There are several species of jellyfish found in the USA, and the most common ones vary depending on the region:

• In the Puget Sound and off the coast of Oregon, moon jellies are more common in the summer season.
• In Florida and Hawaii, subtropical jellyfish are more prevalent, and box jellyfish show up after every full moon in Hawaii.
• Cannonball jellyfish are the most common jellyfish in South Carolina waters during the summer and fall, particularly in Myrtle Beach.

It is worth noting that there is also a species of freshwater jellyfish called Craspedacusta sowerbyi, which is found in lakes and ponds across the USA. This species is not harmful to humans and is most easily identified when it takes the form of a small, bell-shaped jellyfish, known as a hydromedusa.

The most popular jellyfish in the USA vary depending on the region and the time of year. Moon jellies, subtropical jellyfish, box jellyfish, and cannonball jellyfish are some of the most common species found in different parts of the country.

Most Dangerous Jellyfish in the US

The most dangerous jellyfish in the US is the box jellyfish, also known as the sea wasp. The box jellyfish is considered the deadliest jellyfish in the world, with venomous tentacles that can cause severe pain, paralysis, and even death. The venom of the box jellyfish is one of the most potent in the world, containing toxins that attack the heart, nervous system, and skin cells, causing intense reactions. The sea wasp jellyfish has the ability to kill up to 60 people. The box jellyfish is found primarily in the waters around Australia, but it has also been reported in the Gulf of Mexico and the Atlantic coast of the US.

Other dangerous jellyfish species in the world include the Irukandji jellyfish, which is the most venomous of its kind and is found in the waters around Australia. The Portuguese man o’ war, which is not a true jellyfish but a siphonophore, is also considered dangerous due to its venomous tentacles.

Symptoms of a Jellyfish Sting

Jellyfish stings can cause instant pain and inflamed marks on the skin, and in some cases, they can cause more whole-body illness. The symptoms of jellyfish stings depend on the type of jellyfish that caused the sting. If the sting is minor, the person may feel slight pain, itching, burning, or throbbing. A jellyfish sting may look like a rash with red, purple, or brown patches. More severe symptoms of jellyfish stings include difficulty breathing, chest pain, muscle cramps, skin blisters, numbness or tingling, nausea or vomiting, difficulty swallowing, abdominal pain, and excessive sweating. In rare cases, jellyfish stings can be life-threatening.

It is important to seek medical help right away if the person experiences severe symptoms or if the sting covers a large area of the body. In most cases, jellyfish stings get better over a few days or weeks with home treatment. Home treatment includes rinsing the affected area with vinegar, removing tentacles with tweezers, soaking the affected area in hot water, taking pain relievers, and applying topical creams or ointments to relieve itching and pain

Most Dangerous Jellyfish Species by States (USA)

Please note that this table is not exhaustive and the presence of dangerous jellyfish may vary depending on the season, water temperature, and other factors. Always exercise caution when swimming in the ocean and check with local authorities about the presence of jellyfish in the area.