OYSTER BOTTOMS OF MISSISSIPPI EAST OF BILOXI. 



31 



or otlierwise inferior character of the oysters produced. The effects, 

 of the salinity 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 thrive 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 fok 

 lowing table summarizes the results of these observations: 



Specific Gravity of Water at Various Places and Dates. 



Locality. 



Ofl Point aux Chenes. 

 Pascagoula, Miss...... 



Three mUes south of Graveline Bayou . 



Three miles off Biloxi Bay 



Three miles southwest of Deer Island . . 



1910-n 



Feb.!>-ll 



Feb. 14-16.... 

 Dec. 24-27.... 

 Jan. 20-24.... 

 Jan. 29-31.... 



Feb. 1-4 



Feb. 5-8 



Feb. 12-14.... 



Mar. &-8 



Apr. 2^ 



Feb. 16-18 



Mar. 13-14 



Feb. 19 , 



Mar. 4-6 , 



Mar. 8 , 



Mar. 11-13 



Feb. 20-23.... 

 Feb. 24-27.... 

 Feb. 28-Mar.3 

 Mar. 9-10 



Average 

 tempera- 

 ture. 



Average 

 specifle 

 gravity. 



1.0190 

 1.0170 

 1.0196 

 1.0122 

 1.0169 

 1.0121 

 1.0136 

 1.0136 

 1.0168 

 1.0152 

 1.0175 

 1.0209 

 1.0178 

 1.0189 

 1.0193 

 1.0193 

 1.0151 

 1.0150 

 1.0170 

 1.0187 



Maximum 

 specific 

 gravity. 



1.0204 

 1.0194 

 1.0209 

 1.0154 

 1.0188 

 1.0156 

 1.0173 

 I.OISO 

 1.0178 

 1.0190 

 1.0194 

 1.0210 

 1.0207 

 1.0196 

 1.0212 

 1.0203 

 1.0177 

 1.0156 

 1.0186 

 1.0192 



Minimum 

 specific 

 gravity. 



1.0164 

 1.0129 

 1.0187 

 1.0109 

 1.01.52 

 1.006:i 

 1.0073. 

 1.0084 

 1.013a 

 1.0140 

 1.0133 

 1.0203 

 1.013a 

 1.0182 

 l.OlSi 

 1. 0187 



i.oiia 



1.012» 

 1.0127 

 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 \vith 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 mmimum 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. 



