Compared to the seagrass and algal cover, the sessile benthic fauna of 

 the Reef Flat has only minor significance. Occurrence of sponges is negligible 

 and the number of stony corals ^ery limited. Specimens are usually small, 

 encrusting, and rather scattered, with the species Porites astreoides , Diploria 

 clivosa , Millepora squarrosa , M. complanata , and Siderastrea siderea , most 

 noticeable. A number of medium-sized coral colonies, mainly of the species 

 Montastrea annularis , Siderastrea siderea , Acropora palmata , and Diploria 

 clivosa , can be found within about a 100 m distance from the seaward terminus 

 of the Reef Flat. Within this belt, several patches, almost a zone, of 

 octocorals occur. Most noticeable is Pterogorgia citrina , the smallest of 

 all Looe Key octocoral species (about 15 cm in height), which grows only on 

 the Reef Flat but is the most abundant species here, the sea fan, Gorgonia 

 vental ina , is a close second, while sea whips are represented by several 

 species of the genera Eunicea and Plexaura and sea feathers by two species 

 of Pseudopterogorgia . Although the number of octocoral species, as well as 

 their. size, remains rather small, they nevertheless represent the only benthic 

 faunal component of some significance on the Reef Flat. 



Within and adjacent to the seagrass beds of the Reef Flat, the most 

 commonly observed invertebrates include: the queen conch ( Strombus gigas ); 

 the pen shell ( Atrina rigida ); the holothurians ( Holothuria floridana and 

 Actinopygia agassizii ); and the reef squid ( Sepioteuthis sepiodea ). 



The rock and rubble areas of the Reef Flat provide an excellent habitat 

 for small invertebrates. Numerous serpulid and sabellid worms protrude from 

 the surfaces of the eroded rocks, whereas terebellids are commonly found 

 beneath them. Abundant populations of other cryptic organisms, such as 

 brittle stars and small crustaceans abound in this area. Among crabs, the 

 majids ( Mithras spp. and Stenorhynchus seticornis ), the grapsid ( Percnon 

 gibbesi ) , the xanthids ( Leptodius floridanus and Glyptoxanthus erosus ), and 

 the portunid ( Portunus spinimanus ) were most frequently observed. Small 

 gastropod and pelecypod molluscs are to be found in this area in considerable 

 abundance. Echinoderms are prolific, especial ly ophiuroids. A large population 

 of Diadema antillarum reside in this area. Other echinoids and holothurians 

 were observed but are not common. 



c. Fore Reef 



The Fore Reef zone of Looe Key is a well developed and especially spec- 

 tacular formation. Its main portion is a high profile spur and groove system, 

 bordering the Reef Flat in very shallow water and sloping down to a sand 

 bottom in 9-11 m of depth. The whole system, from easternmost to westernmost 

 spur, is about 1500 m long and, at the main center portion, about 350 m 

 wide. There are two associations, or subzones, that comprise the Fore Reef 

 complex. 



The shallowest part of the spurs, just below the surface at low tide, 

 could be called the "reef crest". However, at Looe Key it is so narrow a 

 zone (less than 20 m) that it is treated here simply as the leeward end of 

 the spur and groove system. The benthic community of this subzone consists 

 of a massive growth of firecorals, mainly Millepora complanata , but lacks 



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