[55] OYSTER CULTURE. 807 
By the aid of the sluice-ways and gates in this canal the water can be 
admitted directly into the claires without entering the outer basin at all. 
This could be done in case the outer basin were utilized for the rear- 
ing of mussels and there was danger of the spawn of the mussels enter- 
ing into the claires at the period of reproduction. 
GLA P TROL. 
METHODS OF WORKING THE CLAIRES. 
Now that enough has been said in relation to the apparatus for col- 
lecting the young growth, and the construction of the breeding ponds, 
there remain only a few words to be said concerning the method to be 
followed in commencing and continuing a profitable artificial oyster cul- 
ture. First, it is necessary to construct the breeding-ponds which, for 
the sake of greater precision, we call claires, taking as a basis for their 
extent the proportion of 1,000,000 oysters to the hectare or 100 per 
square meter, a proportion which, if it is desired simply to raise oysters, 
can be carried to 500 or 600 per square meter, or 5 to 6 millions per 
hectare; this is the proportion in the parks of the island of Ré. Dur- 
ing their construction, and in order to stock them as soon as they are 
completed, the young growth is procured by means of the collecting 
apparatus already described, or by some of the other forms, preference 
being given to that which will answer best for transportation, &e., accord- 
ing to the distance to be traversed from the spawning locality to the 
breeding-pond. As six months of time at least must elapse after the 
young growth have become attached to the collectors before they can 
be transported with safety, the two operations, of constructing claires 
and gathering the young, ought to proceed simultaneously.. Itis in June 
that this work should be undertaken in the ocean and a little earlier in 
the Mediterranean. When the claires are finished, and have a layer of 
pure and fresh sea-water over the bottom, the oysters which have been 
brought upon the collectors should be distributed as evenly as possible 
with a shovel, and afterwards arranged by hand, so that they may not 
form piles in certain places, and be entirely wanting over other sections. 
As the oysters should not remain in the same basin during the entire 
period of their growth, and as the young detached from the collectors are 
very small, they ean be easily so arranged that three or four hundred can 
be accommodated upon a square metre of surface, and afterwards, as they 
increase in size, they can be separated, so as to give more room to each. 
The time of this labor should be chosen so as to end, if possible, at the 
period of a spring-tide, in order that the young oysters, placed upon 
strange soil and in strange water, may be promptly refreshed by the 
incoming tide, and covered with a layer of water sufficiently deep to 
