exist in 

 flushing. 



river flow and tidal 



A review of Charlotte Harbor 

 characteristics and adjacent bodies 

 of water can be found in Taylor 

 (1974). Information on fishes in the 

 specific area of this study can be 

 found in Finucane (1966), and Wang 

 and Raney (1971). Both studies des- 

 cribe seasonality and general fish 

 community composition. Each study 

 noted that decreasing abundance 

 occurred with decreasing salinity as 

 a result of high flows. Wang and 

 Raney (1971) also noted the apparent 

 influence of low temperature decreas- 

 ing abundance in the winter. Their 

 survey data show that the location of 

 this study site is representative of 

 the upper third of the harbor. 



This project was funded by 

 General Development Corporation, 

 Miami, Florida, as part of on-going 

 studies of the aquatic biota, water 

 quantity and water quality issues for 

 Charlotte Harbor. 



Since freshwater flow is sea- 

 sonal in Florida, the data are 

 divided into dry season (October-May) 

 and wet season (June-September) 

 (Bradley 1972). Dry season rainfall 

 is usually the result of cold fronts 

 sweeping in from the north, while wet 

 season rainfall is the result of 

 local convective thunderstorms 

 usually influenced by the position 

 and strength of the "Bermuda high 

 pressure system" in the Atlantic 

 Ocean, providing an easterly flow of 

 moisture across the state. 



Tidal information was based on 

 the NOAA tide tables for 1971-1980. 

 One ebb tide each day was chosen on 

 the basis of greatest predicted range 

 and examined for long-term variation 

 in the average yearly range. The 

 analysis assumed no effects by cli- 

 matic conditions (wind speed and 

 direction) or by high freshwater dis- 

 charge . 



3 

 Cubic meters per second (m /s) is 



converted to cubic feet per second 



(cfs) by multiplying by 35.31. 



METHODS 



RESULTS AND DISCUSSION 



Eight, two-minute repetitive 16- 

 foot otter trawls were taken around 

 Marker #1 (26°56.63'N, 82°03.60'W) in 

 upper Charlotte Harbor about once a 

 month to collect fishes and inverte- 

 brates from bottom depths of 3. 5-4. 5m 

 at night after twilight. The net was 

 5/8-inch mesh with 3/16-inch Ace mesh 

 lining the bag and was towed at 1100 

 rpms by a 7.3m boat. Timing of the 

 trawl commenced when the line reached 

 51m. In situ water column profile 

 data were taken at 0.5m intervals 

 for temperature, salinity, dissolved 

 oxygen, pH and redox potential 

 just before the series of trawls. 

 Peace River flow was taken from 

 the USGS station at Arcadia, 

 Florida . 



PEACE RIVER FLOWS 



About 70 percent of all fresh 

 water measured at USGS gauging 

 stations to Charlotte Harbor passed 

 Arcadia, Florida during this study. 

 Peace River flow is highly variable 

 both within a particular year and be- 

 tween years. During the 49 years of 

 record, annual mean flow ranged from 

 11.01 m /s in 1956 to 72.81 m /s in 

 1960, an increase of over six-fold in 

 a 5-year period. While it may be 

 fortuitous that the high and low 

 records for 49 years occur within 

 the same 5-year period, it dramati- 

 cally illustrates changes in flow 

 which can occur from year to year. 



297 



