PACIFIC SALMON FISHERIES. 209 
necessarily ascend through the tray of eggs. The troughs are provided with canvas 
covers stretched upon light frames and made sunlight proof by saturation with 
asphaltum varnish, and their interiors are thickly coated with asphaltum. 
The egg receptacles are wire trays or baskets about 12 inches wide, 24 inches long, 
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, equivalent 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; con- 
sequ2ntly,-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, which 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 10 times as many eggs can be hatched in 
the same space and with the same supply 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 col- 
lected on the eggs, for all sediment accumulating about them can be easily removed 
by gently moving the tray up and down a few times in the water; 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 14 inches between the wire cloth and 
the trough bottom. By this means the mud 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 accus 
mulation of mud in the space below the falsé 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 one-fourth or one-fifth 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-hatehed fry, after separating themselves from 
the unhatched eggs, can escape from the hatching trays into the trough below. 
At Baird eggs kept in water averaging about 54° F. hatch in 35 days. The allowance 
of 5 days’ difference in the time of hatching for each degree of change in the water 
temperature is approximately correct. 
For the first few days the eggs of the quinnat salmon are very hardy, and at this 
time they should be thoroughly picked over and the dead ones removed as far as 
possible before the delicate stage during the formation of the spinal column comes on, 
so that during that critical period they may be left in perfect quiet. As soon as the 
spinal column and the head show plainly, the eggs are hardy enough to ship, but when 
there is time enough it is better to wait a day or two until the eye-spot is distinctly 
visible, after which time the eggs will stand handling and may be safely shipped if 
properly packed. 
