218 Inuinois NATURAL 
cance in the production of superior fishing 
for largemouths, or how to make use of it 
in managing the species. 
There is little reason to doubt that the 
“bonanzas”’ of |: argemouth fishing that are 
experienced occasionally by certain anglers 
in certain locations in certain years have 
stemmed from the development of superior 
populations of largemouths. ‘These popu- 
lations appear usually as a result of a 
relatively high survival of bass spawn 
during a season 2 to + years prior to the 
“bonanza” year. Such spawning success 
may be brought about by stocking a new 
reservoir with a few spawners. 
Under natural conditions, any 
trophe which severely decimates a 
catas- 
fish 
History Survey BULLETIN 
Vol. 26, Art. 2 
population that includes largemouth bass, 
but which allows the survival of a few bass 
spawners along with small numbers of 
adults of other species, will almost always 
be followed by an unusually large pro- 
duction of young bass. Such a phenomenon 
as a severe drought or drawdown, winter- 
kill, abnormal predation, disease, or a com- 
bination of these might severely reduce a 
mixed population of fishes and set the 
stage for the production of a dominant 
bass brood. 
Ridge Lake was stocked with 100 adult 
largemouth bass on April 30 and May 1, 
1941. A few weeks later, a very large 
brood of young was produced. When the 
numerical size of this brood was estimated, 
Fig. 1—Ridge Lake, 
spillway are at the lower end of the lake. 
in the shore-line vegetation on the south bank of the lake. 
aerial 
view toward east. 
The laboratory 
The dam, 
is visible within an 
surface spillway, and tower — 
indentation — 
a 
