Species Description: The bumpy ball sponge, Ircinia strobilina is massive, often with stubby cylinders wider than high (Wiedenmayer 1977). Specimens growing in strong currents usually become elongate in a direction perpendicular to the current, with a longitudinal apical crest bearing the oscules. Most specimens are cake or pillow shaped, as the two common names indicate. Live individuals are grey to black externally, with drab yellow at the base and in the choanosome. Their consistency is tough and spongy. The surface is coarsely conulose. Thick, blunt conules 3-8 mm high and 3-8 mm apart are often tipped in white and connected by ridges, especially near the base where they are lower and farther apart (Wiedenmayer 1977, Gammill 1997). The oscules are 2-5 mm in diameter, scattered in groups on the top plane, and often very crowded.
Potentially Misidentified Species: The bumpy ball sponge resembles the starry stinker sponge, I. felix. Both species have similar ectosomes and choanosomes (Wiedenmayer 1977). However, the fibers and the meshwork in the choanosome of I. felix are coarser, and connective fibers are rare.
Habitat & Regional Occurrence: I. strobilina occurs from 10 to 100 feet, mostly in inner-reef areas and in lagoons among beds of the turtle grass, Thalassia testudinum (Kaplan 1988). The geographic range of the bumpy ball sponge extends from Florida to the Bahamas and throughout the Caribbean to Brazil (Kaplan 1988, Gammill 1997). In the Bahamas, this species is found on rocky substrate, where it grows successfully on the bottoms of rocky reef channels in strong currents (Wiedenmayer 1977).
Size & Growth: The diameter of I. strobilina ranges from 5 cm to over 1 m (Wiedenmayer 1977). Individuals tend to grow faster vertically than horizontally, with most growth occurring when the specimens are small (Hoppe 1988). Assuming constant growth rates, I. strobilina can show an annual increase in volume of approximately 11%.
Abundance: The abundance of I. strobilina in the IRL is undocumented, but densities of up to 19.3 individuals per 100 m2 have been documented for populations in the Bahamas (Wiedenmayer 1977).
Reproduction & Embryology: Reproduction of the bumpy ball sponge in the IRL is undocumented. However, I. strobilina exhibits reproductive activity year round on the reefs of Curaçao (Hoppe 1988b). Spermatic cysts are produced to varying degrees throughout the year, while oocytes and larvae have been observed from September to April, for an annual breeding season of 8 months. The sponge is viviparous with separate sexes, although the possibility of protandry cannot be ruled out.
Predators: The bumpy ball sponge has been found in the stomach of the queen angelfish, Holocanthus ciliaris (Randall & Hartman 1968), and it is likely consumed in at least small quantities by other predators as well. However, other studies have found that fishes that were force-fed I. strobilina exhibited paralysis and narcosis (Hoppe 1988a). I. strobilina and related species produce linear furanosesterterpene tetronic acids, which give the sponges a characteristic garlic odor, and may warn potential predators that the species is unpalatable and potentially toxic (Pawlik et al. 2002).
Associated Species: Like many other sponges, a variety of organisms can be found living in association with the bumpy ball sponge. The coral, Porites astreoides, and the sponge, Haliclona viridis, have been found along with I. strobilina (Wiedenmayer 1977). In Brazil, the tusked goby, Risor ruber, often lives beside or within the sponge (Rocha et al. 2000).
Individuals are frequently overgrown by other species of encrusting, branching, tubular, and turbinate sponges in reef areas where vacant space is in short supply (Engel & Pawlik 2005).
Economic Importance: Like many other species of marine sponges, I. strobilina produces chemical metabolites that are isolated, identified and studied for potential antifouling and/or pharmaceutical uses (e.g. Epifanio et al. 1999).
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