Table 27. Approximate dimensions of 

 selected estuarine systems (Nixon 1983). 



Estuarine system 



Watershed 

 area (km^) 



Surface Mean 

 area depth 



(kni^) (m) (m) 



Mean Flushing 

 tide factor 



(days) 



Narragansett Bay 

 Long Island Sound 

 New York Bay. 

 Delaware Bay 

 Chesapeake Bay 

 Patuxent Estuary 

 Potomac Estuary 

 Pamlico Estuary 

 Apalachicola Bay 

 Mobile Bay 

 Barataria Bay 

 San Francisco Bay*- 

 Suisun Bay plus 

 San Pablo Bay 

 South Bay 

 Kaneohe Bay 



"Approximate annual 

 freshwater input 



al mean hydraulic residence time. The 

 to Barataria Bay has not been reported. 

 "Below Smyrna River. 

 ■-Area includes mud flats, mean depth = 6 m excluding flats. 



Livingston (1981b), in a comparison 

 of the distribution of various sciaenids 

 in estuaries alonq the northeast Gulf of 

 Mexico, found that the Apalachicola 

 estuary is extremely productive in terms 

 of fish populations (Table 31). Prime 

 habitats include the mud flats of East Bay 

 and the mouth of the Apalachicola River 

 and the grass beds in Apalachicola Bay off 

 St. George Island. The unpolluted, highly 

 turbid estuary, with its high plankton 

 productivity and abundant allochthonous 

 detritus, presents an optimal environment 

 for benthic omnivores (such as croaker and 

 spot) and epibenthic carnivores (such as 

 silver perch and sand seatrout). The 

 Econfina estuary is a relatively clear, 

 unpolluted system dominated by benthic 

 plants (macrophytes), which provide the 

 major source of productivity and habitat 

 features for other organisms in the area. 

 This estuary, which receives considerably 

 less overland runoff than the Apalachicola 

 system, is dominated by fishes associated 

 with the extensive seaqrass beds in the 

 area. Although fish productivity is 

 relatively high, the sciaenids are not as 

 well represented and account for only 

 about ?0% percent of the total fish 

 catches over the 9-year sampling period. 



The Fenholloway estuary, polluted for 

 over 20 years by pulpmill effluents, is 



Table 28. Estimates of particulate pri- 

 mary production in various estuaries in 

 the United States (after Nixon 1983). 



Location 



Primary production 

 g C m"'' y"l 



^Below Leipsic River, 80^ of total bay 

 production. 

 ''Four-year mean (1«574-1Q77). 

 •^Phytoplankton 165, Benthos 195. 



largely devoid of benthic plants and has 

 an increase in phytoplankton productivity 

 and associated planktonic food webs. 

 Relatively high levels of phytoplankton 

 productivity (derived from anthropoaenic 

 input of nutrients) are correlated with 

 increased reoresentation by fishes 

 associated with planktonic food webs. 

 Overall fish productivity has been 

 severely reduced because of the impact of 

 the pulpmill effluents on the biological 

 organization of the estuary. Although the 

 overall abundance is low, sciaenids are 

 well represented in terms of numbers of 



113 



