaining that heat can help reduce the effects of the venom already injected into the skin.
Amelia has since recovered from the incident. Her case has increased public awareness of clinging jellyfish and the health risks associated with accidental exposure.
Amelia's mother said she hopes her daughter's experience will help raise awareness among other families. Speaking to NBC 10, she emphasized that stings from clinging jellyfish can cause significant pain in young children and urged parents to be aware of the potential risks when children are swimming in affected waters.
Experts encourage swimmers, kayakers, and families using coastal estuaries to remain alert during peak summer months, particularly in areas with dense eelgrass where clinging jellyfish are known to occur.¹
1. New Jersey Department of Environmental Protection. Clinging Jellyfish Fact Sheet. Trenton, NJ: New Jersey Department of Environmental Protection, n.d. Accessed June 18, 2026. https://www.nj.gov/dep/docs/clinging-jellyfish-factsheet.pdf
2. Govindarajan AF, Carman MR, Kintner A, et al. "The Highly Toxic and Cryptogenic Clinging Jellyfish Gonionemus sp. from the Northwestern Atlantic Ocean Likely Originated from the Northwest Pacific Ocean." Biological Invasions 21, no. 4 (2019): 1215-1228. https://doi.org/10.1007/s10530-018-1890-2
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