Marine Wildlife Encyclopedia
Yellow Tube Sponge Aplysina fistularis
Species ID Code: P.AF
Description: Several rough and thickly-walled tubes, connected at their base. These tubes are always in a vertical or near-vertical orientation and appear bright yellow in shallower water, although it may be darker yellow to orange in deeper water
Maximum Size: 1 m (3 ft)
Longevity: Unknown, may be over 100 years based on the longevity of related species
Status: Not currently on the IUCN endangered species list
Yellow Tube Sponge & People: These sponges are not harvested for human use aside from occasional collections for sale as soft bathing sponges, since this species does not contain prickly structural elements known as spicules. Recent scientific studies have shown that these sponges produce chemicals with antimicrobial as well as antifouling properties. This discovery could make this sponge useful to humans in the near future if these properties can be harnessed and used to prevent the attachment of fouling marine organisms to hard surfaces like boat hulls, rather than the toxic chemicals currently in use for this purpose
Geographical Range: This species is common throughout the Caribbean, Florida and the Gulf of Mexico
Coral Reef Zone: Common in the fore reef and drop-off zones
Favourite Habitats: Often found in areas exposed to medium or strong currents which provide the sponge with a constant supply of food particles to filter from the water
Depth Range: 4–30 m (13–100ft)
A Day in the Life
Sponges have no known daily schedule. Most activities such as filter-feeding, recovery growth, and budding are thought to occur continuously. Spawning, however, is thought to occur near dawn in this species
Scuba Diver & Snorkeler Best Practices
Don’t wear gloves on the coral reef. Gloves are for skiing! You’re not likely to get cold in water above 25o C (77o F). Wearing gloves only encourages you to touch the reef, so please leave the gloves at home.
Who Eats Who?
Yellow tube sponges are filter-feeders, consuming plankton, detritus (dead organic matter) and bacteria that drift in the oceans currents. These sponges are consumed by a number of different coral reef organisms, such as angelfishes, filefishes, cowfishes and spadefish, as well as the hawksbill sea turtle.
Sponges are simple organisms. They lack many of the basic senses used to detect the sound and smell of approaching predators. Even if a sponge could detect the approach of a potential threat, there is little they could do about it, since they are sessile organisms and therefore unable to move.
Sponges are filter feeders, meaning they pump water through their structure and filter out plankton, detritus, and even bacteria to consume. An inward current of water is created by beating tiny whip-like hairs on specialized cells, called collar cells, hidden within the internal structure of the sponge. As the water is sucked in, the collar cells also capture food particles in the water, digest them, and transport the nutrients to other cells in the sponge. Water is taken in by the sponge along the entire length of the tubes, and exits only through the large opening at the top. Filter feeding in tropical sponges is constant, regardless of the season or time of day.
Observe, record & share:
OP.AF-101 – Filter-feeding: Observe the way visible particles floating in the water are deflected by the current produced by the sponge, and if you place your hand above the opening at the top of large specimens (without touching them) you may feel a very slight current of exhaust water.
Attack & Defense Behaviour
Sponges cannot move around and so most of their defensive mechanisms are undetectable by divers. However, under certain circumstances, aspects of this behaviour can be observed directly. This species, and other sponges, produce chemicals that make them unpleasant to eat, or that make them difficult for other sea creatures, like algae and barnacles, to attach to. While this component of their behaviour is not always apparent to divers and snorkelers, the sponge’s ability to rapidly reorganize its structure sometimes can be. When sponge tubes are knocked over by strong waves, they can move their existing cells around and form new, upright tubes in a matter of weeks without having to grow new tissue.
Observe, record & share:
OP.AF-201 – Upright recovery: Old sponges that have been knocked down may have new, vertical branches growing out of their side
Very little is currently known about the reproductive behaviour of the yellow tube sponge. Most sponges studied to date are hermaphrodites, capable of producing both both eggs and sperm, although some species have separate males and females. During the reproductive season, usually in the warmer summer months, eggs and sperm are released from sponges over a period of several days. The eggs become fertilized and begin to develop as they drift, and eventually settle on a hard surface to begin growing into a new individual. Sponges can also reproduce sexually, by division and fragmentation, in the same way as many plants. Small buds form at the top of the tube year round and, eventually, these buds break off and float away to settle in another area. Similarly, pieces of the sponge that are broken off during storms and other disturbances can re-attach to the bottom and grow into a new sponge.
Observe, record & share:
OP.AF-301 – Division: Yellow tube sponges may have small buds at the top of the tube, these often look like they are “dripping” upwards from the sponge
OP.AF-302 – Fragmentation: Broken pieces of sponge, which land on the seafloor, can attach and re-grow
OP.AF-303 – Spawning: Sponges emit a cloud of eggs or sperm from their tube, often resembling small bubbles or smoke, respectively
Filter-feeding: Sponges are filter-feeders, and as water is sucked into the sponge, collar cells lining the sponge’s pores capture suspended food particles. Water is taken in by the sponge through pores all along the length of the tube, but water exits only through the large opening at the top of each tube. Sponges are very efficient at this process, and are able to pump the equivalent of five times their own volume in water per minute.
Did You Know?
• When this sponge is exposed to the air its colour changes from yellow to purple, and eventually to black, as a result of biological reactions in the tissues associated with death. Sometimes, snorkelers or divers may see yellow tube sponges underwater that are beginning to turn purple, which may indicate that this individual sponge is in poor health and perhaps succumbing to disease.
• The yellow tube sponge and other sponge species have a symbiotic relationship with photosynthetic bacteria. Sponges however, are not as dependant on this relationship as corals are on their relationship with their symbiotic algae. As a result sponges can thrive in much deeper and darker waters than most corals can.
• Sponges are some of the most ancient and basic animals on the planet, and have changed very little since their appearance 600 million years ago. They are ubiquitous in the world’s oceans and flourish even in the frigid waters of the Arctic and Antarctic, where some incredibly slow growing specimens are estimated to be over 15,000 years old!
What to do?
Share your observations today!: Discover your species of interest, observe its behaviour, and share your pictures and videos with friends and coral reef enthusiasts around the world! Upload media to the web, tagged with species common name (ex.: trumpetfish) and species ID code (ex.: A.AM) or species behaviour code (ex.: A.AM-101)