Giant Barrel Sponge (Plate 16)

Giant Barrel Sponge - Xestospongia muta, Phylum Porifera, Class: Sponges Demospongiae³

These spectacular sponges can live to be over 2000 years old! The ones in this photograph are more likely to be less than 100 years (based on the fact that they grow an average of 1/2 an inch a year).

Sponges are filter feeders. Small holes (incurrent pores) draw water into the sponge. It's not the type of eating that you can witness, but you can find evidence of it during a night dive. By waving your hand near the outside of one of these sponges at night (being very careful NOT to touch it) the sponge will appear to glow. What you are actually seeing is the bioluminescence of the water drawn into the sponge.

"Visual ID: Huge barrel-shape with rough, often jagged, stone-hard exterior. Shades of gray, brown, or red-brown. Generally solitary, but one or two smaller individuals occasionally grown around base."

Click here for more pictures of sponges.

³Humann, Paul. Reef Creature Identification, Florida Caribbean Bahamas. Ed. Ned DeLoach. Jacksonville, FL: New World Publications, Inc., 1996.

Photograph by Valerie Hayken. 2004 copyright Valerie Hayken

All sizes are in inches. Which framing option is right for you?