226 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



adult oyster. From this time on the young oysters are less 

 exposed to danger, but the number of them that reach maturity 

 is very small when compared with the number that perish or 

 are destroyed in one way or another. 



The young oysters when first attached are called "spat"; 

 when a little older this spat, now called "seed," may be trans- 

 planted to new beds, which are stocked in this way. 



FIG. 104. Young (spat) of the west-coast oyster, Ostrea lurida, attached 

 to rock. (Reduced.) 



In some regions clean shells or other "cultch" are distributed 

 over the beds just before the spawning season in order that 

 there may be plenty of clean hard surfaces for the young em- 

 bryos. The oysters are ready for market in from three to five 

 years, and are gathered from their beds by means of long- 

 handled tongs or dredged up by means of dredges and power 



