their use of the bay by the availa- 

 bility of protective habitat, depth, 

 turbidity, or salinity and tempera- 

 ture extremes. 



Seagrass detritus from Florida 

 Bay is exported either across the 

 coral reef tract or to the gulf 

 continental shelf. The exchange of 

 sediments and detritus between the 

 Keys and Florida Bay is discussed 

 below with the Florida Keys eco- 

 system. 



8.32 INVERTEBRATES 



Only a few groups of inverte- 

 brates have been extensively studied 

 in Florida Bay, namely the mollusks 

 (Turney and Perkins 1972), the fora- 

 minifera (Moore 1957, Rose and Lidz 

 1977), and the insects (Simberloff 

 and Wilson 1969, Simberloff 1976). 

 Tabb and Manning (1961) and Tabb et 

 al. (1962) present data on selected 

 invertebrates near Flamingo, and 

 Hudson et al. (1970) present a list 

 of species collected from a lake 

 setting near central Florida Bay. 

 In all, Turney and Perkins (1972) 

 identify 140 molluskan species from 

 100 genera in Florida Bay. Species 

 characteristic of the four major 

 subenvironments appear in Table 36. 

 In addition to these rather charac- 

 teristic faunal assemblages, a vast 

 portion of the west central bay 

 exhibits a transitional fauna inter- 

 mediate in composition between major 

 subenvironments. 



Some localized faunal variation 

 was noted between lake and mud bank 

 environments in the interior suben- 

 vironment, but not in the Gulf or 

 Atlantic. Throughout the bay, cer- 

 tain shallow water and intertidal 

 mollusks were not generally found on 

 mud banks awash at low tides unless 

 the banks were close to dry land. 

 Hudson et al. (1970), working in 

 central Florida Bay, report that 



several invertebrates exhibited a 

 discontinuous distribution over the 

 superficially homogeneous substrate 

 of a single lake basin. 



Curiously, nearly 40% of the 

 molluskan species reported by Tabb 

 et al. (1962) in northwestern Flor- 

 ida Bay were not reported by Turney 

 and Perkins (1972). It is suspected 

 that taxonomic inconsistency is the 

 reason for this puzzling fact, but 

 this is not the only possibility. 

 Tabb et al. (1962) report only about 

 15% overlap in species from the 

 Florida Bay study area and nearby 

 Biscayne Bay. 



Consistent with the hypothesis 

 of a broadly gradational fauna in 

 Florida Bay, Hudson et al. (1970), 

 report three invertebrate species, 

 the nobby star coral (S olenastrea 

 hyades ) , the long spined sea urchin 

 ( Diadema antillarum ), and the spiny 

 lobster ( Panulirus arqus ), inhabit- 

 ing the channels between the lakes 

 rather than the seagrasses. These 

 species, along with fishes such as 

 the school master ( Lutjanus apodus ) 

 and the sargent majors ( Abudefduf 

 saxatilis ) , are generally found in 

 Atlantic waters but not along the 

 gulf coast. 



Of primary importance to com- 

 mercial interests is the role of 

 seagrasses in Florida Bay to shrimp- 

 ing in south Florida waters. A 

 significant research effort over a 

 number of years has shown that Flor- 

 ida Bay and Whitewater Bay serve as 

 nursery grounds for pink shrimp 

 ( Penaeus duorarum ) before they move 

 to the Tortugas shrimping grounds 

 northwest of Key West. This infor- 

 mation is summarized in Section 

 9.32. 



Foraminifera in Florida Bay are 

 characteristic of a circulation 

 restricted, carbonate bay that is 



169 



