The red-beard sponge resembles seaweed with its thick, finger-like branches.
The red-beard sponge resembles seaweed with its thick, finger-like branches.
Courtesy: University of Charleston, S.C.

Red-beard Sponge (Microciona prolifera)

Alternate common names: Red Sponge.
Color: Distinctively bright red or orange.
Size: Up to 12 inches wide and 8 inches high.
Habitat: Attached to rocks, pilings, or other hard objects in shallow bays; salt marshes or estuaries.
Seasonal appearance: All year.


Red-beard sponges are a species of sponge found in Rhode Island that exists in two different forms. They begin as thin encrusting layers and eventually develop into heavy masses. Although species of sponges are difficult to tell apart, red-beard sponges are the only sponges in Rhode Island with thick, fleshy, intertwined fingerlike branches.

Life History and Behavior

Sponges are colonies made up of many individuals living within a hard shell-like capsule. They are animals, not plants, and can be found in many different habitats and forms. Considered primitive animals, sponges lack true tissues and organs. A firm exoskeleton that consists of pores used for feeding and respiration surrounds the fleshy material of the body. Water is brought through cilia-lined pores into the hollow cavity of the sponge. As water passes through the pores, the cilia trap oxygen to breathe and phytoplankton for food. Once the nutrients are removed, the water and waste products exit the sponge through an opening at the top.

Sponges are filter feeders and cannot live out of water. They need a constant flow of water and are most common in areas where they are constantly covered by water. Eggs develop within the sponge itself and are released as free-swimming larvae. Once they have undergone a planktonic stage, sponges will attach to a substrate and become stationary.

Special Notes

Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.