78 tT. S. BrRE.A.U OF riSHEEIES 



Table 2. — Daily temperature and salinity of the water at Doboy Island, Ga., 



June to August, 1928 



For observations of salinity, top and bottom samples of water 

 ■were taken twice a day within 30 minutes of exact time of high and 

 low water. All the samples were collected from the end of the dock 

 at Doboy Island; the determinations of salinity computed from 

 hydrometer readings are accurate within ±0.05 per cent. 



The concentration of salts in the Avater around Doboy Island is 

 subject to wide daily fluctuations depending on the stage of the tide. 

 There were but slight differences in the concentration of salts in top 

 and bottom samples, but the diiferences in the salinities of high and 

 low water were large, sometimes reaching 20 points. This fact can 

 be noticed by examining Figure 11, where the daily bottom salini- 

 ties observed at high and low water are plotted. After August 21, 

 due to the rise of the Altamaha River, there was a sharp decline in 

 the salinity, the water remaining fresh until the end of the month. 

 That the drop in salinity at Doboy Island should be attributed to 



