waters. This area of 546 km his- 

 torically received drainage from Tay- 

 lor Slough and the southeastern 

 coastal plain and probably had a con- 

 tributing area of around 33 km , 

 little of which now drains to north- 

 ern Florida Bay and its embayments . 



Periodicities of water deliver- 

 ies to the park are thought to differ 

 somewhat from that of the natural 

 systems, and the total quantity de- 

 livered to the park's estuaries may 

 be lower than under natural condi- 

 tions. Salinities in Whitewater Bay 

 are considerably higher now than they 

 were historically (Davis 1980), al- 

 though just how much higher is dif- 

 ficult to say because of the highly 

 variable supra-annual rainfall pat- 

 tern. Northern Florida Bay and its 

 embayments often are hypersaline. 

 The frequency and severity of hyper- 

 saline conditions are thought to have 

 increased, but the changes have not 

 been documented. 



A general decline in fishery 

 harvests in the park has been observ- 

 ed in recent years (Everglades Na- 

 tional Park 1979). Davis (1980) 

 found three significant changes have 

 occurred in the park fisheries in the 

 past 20 years : (1) a shift in age 

 structure in red drum and spotted 

 seatrout toward larger, more mature 

 individuals; (2) consistent trends in 

 catch rates (upward for red drum and 

 downward for spotted seatrout); and 

 (3) marked reductions in year-to-year 

 variability of catch rates for both 

 species. His preliminary analysis 

 suggests that changes in environ- 

 mental conditions related to fresh- 

 water inflow caused the changes in 

 fishery stocks and the nature of 

 the harvest. 



Gordon River-Naples Bay Estuary 



The Gordon River-Naples Bay es- 

 tuary in Collier County on the south- 

 west coast of Florida is an estuary 

 that has had its watershed greatly 

 increased by water-management alter- 

 ations. Formerly three small creeks 

 with a combined watershed area of 26 

 km emptied into this small elongated 

 water body of 5.26 km . The con- 

 struction of the Golden Gate Canal 

 system has increased the effective 

 watershed of this estuary to 260 km , 

 ten times the original size. Average 

 maximum monthly discharge, which was 

 approximately 2 m /s under natural 

 conditions, has increased to approx- 

 imately 44 m /s, approximately 20 

 times the predevelopment quantity. 

 Although this estuary, by itself, is 

 too small to greatly affect the fish 

 production of the area, it is one of 

 a multitude of smaller estuaries that 

 makes a general contribution. It is 

 mentioned in this report mainly be- 

 cause its problems are representative 

 of those in other areas and the ap- 

 proach made to evaluation and solu- 

 tion of these problems is both unique 

 and worthy of wider application. 



Studies by the Collier County 

 Conservancy determined the effect of 

 the increased discharge on the hydro- 

 dynamics of the estuary and evaluated 

 the impact on estuarine water quality 

 and aquatic life. Van de Kreeke 

 (1979) found highly stratified con- 

 ditions in most of the estuary, in- 

 cluding a connected system of deadend 

 canals, throughout the summer and 

 fall months, the period of high dis- 

 charges. The stratification, fresh 

 water overlying salt water, inhibited 

 both vertical and horizontal mixing. 



Hicks (1979a) found that the 

 lack of mixing caused low levels of 



408 



