Cliona delitrix Pang 1973

Excavating sponge that lives on coral mounds, eats non-living basal portions of the coral while killing adjacent surface coral polyps. Orange in color and found encrusting coral structures. Exhibits large, lighter-colored osculas and occasionally pebbly areas.

'A marked increase in the biomass of Cliona delitrix infesting Montastrea cavernosa substrate occurred in a portion of the Grand Cayman fringing reef affected by the discharge of untreated fecal sewage. It is suggested that the six-fold increase in bacteria biomass (both "coliforms" and natural marine bacterioplankton) in reef waters receiving the sewage effluent is linked to a five-fold increase in sponge biomass at the polluted site relative to a control site. The elevated density of C. delitrixbiomass signifies a similar increase in the amount of M. cavernosa skeleton that has been eroded by this sponge and reduced to silt-sized sediment. Thus, the proliferation of a bioeroding organism in the sewage-stressed environment has caused a shift in the carbonate balance on the reef.' (Rose, Risk, 2008)

Florida Keys, Bahamas, Caribbean.

3-50 inches in diameter