able to withstand prolonged floods. The freshet of 1903 endured 

 so long that the majority of the oysters in the pass were killed. 

 Some of the deeper heds, however, have survived even this year's 

 catastrophe to such an extent that they still yield about half a 

 barrel of edible adults as the result of a hard day's tonging. 



The damage done by the last high water is well illustrated by 

 counts made at various places. In St. John's Bayou, near the 

 head of the pass (see map) three living adults were found among 

 two hundred hinged shells ; one among one hundred hinged shells 

 on reef No. i ; three among two hundred hinged shells on reef 

 No. 2, and one among one hundred shells on reef No. 3. These 

 iigures will give an idea of the destruction caused by the freshet 

 in certain places, but they should not be taken to indicate that 

 the proportion of living oysters to dead ones is the same every- 

 where. In the case of St. John's Bayou, the count was made on 

 those reefs in its mouth which are exposed at low tide. The 

 counts for reefs i, 2 and 3, however, were made at places which 

 could be conveniently reached with a pair of 12-foot tongs and 

 give an accurate estimate of conditions only at that depth. At 

 greater depths the proportion of living to dead is in all likelihood 

 greater. This is not only rendered probable by an experiment 

 to be described later, but is shown by the fact that tongers found 

 it profitable last summer to work beds in from 16 to 20 feet of 

 water. The explanation why a greate r proportion o f oysters has 

 survived at these depths than aflesser ones is found in the rela- 

 tion between the salinity of the water and its depth. Within cer- 

 tain limits salinity increases with depth. At Calcasieu Pass, dif- 

 ferences of .0005 to .0007 were detected between the salinity at 

 the sfirface and that at six feet below, when the two were taken 

 simultaneously. The higher densities at greater depths might 

 be taken advantage of by the culturist, but the areas available 

 over which a degree of salinity permitting survival even during 

 great floods obtains, are either inconveniently located or too 

 small. Were it not for these fluctuations, nothing could be more 

 admirable for oyster cultivation than the average salinity of the 

 water as shown by the records taken in July, August and Sep- 

 tember. These measurements were made almost daily and on 

 many occasions, a number of times daily, so that the averages in 

 the following table are based on a large number of observations.* 



*For a fuU record of densities taken at different places under various conditions 

 ■of tide and wind, see Appendix A. 



