there were no inherent factors to prevent normal grovvth and developaaenti 

 Finally, the evidence points to the conclusion that a low salinity- 

 level was the single important factor in causing the poor conditions 

 which existed in the oyster population. 



Area III. The gro-vvth, mortality and quality of oysters from Lake 

 Mechant and connecting bayous indicate that this environment was 

 suitable for normal growth and reproduction but that the salinity 

 levels for several months were probably close to the lower limits 

 necessary for the commercial production of oysters. 



SIGNIFICANCE OF PEARL RIVSR DRAINAGE BASIN 



The question then natxirally arises, --why should this area in 

 Mississippi Sound suddenly, i, e. , since the flood of 1945, become 

 either unproductive or have extensive mortalities? According to 

 local oystemen the area under consideration has been in the past 

 the source of some excellent oysters, but we have little evidence 

 as to the rate of production or whether production was maintained 

 every year. The Bonnet Carre Spillway has not operated during the 

 four years, if we except a few days leakage in the latter part of 

 February, 1949. The amount of water entering Lake Pontchartrain 

 at that time was the equivalent of only an over-night rainstorm 

 according to the New Orleans District Engineers. The estimated 

 maximum flowage rate of 1007 second/feet persisted for a very short 

 time. If fresh water from only the Pearl Rivffis the cause, we must 

 assume that either mass mortalities have occasionally occurred in 

 the past or that some recent changes In this drainage basin have 

 taken place. 



For these reasons, an investigation was made of the quantities 

 of water discharged by the Pearl River and its tributaries into 

 Mississippi Sound, The distance from the mouth of the Pearl River 

 to the oyster reefs most carefully studied varies from 4 to 10 

 miles north and west. The Pearl River drainage basin extends 

 some 200 miles due north of the west end of Mississippi Sound 

 and covers more than 8,000 square miles of land within the States 

 of Mississippi and Louisiana, 



Fortunately for our purposes, discharge records have been 

 maintained during the past ten years at Pearl River Basin stations 

 approximately 50 miles up from Mississippi Sound, This means that 

 the discharge rates listed are lower than the amount of fresh 

 water which actually flowed into Mississippi Sound. 



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