70 
THE CALIFORNIAN SALMON. 
they are exposed, are legion. The water may become too 
low, and leave the eggs to perish ; floods may tear up the 
gravel and cover them over with mud ; frogs, lizards, water- 
rats, snakes, and numerous kinds of fish find a dish of ova 
a dainty feast. When the young aalmonoid is hatched 
and reaches the alevin stage, it is equally exposed to perils 
of similar kinds, and at every stage from the ovum to the 
adult salmon, dangers encompass it and snares surround it. 
It is, therefore, easy to see what must be the advantages 
of protecting these delicate and helpless young creatures, 
at least until they are in a measure able to provide for 
their own safety. 
The ova of salmon and trout, when deposited in the 
natural redds , can be collected by using a hoop-net, made 
of fine netting. This should be. held in the current below 
the redd , while the gravel in which the eggs are imbedded 
is turned over with a spade. The gravel falls to the 
bottom immediately, but the ova, being lighter, float a 
little way with the current, and get caught in the net 
and can then be placed in damp moss, and taken to the 
hatching-boxes. It is not very safe to keep them long in 
still water, although they may be retained in this way for 
a short time. It is well to renew the water occasionally, 
or to have it cerated, to prevent injury to the ova. 
But, as collecting the ova from the natural spawning- 
beds is attended with great difficulty, a plan has been 
adopted, of netting the fish when they are ready to 
spawn, and by careful manipulation, obtaining the 
ova from the female, and fertilising them with the 
seminal fluid, taken in the same way from the male. A 
little practical experience teaches the operator, to know 
when a female fish is ripe for spawning ; the eggs having 
then left the ovaries, and descended into the abdomen, 
where they remain ready to flow out with a slight pressure, 
