The brown spiny sea star (Echinaster spinulosus) is active during the day, found among oyster beds, seagrasses, and muddy bottom habitats along Florida's Gulf coast. It has five arms, each with hundreds of tube feet, that are used for movement and feeding. Powered by a water vascular system, the sea star's tube feet use suction to pull apart the shells of its food; clams and other bivalves.
An ancient species, the horseshoe crab (Limulus polyphemus) is often referred to as a "living fossil." The horseshoe crab as we know it today has inhabited our oceans for almost 350 million years. It is classified with crabs (phylum Arthropoda), but it is not actually a crab or even a crustacean. It is a benthic (bottom-dwelling) predator that uses its small pinchers to pick through the sand for clams, worms and other critters that make up its diet. Each spring, mature horseshoe crabs spawn in shallow coastal areas where their eggs serve as a critical food source for migrating shorebirds. The Atlantic horseshoe crab, one of only four horseshoe crab species worldwide, is found in coastal areas from Maine to the Yucatan peninsula.
Moon jellies (Aurelia aurita) possess a short fringe of nematocysts (stinging cells) along the lower edge of their body. The sting of this jelly is relatively mild. The moon jelly moves up and down in the water column by pulsing its body, but it isn’t a strong enough swimmer to move against the current. Moon jellies often wash up on the beach after storms. The pinkish cloverleaf shaped organ visible at the center of the jelly’s bell make up its reproductive organs. Moon jellies range from Maine through the Caribbean, and can be seasonally abundant in Rookery Bay.
Width: up to 8"
Although commonly referred to as a "starfish", this animal is not a fish because it has no backbone. It is related to sea urchins and sand dollars, all members of the echinoderm (spiny skin) family. The nine-armed sea star has rows of small white tube feet under each arm that help it move and feed on organic matter in the sand. Often found buried in the sand, this sea star is able to regrow legs if wounded. We occasionally have this species in residence in the ELC Touch Tank.
This small, chocolate-colored individual looks more like a plant or strangely-colored pickle than an animal. Using its 5 rows of pinkish tube feet, the pygmy sea cucumber (Pentacta pygmaea) slowly moves across the bottom or along structure. They digest detritus (decaying organic material) from the sand. Periodically its crown of feathery white tentacles will emerge from its anterior end.
The Sand Dollar is also known as the Keyhole Urchin. It is related to urchins and starfish. They have simple, flat, round bodies with a few long, narrow holes in its body. The Sand Dollar has no head, arms, legs or feet, but it has a mouth on the bottom of its body that it uses to eat small plants and food that it finds buried in the sand. They live under the sand most of the time. When you find a white one on the beach, it’s been bleached white by the sun. They’re safe to pick up and keep.
During your next walk on the beach, you might keep these words in mind: If it’s brown, leave it down. If it’s white, it’s all right.
This anemone (Calliactis tricolor) is often found on the shells of hermit or other crabs. Anemones are sedentary, meaning they must anchor themselves to a shell or rock. They have short tentacles with stinging cells for trapping prey. Crabs sometimes relocate anemones to their shells for protection or camouflage. This is beneficial to the anemone because it gets to eat the crab's scraps.
As its name suggests, the upside-down jelly (Cassiopeia xamachana) is often found upside-down. It swims right-side up, but settles, inverted, in calm, shallow waters so it can feed. A mutually beneficial relationship exists between this animal and a type of algae called zooxanthellae, which live in the jelly's lacy oral arms. The algae produce food and energy for the jelly through photosynthesis.