The latest sea creature to make an appearance in New Jersey waters is a manatee.

Manatee discovered swimming in the Delaware River off Bordentown (NJ Dept. of Environmental Protection)

Fisherman in Crosswick Creek on the Delaware River near the Interstate 295 bridge in Bordentown were the first to spot the gentle "sea cow" late Tuesday afternoon according to

It joins a list of sea creatures to be sighted in New Jersey waters this summer including sharks, dolphins and dangerous man-o-war jelly fish.

Larry Najna of the New Jersey Division of Fish and Wildlife tells the Courier-Post it is unusual for a manatee to venture north of Delaware since they are warm-water creatures. They were first sighted in New Jersey in 2001.

Anyone coming in contact with the manatee should just leave it alone. Chuck Underwood of the U.S. Fish & Wildlife Service tells, "Just let it do its thing and the animal will likely be just fine on its own.''

Manatees are a slow moving mammal, according to National Geographic, and an endangered species. Their strong tails make them graceful swimmers.