OYSTER BOTTOMS OF MISSISSIPPI EAST OF BILOXI. 



31 



or otherwise inferior character of the oysters produced. The effects 

 of the saliiiity of the water are not restricted to the direct influence 

 on the oysters, but may affect them indirectly by furthering or retard- 

 ing the occurrence of enemies and growths inimical to them. The 

 conch, or drill, for instance, does not tlirive in water having a low 

 salt content, while, on the contrary, mussels, the vigorous growth 

 of which is highly detrimental to oysters, often flourish in low 

 salinities. 



During the survey the specific gravity of the water was tested thrice 

 daily on the Fish Hawk and in addition several observations were 

 made each day by the party actually working on the beds. The fol- 

 lowing table summarizes the results of these observations: 



Specific Gravity of Water at Various Places and Dates. 







Average 



Average 



Maximum 



Minimum 



Locality. 



Date. 



tempera- 



specific 



specific 



specific 







ture. 



gravity. 



gravity. 



gravity. 





1910-11 



"F. 









Off Point aux Chenes 



Feb. 9-11 



Feb. 14-16 



63 

 67 



1.0190 

 1.0170 



1.0204 

 1.0194 



1 0164 





1.0129 



Pascagoula, Miss 



Dec. 24-27 



49 



1.0196 



1.0209 



1.0187 





Jan. 20-24 



61 



1.0122 



1.0154 



1. 0106 





Jan. 29-31 



65 



1.0169 



1.0188 



1.0152 





Feb. 1-4 



67 



1.0121 



1.01.56 



1.0063 





Feb. 5-8 



71 



1.0136 



1.0173 



1.0075 





Feb. 12-14 



61 



1.0136 



1.0180 



1.0084 





Mar. &-8 



66 



1.0168 



3.0178 



1. 0139 





Apr. 2-4 



70 



1.0152 



1.0190 



1.0140 



Three miles south of Grayeline Bayou 



Feb. 16-18 



68 



1. 0175 



1.0194 



1.0133 





Mar. 13-14 



65 



1. 0209 



L0210 



1.0208 



Three miles off Biloxi Bay 



Feb. 19 



70 



1.0178 



1.0207 



1.0138 



Three miles southwest of Deer Island 



Mar. 4-6 



63 



1.0189 



1.0198 



1.0182 





Mar. 8 



69 

 71 



1.0198 

 1.0193 



1.0212 

 1. 0203 



1 0184 





Mar. 11-13 



1.0187 



Biloxi 



Feb. 20-23 



Feb. 24-27 



54 

 58 



1.0151 

 1.0150 



1.0177 

 1.0156 



1.0118 





1.0129 





Feb. 28-Mar. 3. 



63 



1.0170 



1.0186 



1.0127 





Mar. 9-10 



68 



1.0187 



1,0192 



1.0182 



This table embraces observations made at intervals between De- 

 cember 24, 1910, and April 4, 1911, part of the period, from January 

 20 to March 10, being covered with practically no interruption. 

 During this time the specific gravity varied from^a maximum of 

 1.0210 off the mouth of Graveline Bay on March 14 to a minimum of 

 1.0063 at Pascagoula on February 4, and the local averages for 

 periods of several days ranged with time or place between 1 .0209 off 

 Graveline Bayou on March 13 and 14 to 1.0121 at Pascagoula on 

 February 1 to February 4. These figures compare with fresh water 

 as 1.0000 and ocean water as 1.0250 or 1.0260. The minima shown 

 in the table all occurred at low water and the maxima at or near high 

 water. The lowest readings were taken in Pascagoula River, the 

 station being located at the railroad bridge, where there was a con- 

 siderable difference between the salinity of successive high and low 

 waters. The highest average, as well as the lowest daily fluctuation. 

 77630°— 13 3 



