(1972) offer the best alternative, 

 an empirical zonation based on a 

 quantitative analysis of molluskan 

 faunal composition. Delineation of 

 these zones was presented earlier in 

 Chapter 5.6. Salinity, temperature, 

 and other environmental conditions 

 of these four subenvironments are 

 summarized in Table 36 along with 

 the molluskan composition. A map of 

 these zones was presented earlier in 

 Figure 38. 



8.3 HABITAT PARTITIONING 

 FOR FISH AND WILDLIFE 

 PRODUCTION 



8.31 ENERGY FLOW 



The environment in Florida Bay 

 is a unique combination of saline to 

 hypersaline physical/chemical condi- 

 tions harboring a luxuriant growth 

 of sea grasses and calcareous algae. 

 Although some work has been conduc- 

 ted on the productivity of algae, it 

 was not done from an ecological 

 point of view but rather as an esti- 

 mate of contributions of calcareous 

 algae to the lime mud sediments of 

 the bay (Stockman et al. 1967). 



Recently Zieman (1982) suggest- 

 ed three major pathways by which 

 seagrasses influence fish and wild- 

 life productivity: 



(1) internal productivity of 

 resident species biomass; 



(2) productivity by virtue of 

 their association with near- 

 by communities such as coral 

 reefs, mangroves, and the 

 continental shelf; and 



(3) through the export of sea- 

 grass detritus. 



Incorporating these basic con- 

 siderations within the context of 

 the Florida Bay environment. Figure 

 55 is presented as a general model 

 of fish and wildlife production in 

 the bay. Internal productivity of 



resident biomass is limited to the 

 primary producing substrates, large- 

 ly dominated by seagrasses, and the 

 resident primary and secondary 

 consumers as indicated. These are 

 divided into the intertidal and 

 above group (insects of the mangrove 

 islands, fiddler crabs and the like) 

 and below the intertidal group, 

 including herbivores (shellfish, sea 

 turtles, polychaetes, and herbivo- 

 rous fish such as mullet) and middle 

 consumers (pinfish, conchs, and 

 croakers) . 



Composition of the top predator 

 component (and to some degree the 

 other components) is shown as being 

 gradational depending on proximity 

 to the respective associated commu- 

 nities. In the northern bay it is 

 likely that faunal composition is at 

 least periodically influenced by 

 species characteristic of the main- 

 land mangroves. Although not as 

 well flushed as upper parts of 

 Whitewater Bay, northern Florida Bay 

 is subject to a similar cycle of 

 rainfall and runoff. The quantities 

 of runoff, nutrient loadings, and 

 salinity and temperature extremes 

 are no doubt different in Florida 

 Bay than along the southwest coast; 

 however, the effects of these and 

 other influencing factors on the 

 productivity and faunal composition 

 of upper Florida Bay remains largely 

 unknown. 



Where the bay interfaces with 

 the moderating influences of the 

 Gulf of Mexico and the Atlantic, it 

 is likely that faunal composition of 

 transient consumers reflects the 

 respective environments. Toward the 

 south, reef dwellers are likely to 

 wander into the lagoonal environment 

 for feeding purposes and may even 

 find protection in the crevices of 

 some limestone outcroppings. In 



general, many of the more strictly 

 marine forms are probably limited in 



166 



