374 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
might thus, it is evident, determine absolutely the time to place collectors and to 
close and open the tide gates. At home all experiments have failed owing to imperfect 
aeration. Efforts to renew the water by supply and drainage currents have led to 
the escape of the embryos; while, if the basin has been entirely closed, its smallness, 
together with accumulations of sediment, has usually resulted in leaving the collector s 
far less covered with spat than if they had been placed in the open water without. 
In Europe artificial fertilization of the flat oyster is impracticable, since the fry are 
retained and incubated by the maternal shell ; hence, in pond culture, there will be 
necessary the troublesome task of introducing, examining, and guarding the spawning 
oysters. 
Experiments by Bouchon-Brandely in 1881 with fertilized eggs of the Portuguese 
oyster are clearly set forth in his report.* The embryos were successfully reared in 
small ponds, but the success was not sufficient to warrant profitable culture. 
Reservation by Government of oyster-bearing tracts. — To the Government as well as 
to the culturist the oyster industry is a profitable one. It is, therefore, state policy 
to foster its development. This it has done most judiciously in the regions of seed 
production. Oyster-bearing tracts centrally located have been staked out and rigor- 
ously guarded to furnish spat for the entire neighborhood. These tracts are intended 
to include all depths of water and all conditions suitable for production. The impor- 
tance of these measures can not be overestimated. Without it seed production would 
become impracticable. Everybody’s business would otherwise become nobody’s busi- 
ness, for the culturists would have a jealous dread of retaining oysters to furnish fry 
for the entire neighborhood. The condition of these reserved grounds becomes a 
matter of great importance. A committee is appointed to represent the different 
estates and to control their management. This committee causes the grounds to be 
regularly examined, and experiments and reports upon questions relating to dredging, , 
cleaning, or replenishing the banks. 
ELEVAGE, OE THE GEOWING OF OYSTEES FOE MAEKET. 
The question of obtaining seed oysters is regarded in France as a certain and not a 
costly affair. The time and expense devoted to the oyster are during its elevage or pro- 
cess of cultivation. The eleveur receives seed oysters which, perhaps, are but the size of 
a finger-nail. He must place them under their most favorable conditions for growth 
and fattening, must care for them, and must in the end send them to a critical market 
as cultivated oysters, perfect in shell, well-fattened, and delicate in flavor. He must, 
therefore, make a study of his locality, to find what conditions are most favorable 
for rapidity of growth or flavoring. His work begins when he receives the freight of 
millions of seed from Arcachon or Auray. These are unpacked, carried down to the 
low- water line, and arranged in the flat wire- gauze rearing cases (Plate lxxii, Fig. 2). 
These he regards as important to the industry as the tile itself, for in the first place 
the cage lifts from the bottom and prevents the young from being stifled by the shift- 
ings of mud; it renders the growth regular and rapid, and above all it protects the 
oysters from their enemies — crabs, boring snails, and starfish. The mortality of 
oysters during the three years of their elevage may by case culture be reduced as low 
as 10 per cent. 
V. ref. 9, e. 
