3. Reef Biota . 



a. Hallandale Beach . The low profile first reef off 

 Hallandale Beach was marked most conspicuously by scattered tufts 

 of filamentous red algae, primarily Graailaria sp. and, to a lesser 

 extent, Covynomorpha clccoata (Fig. 7). The coralline red alga, 

 Amphiroa fragilissima, and the bro\m alga, Dictyota sp. , were also 

 common along with the green algae, Udotea congluti-nata, Ealimeda 

 opuntia^ and Ulva lactuca. 



Marine invertebrates on the first reef were notably scarce, 

 represented primarily by octocorallians (mostly Pseudopterogorgia 

 aaerosa and Eimiaea spp.). Stony corals were very small and 

 sparsely distributed, and sponges, mostly the heavenly sponge 

 (Dysidea etherea) , were noted only occasionally. The scarcity of 

 marine animals on the first reef was probably due in part to the 

 generally turbid conditions. Most species of reef fauna, particu- 

 larly corals, are highly susceptible to siltation and are generally 

 restricted to clear, sediment-free waters. Also, most of the 

 limestone surface of the first reef was covered by a thin layer of 

 sand which probably discouraged the settling and attachment of 

 sessile fauna. 



Underwater visibility was generally good on the second reef 

 due to the greater depth and decreased wave surge. Algae along the 

 inner edge of the reef were represented by the same species present 

 on the first reef, with Udotea congtutinata the most abundant. 

 The inshore edge of the second reef was populated by a greater 

 number and variety of octocorallian and madreporarian corals than 

 the first reef, although these corals were still fairly sparsely 

 distributed. Both groups became more abundant toward the interior 

 and outer edge of the reef. Several species of Euri'icea and Pseu- 

 dopterogorgia were fairly common inshore, as well as the large star 

 coral (Montastrea cavernosa) , the clubbed- finger coral (Porites 

 porites) , and the star coral {Favia fragim) . Sponges were repre- 

 sented primarily by the red sponge (Haliclona rubens) and the 

 boring sponge {Cliona lampa) . Several specimens of the long-spined 

 urchin {Diadema antillarim) were also noted. 



Toward the center of the second reef (Fig. 8) the density 

 and diversity of fauna greatly increased, although the algae were 

 somewhat less abundant than at shallower depths. In particular, 

 Udotea conglutinata, which had been dominant near the inshore edge 

 of the reef, was virtually absent; Graoilaria sp. was the only 

 common algal species. Soft corals were especially, abundant and 

 represented by many species, including Plexaura flexuosa, Muriaea 

 atlant-ica, and several species of Eunioea. Stony corals were 

 primarily rose coral {Manioina areolata) , staghom coral {Aoropora 

 cerviaomis) , and the large star coral [Montastrea cavernosa) . 

 Hydrocorals {Millepora alcicomis) and a variety of sponges were 

 also common. Motile crustaceans, including arrow crabs {Stenorhyn- 

 ahus seticomis) , banded coral shrimp (Stenopus hispidus) , and 

 spiney lobsters [Panulirus argus) , were often observed among sponges 

 and corals or in crevices within the pitted limestone surface. 



