20 



active. On densely crowded beds it is very likely that a good 

 many of the eggs would become fertilized in the absence of any 

 currents; but where the oysters are scattered this proportion 

 would be exceedingly small. It is a well-known fact that in 

 regions removed from the influence of currents the reproductive 

 capacity of tlie beds is much lower than on beds that are exposed 

 to active currents. 



After fertilization has been accomplished the currents are 

 the chief agents in the dissemination of the fry. The fry is a 

 free-swimming organism; but its powers of locomotion are not 

 sufficient to carry it any great distance from the point of its 

 origin. The wider the distribution of the fry the greater will 

 be the chance that any one of them will have an opportunity to 

 come in contact with some hard body to which it can become 

 attached when it is ready to settle down to its fixed mode oi' 

 life. Even strong currents do not seem to prevent the fry from 

 settling on any suitable object which may be exposed in the 

 water, and frequently where the current is the strongest the 

 set of spat will be heaviest. 



SILT, MUD AND SUSPENDED MATTER. 



A large amount of sediment in the water is a great draw- 

 back to the successful pursuit of oyster culture in any region. 

 The organisms which make up the food of the oyster are found 

 suspended in the water, and, of course, this material 'cannot be 

 looked upon as disadvantageous. An ideal condition of the 

 water would be where there was an abundance of the food 

 organisms without any inorganic matter suspended. The pres- 

 ence of sediment which will be deposited on any hard body on 

 the bottom makes the planting of clutch a very uncertain un- 

 dertaking, and is also likely to cause a great loss among small 

 oysters which have been planted for seed. 



An organic slime is sometimes formed on shells and other 

 hard bodies in the water. This deposit is found most frequently 

 on the shells of a bed which is exposed to the air for a part of 

 the time each day. as in the case of the reefs of "coon" oysters 

 that are fo^iiid in the marshes alono- the coast. The slime is 

 usually made np of a growth of some of the small algae auJ 

 forms an effectual barrier to the setting of spat on the shells 

 which it covers. 



