With the exception of a few plankton- particulate feeding pelagic 

 species which apparently are platform residents, the pelagic predators 

 (e.g. king mackerel, blue runner) and their prey (e.g. scaled 

 sardine), essentially "drift" through the system as do suspended 

 plankton and particulates, but the former are characterized by slightly 

 longer residence times. The attraction of large predatory gamefish to 

 structures is well-known, resulting in increased predation from the top 

 predator — man. The benthic reef fish community (usually dominated by 

 red snapper), is also subjected to increased predation by man. Red 

 snapper aggregate at platforms, apparently only for purposes of cover 

 since most of their diet is composed of organisms from the soft-bottom 

 demersal fish and macrocrustacean community. 



The trophic dynamics of the natural banks of the outer shelf reefs 

 have not been adequately investigated. Corals are dependent upon 

 plankton for food, but are greatly benefited by their symbiotic 

 zooxanthellae, unicellular algae. The algal photosynthesis and 

 concomitant respiration by the coral are mutually beneficial. In 

 addition to the hermatypic corals, coralline algae also contribute to 

 reef formation. Other primary producers of the coral reef community 

 include leafy algae. Corals are preyed upon by numerous species; the 

 most noticeable include parrotfishes and sea urchins. Reefs provide 

 habitat for a large array of animals ranging from small plankton- feeding 

 reef fishes to large snappers, groupers, and grunts. Many of the latter 

 are believed to obtain most of their food from the surrounding 

 soft-bottom communities. Coral reef habitats are unusually diverse and 

 ornate. Their physical structure results in complex biological 

 interactions having no rivals among other shelf systems. 



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