Though it is possible to purchase a certain number of salmon ova, this
is not at all a satisfactory way of obtaining them. To begin with, it is
impossible to get them in sufficient numbers to carry out operations on
a large enough scale. Salmon ova are also expensive; and it is no use
working with less than half a million in several stations if the river
is of any size. It is advisable that the ova should be obtained from the
fish. This may be done either by collecting the ova deposited by the
fish in the spawning beds or from the gravid females. The latter course
necessitates the ripe female and male fish being caught and artificially
spawned. As in nature, at best but a comparatively small percentage of
the ova are impregnated, and by artificial spawning over ninety per
cent. of them may be successfully hatched out, there can be but little
doubt as to which is the better way. It is difficult to make sure of
catching the fish just at the time they are ripe, so it is advisable to
impound them in a fenced-off portion of the river, where they may be got
at easily.
In the ripe female the ova flow out very readily, and but little
pressure is necessary. Hard pressure on the abdomen should never be
applied, as it is sure to injure the fish. A ripe female having been
obtained, from which the ova flow readily, the female is held over a
perfectly clean tin or earthenware dish--wet, but containing no
water--and the ova are caused to flow into it by gently but firmly
pressing the hand on the abdomen, and stroking it down towards the vent.
Milt from a ripe male fish is then allowed to run over the ova in the
dish, and is made to run well between them by tilting the dish about
from side to side. The ova will now adhere together, and some water
should be added. This water should be poured off and fresh added till
the superfluous milt is washed away, when the ova should be left in the
water till they separate, which will be in about twenty minutes or half
an hour.
The fertilized ova thus obtained may either be laid down in artificially
protected hatching beds, or may be transferred to a hatchery. The latter
proceeding, of course, requires a hatching house specially built and
arranged, and as this is outside the scope of the present work, I would
refer my readers to larger works upon the subject, such as _An Angler's
Paradise_, by J. J. Armistead. Of course, by using a hatchery a large
number of the eggs will be saved, ninety per cent. of them should hatch
out. This is, therefore, obviously the best way to proceed. A very much
larger number of eggs will, however, be hatched out in properly-chosen
artificial beds than would be the case if they were left to nature.
Public-domain text, read in full here on John Shaqi.
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