sponges. Rathbun (1887), Moore (1910b), Craw- 

 shay (1939), and others mention both local and 

 widespread kills due to heavy rains and sudden 

 runoff from rivers. Most of this type of destruc- 

 tion occur in relatively shallow water within a 

 few miles of shore. The salinity tolerances of 

 sponges and the detrimental effects of tempera- 

 ture were discussed in the section on ecology. 



Parasites an(j Epizoics 



With so many animals and plants living in the 

 mass of the sponge, in the internal canals, or 

 on the surface, it is difficult to establish which 

 are harmful and which are merely living in or 

 on the sponge as epizoics. No detrimental 

 animal or plant, with the exception of the 

 disease fungus, can be said to be parasitic ex- 

 clusively on commercial sponges. Many ani- 

 mals such as the small snapping shrimps are 

 found in far greater numbers in the canals of 

 the sponges than in any other habitat, but no 

 true case of commensalism can be stated. 



Commonly associated with the commercial 

 sponges and growing on the surface are such 

 algae as the fairy cup, AcetabulaHa crenulata Sind 

 Batophora oerstedi, as well as various species 

 of Halimeda and Other calcareous algae. So 

 great is the mass of plant material on the sur- 

 face of some sponges, especially those grow- 

 ing in the warmer and shallower water, that 

 the shape becomes considerably distorted. 

 These plants may not greatly affect the total 

 growth of the sponge; however, the distortion 

 reduces the commercial value. Plants that 

 cover any of the inhalant pores or restrict the 

 flow of the oscules adversely affect sponge 

 growth. 



Any animal living within any of the inhalant 

 pores, the internal canals, or the oscules would 

 be similarly detrimental to the sponge. A num- 

 ber of 1/2-inch long hydrolds live within the 

 small inhalant pores of the wool sponge and 

 stretch out from the sponge. Such hydroids 

 are commonly associated with other types of 

 sponges as well, for example, the tubular 

 sponge, Callyspongia vaginalis. The anemone, 

 Aiptasia, may form depressions in 

 the surface of the sponge into which it can 

 retract. 



Various kinds of polychaete worms, some of 

 considerable length, have been found in the 

 canals. One common worm was Leodice 

 spongicola, but there were also a number of 

 small free-swimming syllid worms and a few 

 tube-forming terebellids. In some of the non- 

 commercial sponges, polychaete worms may 

 be as long as 2 or more feet, although none of 

 this length were found in the commercial 

 sponges examined. 



Common inhabitants of the larger canals, the 

 oscules, and shallow depressions on the surface 

 of the sponge were many small brittle stars 

 such as Ophiactis savigny. The Starfish, 

 Echinaster, has been found on sponges which 

 bear small cuts or lesions in the surface, but 

 there has never been any evidence that the 

 damage to the sponge was initially caused by 

 the starfish. 



By far the commonest inhabitants of the 

 canals of the commercial wool sponge are 

 various species of the snapping shrimp. 

 Synalpheus brooksi, S. meclendoni, and S. brevi- 

 carpus were the three identified. Other shrimps, 

 such as the portunid CoralUocaris pearsei and the 

 stomatopod, Gono(/actyZus oerstefft, similar to the 

 ghost shrimp, have also been found. A number 

 of species of small crabs of the genus Mithrax 

 are also common. 



Major damage to the commercial value of the 

 wool sponges is caused by the sponge crab, 

 Pilumnus sayi, a small hairy animal that may 

 attain a width of 2 inches. This crab often 

 occupies a hole at the base of the sponge (fig. 

 17). The original hole may be the result of 

 local damage to the sponge, but constant occu- 

 pation by the crab prohibits regrowth and fill- 

 ing in of the hole. There is no evidence that the 

 crab eats any of the sponge. The hole may not 

 affect the sponge as a living animal but cer- 

 tainly destroys the commercial value of the 

 sponge almost completely. Damage by this 

 crab most frequently occurs to wool sponges 

 in the Pepperfish Key sponging grounds, just 

 north of Cedar Keys. 



Other Crustacea commonly found in the 

 canals are ostracods, such as CylindolebeHs 

 floridana; the amphipod, LeucotAoe spmicafpa,and 

 various isopods. The barnacle, Balanus decUvis, 



49 



