Jellyfish: Phantoms of the Ocean

Forrest M. Mims III

Folks who enjoy salt water swimming, fishing or kayaking have probably had an encounter with a jellyfish or two. Many of these exotic creatures, which are fish only in name, are equipped with countless stinging cells along their tentacles.

When a stinging cell is triggered by touch or a change in environment, a dart coiled inside is released with tremendous force. The dart may then inject a neurotoxin into whatever it strikes.

A single jellyfish stinging cell contains considerably less venom than a wasp sting, but jellyfish carry lots of darts. When a swimmer inadvertently mixes up with a jellyfish, the animal’s tentacles may wrap around arms, legs or even an entire body. The result can be many hundreds of separate dart stings and considerable pain.

A jellyfish sting causes an intense burning or stinging sensation. Various remedies have been suggested, including vinegar, isopropyl alcohol and meat tenderizer. However, some such remedies have been shown to stimulate more stinging cells to release their darts.

Emergency medical treatment might be necessary for people who experience a severe reaction to jellyfish stings.

A variety of jellyfish inhabit the waters off Padre Island. Probably the best known is the Portuguese man-of-war (Physalia physalis). These creatures are a colony of several different animals suspended from a gas-filled sac that floats on the surface and serves as a sail. Their tentacles can exceed 45 meters (150 feet) in length, and their toxin is nearly as potent as cobra venom.

The cannonball jellyfish (Stomolophus meleagrisis) among the most common along the Gulf Coast. These creatures appear like translucent balls around 25 cm (10 inches) or so in diameter. While they are not as venomous as other jellies, their numbers can cause major problems for shrimpers when they clog their nets. A study reported by Auburn University found that one swarm of cannonball jellies passing through Port Aransas, Texas, numbered some 2 million per hour!

The Texas State Aquarium at Corpus Christi has a wonderful display of living jellyfish that is well worth a visit. Various species of jellyfish inhabit separate aquariums that feature hidden lights that illuminate these exotic animals of the sea.

While watching these graceful creatures as they swim up, down and around their tanks, one can only wonder how those stinging cells that are supposedly triggered by contact don’t fire when tentacles cross one another and other jellyfish.

For details about visiting the Texas State Aquarium, see their web site.

Forrest M. Mims III and his science are featured online at www.forrestmims.org and www.sunandsky.org/.