MANUAL OF FISH-CULTURE, 19 



The e^si; receptacles ai-e deep wire trays or baskets about 12 inches 

 wide, 24 inches h^ng, and deep enough to project an inch or two above 

 the water, which is 5 or 6 inches deep in the troughs in which they are 

 placed. Into each of these baskets 2 gallons of salmon eggs, equiva- 

 lent to about 30,000, are poured at a time. The eggs suffer no injury 

 whatever from being packed together in this manner, the water being 

 supplied in a way that forces it through the eggs, partially supporting 

 and circulating through them. The meshes are too small to permit the 

 eggs to pass through, although the fry are able to do so. 



The advantages of this apparatus and method are: 



(1) The top of the tray or basket is out of the water and always 

 entirely dry; consequently, in handling it, the hands are kept dry. 



(2) By tilting one end of the tray up and down a little or by lifting 

 it entirely and settling it gently back again in its place the bad eggs 

 will be forced to the top ; thus a feather is not required in picking over 

 the eggs and the injuries very often inflicted with it are avoided. 



(3) The top of the tray being above water, the eggs can never run 

 over the top nor escape in any way, whicli is a great advantage over 

 the shallow form of tray. 



(4) There is economy of space; 30,000 to 40,000 eggs can be placed 

 in each basket, provided a sufficient quantity of water is available. 

 Two troughs, 16 feet long and 1 foot wide, will by this method carry 

 about 500,000 salmon eggs. The deep trays may be filled at least half 

 full of eggs, and thus ten times as many eggs can be hatched in the 

 same space and with the same suj^ply of water as by the old method. 

 A good but gentle circulation is continually maintained through the 

 eggs. 



(5) The deep-tray system is admirably adapted to getting rid of mud 

 that has collected on the eggs, for all sediment accumulating about 

 them can be easily removed by gently moving the tray uj) and down a 

 few times in the water j but if the deposit of mud on the troughs 

 becomes so excessive as to be unmanageable, a false bottom of wire 

 cloth or perforated zinc can be placed in the troughs at a suitable 

 distance above their real bottom, leaving a space of about 1 or 1^ inches 

 between the wire cloth and the trough bottom. By this means the mnd 

 that comes into the trough will sift down into the space below the wire 

 cloth entirely out of the way of the fish, the movements of the fish 

 themselves helping very much to produce this result. Should the 

 accuumlatiou of mud in the space below the false bottom of the trough 

 become too great, it can easily be sluiced out in various ways. 



When quinnat-salmon eggs are simply to be matured for shipment, 

 hatching-trays with ^ or ^ inch square mesh will answer the purpose, 

 but when the eggs are to be hatched in them, every alternate strand of 

 wire running lengthwise, or, better still, every second and third thread, 

 should be left out in order to form an oblong mesh through which the 

 newly hatched fry, after separating themselves from the unhatched 

 eggs, can escape from the hatching-trays into the troughs below. 



