APALACHICOLA BAY SYSTEM 



The Apalachicola Bay system is 

 one of the most productive estuaries 

 in Florida and contributes substan- 

 tially to the economy of Franklin 

 County. It supports a recreational 

 fishing industry and a commercial 

 fishery for oysters, shrimp, blue 

 crabs, and several fish species. 

 The oyster industry alone is re- 

 sponsible for 50 percent of county 

 income (Boynton et al. 1977). 



The Apalachicola estuary is a 

 shallow, bar-built system of 549 

 km , which receives freshwater run- 

 off from a 7,530 km watershed in 

 Florida, Georgia, and Alabama. 

 Average depth of the estuarine sys- 

 tem at mean low tide is 2.7 m. The 

 usual tidal range is 0.5 to 0.7 m. 

 The Apalachicola River, with an 

 average flow rate of 540.7 m /s, 

 provides the major, input. Local 

 runoff from 1,295 km of swamp land 

 also influences the estuary (Living- 

 ston et al. 1974) . 



Apalachicola River flow exhi- 

 bits a long-term cycle, irregular 

 in amplitude and duration, of ap- 

 proximately 5 to 7 years. The 

 cycle is more a function of upriver 

 (Georgia) rainfall than of local 

 (Florida) rainfall (Meeter et al. 

 1979). River flow varies seasonally 

 usually peaking sometime from January 

 to April, with minimal flows during 

 late summer and fall months. The 

 seasonal cycle, like the long-term 

 cycle, is more a function of upriver 

 rainfall than local rainfall (Living- 

 ston et al. 1974) . 



This bay is characterized by 

 low light penetration, considerable 



oyster bar development, and low pri- 

 mary productivity from benthic macro- 

 phytes (Livingston et al. 1978). 

 Although Livingston et al. (1978) re- 

 ported that there usually is little 

 vertical or horizontal variation in 

 temperature, this bay does stratify, 

 and tongues of high-salinity water 

 often extend into the bay along the 

 bottom through passes (Livingston 

 et al. 1974). 



Peak levels of biological acti- 

 vity in this estuary appear to be re- 

 lated to hydrologic events (Sheridan 

 and Livingston 1979). A seasonal 

 succession of dominant fish and in- 

 vertebrate species in the bay seems 

 keyed to the seasonal river-flow pat- 

 tern (Livingston 1976). Maximum in- 

 fluxes of dissolved organics, inor- 

 ganic nutrients, and detritus are 

 associated with periods of peak riv- 

 ver discharge. The numbers of ben- 

 thic infaunal organisms, and the de- 

 mersal fishes and invertebrates that 

 feed upon them, also peak at this 

 time (Sheridan and Livingston 1979). 

 Variations in abundance of different 

 trophic groups appear roughly related 

 to annual fluctuation in river dis- 

 charge. For instance, Atlantic 

 croaker and spot, benthic-feeding 

 fish, reach maximum abundances in 

 years of high river flow (Livingston 

 et al. 1978). 



Annual commercial oyster har- 

 vests were negatively correlated with 

 annual river flow and annual blue 

 crab harvests were positively corre- 

 lated with annual river flow from 

 1957 through 1977 (Meeter et al. 

 1979). A strong negative correla- 

 tion existed between oyster and blue 

 crab landings. Meeter et al. (1979) 

 thought this might indicate an influ- 

 ence on landings of unidentified eco- 

 nomic factors such as catch effort, 

 catch price, and fishing preference. 

 A predator-prey relationship between 



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