The Flora and Fauna of a Basin in Central Florida Bay 



By 



J. HAROLD HUDSON, DONALD M. ALLEN, 



and 



T. J. COSTELLO, Fishery Biologists 



Bureau of Commercial Fisheries 



Tropical Atlantic Biological Laboratory 



Miami, Florida 33149 



ABSTRACT 



One hundred ninety-six species of plants and animals are reported fronn a nur- 

 sery area for pink shrimp, Penaeus duorarum duorarum , in a basin of central Flor- 

 ida Bay. Many of the organisms are benthic and associated with shallow beds of 

 turtle grass, Thalassia testudinum . Although abrupt habitat variations may affect 

 species distribution, the general distribution of organisms in the basin and bay de- 

 fines environments influenced by different water masses. 



INTRODUCTION 



Florida Bay is at the southern tip of the 

 Florida peninsula. The bay serves as a nur- 

 sery ground for pink shrimp, Penaeus duora- 

 rum duorarum , before they move to the Tor- 

 tugas shrimping grounds, northwest of Key 

 West (Costello and Allen, 1966). 



As part of an ecological study of the Tor- 

 tugas pink shrimp population, we made a 

 sampling survey of young pink shrimp and 

 associated organisms in central Florida Bay 

 (fig. 1). The incidence of certain plants and 

 aninnals in the bay may help us detect en- 

 vironments that are suitable for young pink 



shrinnp. With few exceptions, the plants and 

 animals collected were identified to species 

 and form the list contained in this prelimi- 

 nary report. Except in very general terms, 

 we make no attempt to relate these organisms 

 to the environment. Distribution, abundance, 

 and ecology are left for a later report. 



Past ecological studies in Florida Bay in- 

 clude those by Tabb and Manning (1961) and 

 Tabb, Dubrow, and Manning (1962). Their work 

 was confined to the northwestern section of 

 the bay, whereas our report concerns central 

 Florida Bay. 



DESCRIPTION OF AREA 



Detailed descriptions of the Florida Bay 

 environment were given by Ginsburg (1956) 

 and Gorsline (1963). This shallow bay has an 

 extensive complex of mangrove keys and in- 

 tersecting mudbanks covered with seagrasses. 

 The network of banks and keys separates the 

 bay into semienclosed basins, locally called 

 "lakes," 40 to 300 cm. deep. 



Porpoise Lake, which we selected for study, 

 is a triangular- shaped basin in the east- 

 central portion of the bay (fig. 1), It is bor- 

 dered on the northwest by the Foxtrot Keys 

 and on the north by Bob Allen Key (fig. 2). The 

 lake has an area of about 10.4km.^ and a maxi- 

 mum depth of 210 cm. Sediments in the lake 



and on surrounding banks are mainly carbo- 

 nate mud mixed with varying amounts of shell 

 fragments and plant detritus. The banks are 

 carpeted with extensive beds of turtle grass, 

 Thalassia testudinum , which extend into the 

 lake but thin rapidly with increasing water 

 depth. The fringe area between the Thalassia 

 and the keys is narrow and covered inter- 

 mittently with sparse patches of shoal grass, 

 Diplanthera wrightii . 



Numerous small channels cut through the 

 enclosing banks to connect Porpoise Lake with 

 surrounding lakes and, finally, the Atlantic 

 Ocean and Gulf of Mexico. The depth of these 

 channels varies from 80 to 245 cm., and they 



