Although they're not especially missed, there have been fewer jellyfish in Long Island Sound this summer, and many say cool water temperatures and the abnormal amount of rain is to blame -- or thank.

David Simpson, director of marine fisheries for the state Department of Environmental Protection, said although he didn't have any firm numbers, he has heard that the stinging lion's mane variety of jellyfish are "far and few between" this summer.

"It's certainly good for the swimmers," Simpson said of the dearth of stinging critters in the Sound's waters.

It could also prove to be very good for participants in Saturday's Swim Across the Sound from Port Jefferson, N.Y. to Bridgeport's Captain's Cove. In past crossings, jellyfish have stung swimmers, particularly in the middle of the Sound.

Jellyfish aren't actually fish. Rather, they belong to the phylum Cnidaria, a structurally simple group of marine animals that includes sea anemones and corals. The creatures are 95 percent water and have no brain, heart, blood, lungs or gills. They feast on a variety of zooplankton, comb jellies and, occasionally, other jellyfish. Though jellyfish don't attack humans, they have been known to sting swimmers and other beach denizens that come into contact with them. The severity of the sting depends on a variety of factors, including the species of jellyfish, and the sensitivity of the victim. Most jellyfish stings cause relatively minor pain and irritation.

Simpson said several factors could be causing the decline in stinging jellyfish, including this summer's cool weather and heavy rainfall. "The water temperatures have been below average for this time of year," he said. Though the temperature change is small -- maybe a degree cooler than last year -- it can have an impact on the jellyfish population, Simpson said. He did add that there has been an increase in the relatively harmless, non-stinging ctenophore variety of jellyfish, but didn't know why.

Megan Priede, medical quarantine aquarist for Mystic Aquarium and Institute for exploration, agreed that lower temperatures trickle down to the jellyfish world. Though most varieties of jellyfish are capable of surviving a variety of water temperature, many of the creatures they eat aren't as hearty. "If those [organisms] aren't surviving, then the jellyfish will not survive."

But not all think the chilly temperatures are responsible for the plunge in jellyfish numbers. Joe Schnierlein, manager of professional development at the Maritime Aquarium in Norwalk, blames the rain. "The cool weather might have something to do with it," he said. "but I think it's the fresh water runoff."

According to Schnierlein, jellyfish were spotted as early as April of this year, but since then, the increased amount of rain, which is freshwater, as opposed to the salt water they are used to, have reduced their numbers.

Whatever the reason for the small jellyfish population, the decreased likelihood of stings from the critters should put a smile on the face of many human swimmers, including those participating in the Swim Across the Sound, sponsored by St. Vincent's Medical Center Foundation in Bridgeport.

During last year's event, Bill Szturma, a boat escort captain for the swim, said many swimmers were stung while in the middle of their journey across the Sound, including the swimmer following his boat. The Stratford resident said he has never seen such a large amount of jellyfish in his 30 years of boating.

Szturma said the EMTs on his boat gave the female swimmer oxygen and an emergency blanket to keep the heat in. She was also wiped down with a special wipe, which pulls the venom away from the skin to help ease the sting.

"Because I experienced that with my particular swimmer," Szturma said, "I will now be able to recognize it better and act faster in terms of requesting medical help."

Maybe this summer, the Sound swimmers will not need as much help.