November, 1954 
Table 21—Observed reduction in numbers 
of marked largemouth bass of the 1941-1942 
group in Ridge Lake, 1943-1951, and a hypo- 
thetical 50 per cent annual reduction in num- 
bers. 
OBSERVED fue 
ss ceeare Per Centr 
YEAR ners 
1941-1942 REDUCTION 
Group or Bass In NuMBERS 
1943.. 1,500 1,500 
1945..... 496 3 
oA 61 94 
19492... 23 74 
sie. 2. 4 6 
caught by fishermen and the number of 
bass that should have been in the lake 
during the fishing season if there had been 
no unaccountable losses. As such losses 
were undoubtedly occurring throughout 
each fishing season, the actual exploitation 
rates must have been higher than figures 
in the table indicate. This is true par- 
ticularly of the 1941-1943 period when 
the unaccountable loss of bass originally 
placed in the lake was 86.7 per cent. If 
all of this loss had occurred in 1941, the 
exploitation rate in 1942 would have been 
nearly 71 per cent. In any case, the lower 
the unaccountable loss for a 2-year period, 
the nearer the calculated exploitation per- 
centage approaches the true figure. It is 
probable that in the last three biennial 
periods, in which the unaccountable losses 
ranged from 9.7 to 11.1 per cent, the 
calculated exploitation rates are only 
slightly below the true rates. 
The calculated exploitation rates for 
marked largemouth bass at Ridge Lake 
were, for all but a single year, higher 
than the rate of 20 per cent reported by 
Ricker (1942:248) for Shoe Lake, In- 
diana, or the rate of 18.5 per cent re- 
ported by Eschmeyer (1942:109) for 
Norris Reservoir. Exploitation rates re- 
ported by Ricker and Eschmeyer were 
based upon recaptures of tagged fish; like 
the rates for Ridge Lake fish, they were 
based upon numbers of fish, rather than 
weights. Exploitation rates based upon 
weights of bass are usually lower than 
those based upon numbers, because small 
bass are more readily caught than are 
larger ones. 
BENNETT: LARGEMOUTH Bass IN RinpGE LAKE 
267 
It is significant that the two highest 
exploitation rates at Ridge Lake were for 
years in which food was scarce as a re- 
sult of draining operations, table 19. 
Efficiency of Baits 
The natural baits (most of them alive) 
used at Ridge Lake included minnows, 
crayfish, hellgrammites, earthworms, grass- 
hoppers, catalpa worms, worm and spinner 
combinations, and canned shrimp. Min- 
nows and crayfish were by far the most 
efhcient in catching large bass (Durham 
& Bennett 1949:11; 1951:6). For the 
fishing seasons of the period 1942-1949, 
minnows had an average catch rate of one 
desirable bass (10 inches or longer) for 
4.0 man-hours of fishing, and crayfish a 
rate of one desirable bass for 5.3 man- 
hours (Durham & Bennett 1951:6). The 
average catch rates for the other natural 
baits varied from one bass of desirable 
size for 10.5 man-hours to one for 48.3 
man-hours of fishing. Earthworms were 
used for bait a larger number of man- 
hours than were any of the other natural 
baits (2,823 man-hours) ; this bait caught 
55.4 per cent of the bass of less than 10 
inches in length that were taken, but only 
16.5 per cent of the bass of desirable sizes. 
Individual kinds of plugs, spoons, and 
spinners, used with a casting rod and reel 
and fished on eight or more trips, caught 
desirable-sized bass at rates varying be- 
tween one fish per 1.9 hours and one per 
5.7 hours (Durham & Bennett 1951:6). 
These baits were used during 1,607 man- 
hours of fishing and caught 586 bass of 
desirable sizes and 137 smaller ones. More 
bass were caught on underwater plugs 
than on floaters, particularly after the 
month of June, when the surface water 
of the lake was very warm. 
Fly-rod lures accounted for 615 large 
bass and 469 small ones in 1,892 man- 
hours of fishing (Durham & Bennett 
1951:7). More fishermen used cork- 
bodied popping bugs and minnows than 
any other type of bait, and these baits 
were very efficient in catching bass. 
In table 22, the efficiency of natural 
baits can be compared with that of casting- 
rod plugs and fly-rod lures in catching 
bass. Many fishermen using earthworms 
fished primarily for bluegills, but it seems 
