THE STURGEONS AND STURGEON INDUSTRIES. 
273 
probably have to be very vigilant in their attention to the eggs in order to keep the 
fungns under control. 
Themethodof incubating theeggs upon trays of cheese-cloth, will enable the attend- 
ants to readily handle the attached eggs in shallow troughs of running water, and in a 
good light all the dead eggs or those with any fuugus attached may be very readily 
removed. With close attention to the details of the work of propagation very impor- 
tant results might be attained and the work of restocking the Delaware and other 
streams might be undertaken with a very fair prospect of success. This view I think 
may be assumed as fully warranted when it is remembered that as many as 800,000 eggs 
may be obtained from a single fish. These would cover fifty trays measuring 12 by 
18 inches, or about 75 square feet of surface. 
This large number of trays might be operated in a small space in troughs aboard 
a vessel adapted to fish-hatching or the trays might be placed in wire cages to keep 
out predaceous fishes, insects, etc., and partly sunk into the water in such a place as 
the fresh water iiool near the caual lock at Delaware City. With a small pumping 
engine the supplies of fresh water might be supplied for the purpose of cleaning and 
overhauling the eggs in a small building near by which might be provided at a slight 
expense for this purpose. 
13. OBTAINING THE EGGS. 
The best source of supply for eggs the writer has found to be the live fish which 
are brought to the Delaware City butchering floats, directly from the gill-nets. These 
fish, if they have been handled with a slight amount of care, will be found alive and 
in condition to yield living spawn. Two precautions may be taken by the fishermen 
which will be of great service in keeping the fish alive in the boat. These are to cover 
them so as to keep the sun off, and to occasionally sprinkle the head with water to 
keep the gills wetted. . As an iuducement to the fishermen to take extra precautions 
with the fish it might be found expedient to offer them the same compensation for a 
fish with good ripe roe, suitable for fertilization, as they could get for a hard roe from 
the dealers in caviare. In order to get the male fish in good condition it might be 
well to offer an equal consideration for a male with flowing milt. Fishes of either sex 
would then be handled by the fishermen with such care as to aid largely in guaran- 
tying the availability of their spawn. 
It has also been suggested that the spawning fish be “haltered.” The haltering is 
accomplished by passing a rope through the mouth and gills and tying the animal to 
a boom or post near the shore. The difficulty in that case is the ease with which 
lampreys and eels attack the sturgeon; besides, it is said that the eggs of such fishes 
as have been haltered or kept in confinement become valueless for purposes of fertil- 
ization. Such, at least, has been the experience of the Eussian investigators who 
have nndertaken to obtain their supplies of embryo from fishes kept in confinement. 
It is probable that the eggs of the sturgeon, as has been found in the case of the clupe- 
oids or herrings, when kept in confinement, become disorganized and incapable of fer- 
tilization. In the case of certain members of the herring family, the mature eggs of 
fishes kept in confinement undergo such changes of disorganization as to be readily 
noticeable under the microscope. This singular effect of confinement upon the ripe 
eggs in the roes of fishes has been supposed to be due to fright. Such an explanation 
Bull. U. S. F. C., 88 18 
