Species Description: The blue Caribbean sponge, H. caerulea, is a massive to thickly encrusting species. Many of the oscules are found at the apex of cylindrical to volcano-shaped projections, which may be several centimeters tall (Hechtel 1965). Each oscule may be up to 5 mm in diameter. The projections have axial cloacae and thick walls. Living specimens are usually light blue throughout, although color may vary from yellowish green to light purplish brown (Hechtel 1965, de Weerdt 2000). Preserved specimens are dull beige in color. Consistency is also variable, from soft and easily broken to stiff and somewhat compressible (Hechtel 1965). The surface is variably smooth to rough. Some areas, especially near the base, have a detachable dermal layer. In some areas, filamentous algae grow through the tissues, and algal debris litters the interior. Oxeas are slightly curved, fusiform to wedge-shaped, and generally 3-9 x 117-200 μm. Sigmas are thin, often sharply curved in the middle, and around 12-30 μm long.
Habitat & Regional Occurrence: H. caerulea occurs in Florida, along the coast of the Gulf of Mexico, throughout the Caribbean, in Jamaica, and on the Pacific coasts of Mexico and Panama (Wulff 1996, World Porifera Database 2012). This species is a common fouling sponge on dock pilings, mangrove roots, wrecks, reef flats, and it can be found attached to stones and shell rubble on sand flats (Hechtel 1965, de Weerdt 2000).
Non-Indigenous Distribution: H. caerulea has been recorded outside of its native range on the reefs surrounding Palmyra Atoll in the central Pacific Ocean (Knapp et al. 2011).
Size: Individual H. caerulea are approximately 8 cm in height (de Weerdt 2000).
Predators: Documented predators of the blue Caribbean sponge include: the Cortez angelfish, Pomacanthus zonipectus; the Passer angelfish, Holacanthus passer; and the nudibranchs Hyselodoris agassizii, Glossodoris sedna, G. dalli, Discodoris ketos and Tylodina fungina (Padilla Verdín et al. 2010). D. ketos is often found inhabiting areas around the base of H. caerulea, where it adopts the color of its food source and becomes camouflaged.
Associated Species: H. caerulea has a well-documented mutualistic relationship with the red calcareous alga, Jania adherens (Carballo & Ávila 2004, Ávila 2007, Cruz-Barraza & Carballo 2008). This relationship is especially evident on rocky substrates in high-energy subtidal areas where H. caerulea often grows between the branches of J. adherens (Ávila 2007). It is believed that the sponge gains protection from predators and increased structural support from the alga, while the alga can increase its height due to the growth of the sponge around its branches.
As with other sponge species, H. caerulea provides a home for several organisms, including the snapping shrimps Synalpheus wickstenae and S. stylopleuron (Salazar & Hendrickx 2006).
Ávila E, Carballo JL & JA Cruz-Barraza. 2007. Symbiotic relationships between sponges and other organisms from the Sea of Cortes (Mexican Pacific coast): same problems, same solutions. Porifera Research: Biodiversity, Innovation and Sustainability: 147–156.
Carballo JL & E Ávila. 2004. Population dynamics of a mutualistic interaction between the sponge Haliclona caerulea and the red alga Jania adherens. Mar. Ecol. Prog. Ser. 279: 93-104.
Cruz-Barraza JA & JL Carballo. 2008. Taxonomy of sponges (Porifera) associated with corals from the Mexican Pacific Ocean. Zoo. Stud. 47: 741-758.
De Weerdt WH. 2000. A monograph of the shallow-water Chalinidae (Porifera, Haplosclerida) of the Caribbean. Beaufortia 50: 1-67.
Hechtel GJ. 1965. A systematic study of the Demospongiae of Port Royal, Jamaica. Bull. Peabody Mus. Nat. Hist. 20: 1-103.
Knapp IS, Godwin LS, Smith JE, Williams CJ & JJ Bell. 2011. Records of non-indigenous marine species at Palmyra Atoll in the US Line Islands. Mar. Biodiv. Rec. 4.
Padilla Verdín CJ, Carballo JL & ML Camacho. A qualitative assessment of sponge-feeding organisms from the Mexican Pacific Coast. Open Mar. Biol. J. 4: 39-46.
Salazar MH & ME Hendrickx. 2006. Two new species of Synalpheus Bate, 1888 (Decapoda, Caridea, Alpheidae) from the SE Gulf of California, Mexico. Crustaceana 78: 1099-1116.
World Porifera Database. World Register of Marine Species. Online: http://www.marinespecies.org/porifera. Accessed 25 November 2012.
Wulff JL. 1996. Do the same sponge species live on both the Caribbean and eastern Pacific sides of the Isthmus of Panama? Bull. Inst. Roy. Sci. Nat. Belg. 66: 165-173.