324 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



over the platform, and give the fry a better chance to escape without immediately 

 sinking into the ooze below. 



The mean depth of water in the pond and canals ought not to be less than 3^ feet 

 and the bottom of the pond and canals should be cut to the same level, with a view 

 to get the full benefit of the tides. 



The method of operating such a system will now be explained. The pond, X, is 

 supplied with the above specified quantity of good spawning oysters, which at a low 

 estimate ought, at the rate of 50 females per bushel, to yield from 100,000,000,000 to 

 200,000,000,000 of fry during the time the cultch may be in position in the canals. 

 If, however, the oysters were very large selected ones, fully twice as much fry ought 

 to be thrown out by them, or fully 200,000,000,000 to 400,000,000,000. 



This enormous quantity of embryos must, unless it finds some objects to which to 

 attach itself, be irrevocably lost. In order, therefore, to provide it with a nidus for 



:^T 



L-i.- 



Cut 6. — Receptacle for cultch. 



the purpose of fixation, an extensive system of collectors is provided in the chan- 

 nel, s. These are figured in detail above, the first being an end and the second a 

 side view and the third a plan. These are essentially flat baskets, with wooden 

 ends, and with the bottoms and sides formed of a very coarse kind of galvanized 

 iron wire netting with 1 to 1^ inch mesh. At the top they are open, and on either 

 side a strong strip or scantling is secured and projects out past the ends of the box 

 or receptacle, to afibrd a means of supporting the whole upon scantling or ledges 

 secured near the 'tops of the sides of the canals, s. These projections of the strips 

 are also intended to afford handles by which two men may lift and move the 

 apparatus about. The uprights at the ends and the horizontal crossbars are intended 

 to enable the culturist to vibrate the box and its contents in the water of the 

 canal without lifting it out, and in such a way as to wash oif any injurious accu- 

 mulation of sediment not swept away by the action of the jetties presently to be 

 described. 



