14 Draft/ Lake Bloomington Management Plan
June 12, 2008
largemouth bass failed to increase the number of bass in the lake. 1 Suitable littoral
2 habitat is needed to bolster game fish populations in Lake Bloomington.
3 Fishing regulations have been used to regulate fishing pressure and the number
4 and size of fish harvested. Lake Bloomington currently has fishing regulations for bass,
5 bluegill, hybrid striped bass, white bass, and crappie. Fishing pressure can be
6 determined from creel surveys and these were conducted in 1996 and 2003. Almost
7 every major game fish showed an increase in catch rates and harvest rates from 1996 to
8 2003. Even though catch rates improved for anglers during the creel surveys, catch
9 rates during the 2007 fish survey did not meet management objectives for most game
10 fish. Only the catch rate for largemouth bass met the management objective.
11 Money Creek was surveyed by IDNR during intensive basin surveys four times
12 between 1987 and 2005 (Table 1). The number of fish species collected ranged from
13 13 in 2000 to 19 in 2005. Carp, quillback, and bluegill were collected in 2005 and not
14 during the previous surveys. These species are found in Lake Bloomington and will
15 move from the lake upstream into Money Creek. Catch rates for spotfin shiner,
16 orangethroat darter, and fantail darter have declined over the 4 surveys. These species
17 are indicators of good habitat and water quality.
18 The Index of Biotic Integrity (IBI) was developed to assess the quality of streams
19 using fish species collected during surveys (Smogor 2000). The IBI score is based on
20 10 matrices that were developed for different regions across Illinois. With each region
21 comprising a unique set of matrices, the IBI score better reflects the effect of human
22 disturbance on fish. The IBI scores obtained during the intensive basin surveys ranged
23 from 24 to 30 (Table 1). The highest score obtainable is 60. The score of 60
24 represents a stream that has characteristics of the benchmark conditions set to develop
25 the IBI. The benchmark conditions reflect the biological conditions expected in Illinois
26 streams least disturbed by human impacts. Therefore, the degree to which an IBI score
27 deviates from the maximum score reflects the relative amount of human impact
28 additional to that already represented by the reference conditions. The developers of
29 the Illinois IBI suggested that a score difference of 10 or less should not be interpreted
30 as a meaningful difference in biotic integrity (Smogor 2003). The IBI scores of 24 to 30
31 put Money Creek into the low category of biotic integrity (Table 2). Only minor changes
32 in a few fish species can be seen from 1987 to 2005, which has kept the biotic integrity
33 of Money Creek low.
Table 2: IBI score description
IBI-Score Biotic Description of Typical Biological, Physical, and
