Distribution of a nematocyst-bearing sponge in relation to potential coral donors

摘要: Haliclona sp. 628 (Demospongiae, Haplosclerida, Chalinidae), a sponge found on the reef slope below 5 in depth Great Barrier Reef, has two unusual characteristics. It contains symbiotic dinoflagellate, Symbiodinium sp., similar structure to dinoflagellate within Acropora nobilis (S. microadriaticum), and it coral nematocysts randomly distributed between ectosome endosome usually undischarged intact tissue. Given occurrence of 628, focus this study was determine distribution species at Heron Island Reef relation potential donors. A combination line belt transects used estimate abundance Halielona co-occurring congener, 1031, which does not contain nematocysts, three widely separated sites Reef. The different types substratum (sand, sand-covered rubble, dead A. nobilis, live other coral, coral) along each colony attached were also recorded. Despite predominance rubble all sites, 30 55% colonies comprised less than 8% available any transect. In contrast, 1031 significantly more frequently corals would be expected based availability substrata sites. Potential explanations account for donors are discussed.