1 88 THE OYSTER. 



upon it by us; the third the number of square yards 

 dredged ; the fourth the number of oysters taken ; the 

 fifth the number found by us in 1882 ; the sixth the 

 number found by us in 1883 ; the seventh the amount 

 of deviation from Winslow's average for 1879, f 4 I 9 

 oysters to the square yard, and the eighth the per- 

 centage of gain or loss since the last examination. 

 Thus the first line shows that eight dredgings were 

 made upon the Bodkin; that 1732 square yards were 

 examined; that 894 oysters were obtanied; that the 

 bed had lost ^ oysters to each square yard since 

 1882, and that it has lost 62 per cent of its value in 

 that time. 



RATIO BETWEEN LIVING OYSTERS AND DEAD SHELLS. 



When the oysters are culled upon the beds where 

 they are caught, the dead shells are thrown back, and 

 the oysters upon a bed which has been overworked 

 will therefore form a smaller part of the total contents 

 of the dredge than they will upon a more prosperous 

 and valuable bed. In a dredge which has been hauled 

 over an unexhausted bed, the living oysters are many 

 and the shells are few, while the dredge brings up 

 from an exhausted bed a great mass of rubbish which 

 must be lifted and handled in order to obtain a few 

 oysters. 



The ratio between the living oysters and the dead 

 shells therefore furnishes us with a means for deciding 

 whether a bed is deteriorating or not. This method 

 of estimating the condition of the beds is a very rough 



