This large lion's mane jellyfish, and about a half dozen others, were spotted at Bristol's Rockwell Park docks on Friday, April 25.

EAST BAY — The arrival of spring has brought the return of giant venomous jellyfish to Rhode Island waters. Lion's mane jellyfish, the largest known species of jellyfish, are becoming a common sight in Narragansett Bay.

The jellies — like this one, spotted Friday at Bristol's Rockwell Park docks — are confined to cold northern waters, and those who spend time in and around the water are advised to give them a wide berth. Their tentacles, which contain stinging cells designed to incapacitate prey, can cause severe burns and stings.

The jellies have been on biologists' radar screen in Narragansett Bay for several weeks, and last Friday the state Department of Environmental Management issued a warning after a large number of them washed up on Barrington Beach.

Though the specimen shown here is large — its body measured about a foot wide, with four-foot tentacles — it's nothing compared to the largest lion's mane ever recorded. That specimen, which washed up on a Massachusetts beach in 1870, had a body seven feet wide, with 120-foot tentacles.

By Ted Hayes

thayes@eastbaynewspapers.com