272 
The bass at Ridge Lake seemed to retain 
their wariness during the fall months; 
even though the lake was closed to public 
fishing for 3 weeks or a month or more, 
the rate of catch in postseason test fishing 
operations was only a little better than 
during the summer. However, the bass 
apparently lost their wariness over winter 
and again became vulnerable to the aver- 
age fisherman, 
Ridge Lake was not opened to the pub- 
lic in 1943 and, in 1944, not until the 
second week of August. During this closed 
period, Natural History Survey personnel 
were taking small samples of bass at regu- 
lar intervals. These bass were taken by 
angling (as bass will seldom enter wing 
nets or traps in clear water), and were 
caught at a very high rate (average rate 
about 10 fish per hour). Most of these 
fish were rather small in size, and small 
bass are less wary than are large. But 
preseason fishing for all years, in some of 
which the average size of fish was much 
larger than in others, yielded fish at a very 
high rate. Preseason fishing in 1949 pro- 
duced bass at the rate of nearly 3 pounds 
per man-hour, table 15. 
Our experience with bass has led us to 
believe that there is for each body of 
water a definite level of fishing intensity 
below which bass do not become “edu- 
cated,’ and that it would be possible, in 
artificial ponds and lakes that are pri- 
vately owned, for the owners so to regulate 
the intensity of fishing that small numbers 
of bass could be caught quickly and with 
little effort on the part of unskilled 
anglers. 
What such a fishing intensity would be 
for a given body of water is a question 
that cannot be answered satisfactorily now. 
At Ridge Lake, it has been demonstrated 
that an opening-day fishing pressure of 
between 1.8 and 5.0 man-hours per acre 
concentrated within a 4-hour morning 
period has been followed in the afternoon 
by a rather severe drop in the catch rate 
of bass. 
Probably the most intensive fishing by 
Natural History Survey personnel at 
Ridge Lake was done during the period 
June 1 to 14, inclusive, in 1949, when 
17.75 hours of fishing yielded 50 bass 
weighing 52.49 pounds, table 15. In this 
14-day period, in which the lake was 
Ittinois Narurat History Survey BULLETIN 
Vol. 26, Art. 2 
fished on 9 days, the fishing pressure never 
exceeded 0.36 man-hour per acre for any 
one day, and usually it amounted to about 
0.05 to 0.07 man-hour per acre per day. 
Somewhere below the rate of 1.8 man- 
hours per acre per day lies a range of 
fishing intensity within which bass appar- — 
ently do not develop wariness. ‘This 
range probably is influenced by the num- ~ 
ber of fishing hours per acre per day, by 
the amount of rest between periods of © 
active fishing, and by the size and con- 
formation of the lake basin. Certainly 
any lake owner may discover, after a few ; 
years of experimental fishing, coupled with ! 
a system of complete creel censusing, the — 
approximate fishing intensity at which the 
catch rate for bass begins to fall off in his — 
lake. It is assumed that during this period — 
the lake is managed to maintain a large 
population of bass; otherwise, the testing — 
of various fishing intensities would mean — 
little. $ 
The average length of life of its indi-— 
duals must be considered in the develop- — 
ment of a management program for any — 
species of fish. The largemouth bass is a _ 
relatively long-lived species, so that a bass — 
of desirable size will probably remain — 
available to the angler for a number of 
years. In most broods spawned in Ridge 
Lake, unaccountable losses among the 
medium-sized bass were usually much 
lower than among the bass of less than 
about 0.2 pound or more than about 3.5 
pounds in weight, table 20. In a location 
such as Ridge Lake, where fish may move 
out of the lake, over the spillway, in time — 
of high water, a large part of the un- 
accountable loss among small bass may be 
due to random migration in search of 
better territory. Larimore (1952: 10) 
demonstrated that smallmouth bass in 
streams have definite territorial instincts 
and that the smaller fish have less well- 
defined territories than have the larger 
ones, presumably because the smaller fish 
are less able to hold desirable territories 
There is some evidence (largely in popu- 
lar literature on bass fishing) that indi- 
vidual largemouth bass in lakes have been 
repeatedly recaptured in definite locations 
over periods of time. If the largemouth is 
similar to the smallmouth in territorial 
instincts, it is not difficult to explain the 
movement of small bass out of a lake 
