Multi-hued sea anemones turn the coral reef into an underwater garden.

By Suzanne Gerber
Photos By Barbara Shiveley

No, you’re not confused: There are anemones in your garden, and there are sea anemones in the ocean. In fact, the ornately colored sea anemone (uh-NEM-uh-nee) is so called because of the striking resemblance it bears to its colorful terrestrial namesake.

As beautiful and delicate as they may be, anemones are actually highly poisonous predatory creatures. These marine animals, which attach to rocks or corals by an adhesive pedal disc, or foot, spend most of their life laying in wait for unsuspecting fish to swim close enough to get ensnared in their venom-filled tentacles. Of the 1,000 species of anemones found in shallow coastal waters (and occasionally in deeper water) across the globe, a handful has the ability to move — though they’ll never set any speed records. At best they can travel four inches an hour. Some creep along on their suction foot. Others appear to be somersaulting. Still others locomote by flexing their bodies.

Watching them in motion can be fun. Barbara recalls seeing a golden crinoid traversing the side of a nearly vertical wall one night last summer on Grand Turk. “I knew anemones could move,” she says, “but I didn’t realize they could change neighborhoods!”

Famous for symbiotic relationships, the clever anemone sometimes catches a lift from a passing hermit or decorator crab, who appreciates the camouflage covering the anemone provides (as well as protection from crafty octopi, who love to feast on crab). The anemone benefits not only with a speeder ride, but he often gets lucky and catches falling pieces of food that the sloppy crab doesn’t quite manage to polish off.

Sea anemones come in all sizes, shapes and colors, but in the waters surrounding the TCI, we tend to see the tubular-tentacled species that Barbara has so beautifully captured for this story. The tentacles serve two purposes. Not only do they protect the animal, but they are what it uses to catch food. Those undulating “fingers” that we divers and snorkelers admire from a distance are studded with microscopic stinging capsules (called nematocysts), and at the slightest touch or provocation will eject a harpoon-like filament that paralyzes its prey with a poisonous neurotoxin. (This is what gives the anemone that sticky feeling.) Favorite victims — er, meals — include fish, mussels, zooplankton, shrimp and worms. On the flip side of the food chain, sea anemones have very few predators themselves: mostly just nudibranchs, snails, sea stars and certain fish, like the Tompot Blenny.

Sometimes anemones reproduce simply by dividing in two, with each half forming a new animal (an act called lateral fission) or by “budding off” baby sea anemones. But sea anemones occasionally enjoy an exciting sex life. In addition to the fission method, they also engage in sexual reproduction and release eggs and sperm through their “mouths” that produce free-swimming larvae, which will eventually settle and grow into a single polyp. Like many other marine creatures, some anemones are distinctly male, others clearly female, and some are protandric hermaphrodites (i.e., first male, then female).

But it’s not all fun and games in the life of a sea anemone. The pharmaceutical industry and medical research teams are studying different ways the unique qualities of this creature can be put to use to help humans. One thing that’s being studied is how the neurotoxin emitted by the tentacles to catch prey might help certain cardiac problems. Last year British scientists began experimenting with blending the stinging threads into skin cream to produce a needle-free way of delivering insulin to diabetic patients. And most recently, researchers have extracted a fluorescent protein from a certain bright-red species of anemone that holds promise in imaging technologies. Two years ago, researchers who discovered a similar protein in a jellyfish that advanced biological imaging won the Nobel Prize for Chemistry. This could prove the most dramatic symbiotic relationship of all.