THE STUEGEONS AND STURGEON INDUSTEIES. 
267 
The upward movements of the schools seem to be affected to some extent by a 
rise of the prevalent temperature of the water aud air, thus making the fishiug for the 
time more profitable. Conversely, a decline in the prevailing temperature is ofteu 
apparently followed by a diminution in the numbers of fish on their way up the river, 
and a cold, late season retards the appearance of the fish from the salt waters farther 
south. A very rainy season, which has caused an unusually abundant flow of fresh 
water down the river, also interferes with their early appearance in the waters above 
Delaware City. This is supposed to be due to the fact that the water becomes fresh 
farther south than usual where the schools then remain to discharge their spawn. 
The fishing season at Delaware City is at its height during the months of May and 
June, but fish are caught during the summer and autumn and until as late as Sep- 
tember and October. 
The spawning fish or “runners” (those with the eggs set free from the ovarian 
follicles and lying loose in the abdominal cavity) are usually most abundant about 
the middle or end of a “run” or school of fish. The period during which the most 
spawning fish have been observed at Delaware City is during the month of May, 
especially the last half of the month. It is then that the greatest success may be 
looked for in getting the eggs for purposes of artificial incubation in large enough 
quantities to make such an enterprise important from an economical point of view. 
The young sturgeons, which are found in certain places in the river in such num- 
bers as to be a great annoyance to the shad and herring fishermen, in whose nets 
they become entangled, are found mostly over certain kinds of rather firm bottom 
not far from the shore, where they may be supposed to feed, and where they are 
known to pass the greater part of the year. In none of the young sharp-nosed forms 
of A. sturio have I been able to find any evidence of a fully developed roe or milt, 
and I infer that the anadromous or migratory habit is probably not developed until 
the reproductive powers are fully matured, when the migratory impulse assumes 
control of the movements of the animal. The young immature fish have been taken 
from under the ice in the river in mid- winter, indicating that they remain in the fresh 
water the whole year. 
The young of the common sturgeon reaches a length of about 3 feet before it 
begins to lose to a marked degree the sharp or acuminate snout which gives it such 
a characteristic appearance, and which has misled not only naturalists, but fishermen 
also, into the belief that these sharp-snouted forms were a distinct species. Natural- 
ists as well as fishermen have bestowed names upon the young fish in the belief that 
they were specifically distinct from the large fishes. 
The mature fishes seek a hard bottom upon which to deposit their spawn in from 
1 to 5 fathoms of water. Except when leaping out of the water aud when moving 
upstream rapidly they do not seem to habitually rise to the surface. The tendency 
of the fish to seek the bottom is taken advantage of by the fishermen in the con- 
struction of their gill-nets, the cork line of which is not made to come to the surface, 
but the wooden floats are attached to cords so as to leave the upper edge of the net 
about a fathom below the surface. The nets of about 300 fathoms length and 3 to 4 
fathoms deep are laid out from sail-boats specially constructed for convenience in 
stowing and liming the net in a slightly raised compartment at the stern. The fishing 
is done during the day-time on the Delaware, each boat being manned by two men, 
whoputout'their net atthe beginning of flood-tide and drift upstream. The net is fished 
