The waters of the western Mississippi Sound are usually turbido 

 The degree of turbidity depends on wind effects in creating turbulence 

 on the bottom and/or the silt load in the waters brought into the 

 area during flood stages of the rivers© Turbid conditions were 

 present during most of the period of our observations j, February 11 

 through 23o Most of this time the turbulence of the water from 

 th© high winds roiled the bottom and put into temporary suspension 

 the loose silt usually present in the area© This occurs many 

 times throughout the year and the extent of its deleteriousness 

 on oysters is debatable© Heavy silting, however, may be dangerous 

 to oyster populations© 



Some silt was furnished by the influx of the Pearl River flood 

 waters, but this influence was limited to the area not greatly removed 

 from the mouth pf that River© The silting pattern from the Pearl 

 River was observed from the air and its limits were well defined© 

 The margin of this silt line extended or contracted according to 

 the direction of the winds. Winds from the north pushed the silt-laden 

 river water southerly as far as Grand Island© Winds from the south 

 restricted the silted waters to the immediate area around the mouth 

 of the River© The silt load contributed by the Pearl River at this 

 time did not seem excessive© 



The drainap;e of Lake Pontchartrain through the Rigolets into 

 western Mississippi Sound was not carrying silt at the time of 

 these observations© The silt from the Mississippi River entering 

 Lake Pontchartrain through Bonnet Carre Spillway was still contained 

 within the Lake© This situation may easily change if westerly winds 

 and flow through the Spillway is prolonged© Mississippi River silt 

 came into Mississippi Sound in quantity in 1945 by this route as 

 recorded by competent observers at the timeo The slow movement of 

 the silt^laden water at present presages little cause for alarm 

 from this source unless more drastic flood conditions on the 

 Mississippi River develcp. 



The condition of oysters and the oyster bottoms both natural and 

 planted likely to be damaged was examined during this survey to serve 

 as a base line for determining future changes o The sampling covered 

 the area that received damage during 1945© Oyster mortalities were 

 generally low (Table 7)© At Grand Island, Station M-7, the boxes of 

 recently dead oysters and the number of bright scars represented about 

 a 30 percent mortality© The proximity of this oyster ground to the 

 mouth of Pearl River, a source of fresh water, may account for most 

 of this loss© This hed would also be in the path of fresh water and 

 silt from the outflow of Lake Pontchartrain© The living oysters at 

 this station were in fairly good condition as they were at all other 

 stations examined© 



