This Summer Brings Unprecedented Jellyfish on Delaware Beaches

• Significant increase in jellyfish stings on Delaware beaches
• Rescuers use vinegar to alleviate sting pain
• Rising water temperatures contribute to increased jellyfish populations

Lewes, Delaware. This summer, the number of jellyfish on the shores of Delaware has risen sharply, leading to an increase in jellyfish sting incidents. According to data from the state beach patrol, in July, there were reported four times more stings than in 2024.

Among the jellyfish commonly encountered in the summer waters of Delaware are lion’s mane jellyfish, moon jellyfish, and sea nettles. The increase in jellyfish numbers has become a common occurrence from Maine to Florida due to rising water temperatures, which promote their growth.

On a typical year, Delaware beaches report only a few jellyfish sting incidents. However, this year, in the Fenwick Island state park, there was a record of 92 stings in one day. Three lifeguards had to call for medical assistance after swimming in waters where jellyfish were present.

The beach patrol service in Delaware began tracking jellyfish sting incidents this year due to their rising numbers. In 2024, 295 incidents were recorded on Lewes beach, and by 2025, it is expected to exceed 1200.

Lifeguards have started using vinegar to treat jellyfish stings. However, some studies suggest that using vinegar may lead to the release of microscopic nematocysts, which can cause further irritation. Experts recommend using a different food acid instead.

While jellyfish stings from lion’s mane jellyfish and sea nettles usually cause only mild irritation, in severe cases of allergic reactions, lifeguards may provide first aid.

The increase in jellyfish numbers may negatively impact ecosystems and marine industries, as jellyfish compete for food with fish. Many beaches across the region are also reporting an increase in jellyfish sting incidents.

Scientific research on jellyfish is limited, but specialists are looking forward to further studies to improve safety from stings and evaluate ecological consequences.

Tags: USA/Ecology