42 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
came to any good, the others being destroyed by the fighting of the males. Ordi- 
narily but one or two nests were built in eacli spawning pond. The male first to 
enter and begin the construction of a nest generally regarded the whole pond as 
his property and held it against those that tried to enter after him. On one occasion 
the male thus holding the pond was attacked by 10 or 20 other males at one time 
and after a long struggle was killed and his nest destroyed. 
The attempt to use small spawning-ponds was then abandoned and all the ponds 
were made of good size and with a central kettle and shallow shore area, as already 
described. The problem now Avas to prevent the fighting of the male fish and the 
consequent destruction of nest and eggs. I finally hit upon remedies for Avhat 
seemed to be the two chief causes of this fighting. I had noticed that in the natural 
water the nests of the small-mouthed bass Avere frequently built against a stone or 
log, so as to be shielded on one side. When so built the nests might be quite close 
together, as near as 4 feet, and the fish did not fight, because they did not see one 
another when on the nest. On the other hand, if a bass nest Avas built where it Avas 
not shielded the bass on that nest would prevent any other bass from building 
within 25 or 30 feet of him. It occurred to me to try to construct artificial nests and 
shield them so that the fish on the nests could not see one another, placing the nests 
so near together as to fully utilize the pond area. 
In the spring, before the spawning season opened, the ponds were drawn doAvn 
so as to expose the shallow terrace along the shore. The terracie was then cleaned to 
a depth of about 2 inches of sediment and vegetation Avhich had accumulated since 
the previous summer. Rectangular nest frames of inch board AA'e re made 2 feet 
square and without bottoms. On two adjacent sides these frames were 4 inches 
high, Avhile on the other sides they Avere 16 inches high. They Avere set AAdiere there 
would be about 2 feet of water when the pond Avas filled, and so placed that the 
corner formed by the junction of the two loAver sides pointed to the center of the 
pond, Avhile the opposite corner, formed by the higher sides, pointed toward shore. 
The frames were set directly on the bottom, not in excavations, and each Avas filled 
with gravel containing sand suitable for nest-building. A board Avas laid diagonally 
across the tAvo higher sides and a heavy stone laid oh this to keep the frame in place. 
The two higher sides form a shield on two sides of the nest, while the board across 
the top affords shade. The frames Avere set in two i-oavs about the pond, parallel 
to the shore line. 
The i-oavs Avere about 6 feet apart and the nests in each row about 25 feet apart, 
alternating with those in the other row. There was thus about one nest to each 100 
square feet of suitable bottom, or in each area of 10 by 10 feet. When the bass 
Avere on the nests no one was able to see any other and the fighting from this cause 
Avas practically eliminated. The number of rows of nests may be increased to three 
or four, or more where the area of shallow water is wide enough. 
The bass selected these nests in preference to any other spawning-ground. 
They cleaned up the gravel and behaved in the nests in every particular as they 
would on natural spawning-grounds. The first time Ave tried these shielded nests 
not a single bass made a nest outside of them, though there Avas plenty of good 
gravel bottom available for this purpose. 
As to the second cause of fighting: In 1900, when these nests Avere first tried, 
from 475 stock fish Ave obtained 315,000 fry and 750 fingerlings. In the season of 
1891 the output Avas very much less and there Avas considerable fighting among the 
