· In 2001, the Indiana University Southeast Ecology Class conducted studies
at three established field sites on Blue River, a southern Indiana tributary of
the Ohio River, known statewide for swift riffles, large populations of
endangered darters and the endangered hellbender salamander.
· Blue River is the best example of a natural and scenic river remaining in
southern Indiana.
· This study was a continuation and evaluation of similar studies conducted at
the same sites since 1995.
· Rapid bioassessment protocols and other field ecology methods were used to
analyze riffle fishes, macroinvertebrate populations, overall habitat, riparian
vegetation and water quality.
· The three sites were permanent darter monitoring sites located below Milltown
Dam, above Rothrock’s Dam, and below White Cloud Dam.
· Using a Zippin removal depletion method, we collected 205 fish representing
11?? species at the three sites.
· During the sampling periods, greenside and rainbow darters outnumbered spotted
darters for the first time.
· Bluebreast darter estimates remained extremely low with only one specimen
taken below Milltown Dam.
· The lowered numbers of bluebreast darters may be related to the alteration of
the dams at White Cloud and Rothrock’s Dam.
· Previous food studies of bluebreast darters indicated that dipterans like
blackfly larvae were their preferred food items.
· Macroinvertebrate assessments revealed that all sites had increased values
when compared with 1995.
· The most dramatic changes were found at Rothrock’s Dam and Milltown where
values moved into the nonimpaired range.
· White Cloud Dam values increased slightly and remained in the nonimpaired
range.
· These increased values may be related to the more efficient sewage treatment
system at Salem and the continued use of reduced tillage agricultural methods.
· Similarity and diversity analyses of the macroinvertebrate communities
indicated that communities have remained very similar over time.
· The stonefly family Pteronarcidae, a shredder, is conspicuously absent from
the recent samples.
· Site species diversity remained stable with only a slight reduction at all
sites.
· Habitat assessment strategies indicated all three sites had ample habitats to
support a variety of aquatic life.
· Old photographs suggest that these habitats, however, have been developed in
the last 15 years.
· The major changes have been dam removal and alteration to facilitate canoe
passage and accumulation of sediments around existing boulder and cobble
habitats.
· Water quality data fell within the ranges expected for a midwestern stream
flowing in limestone terrain.
· Nitrate and phosphates were elevated during storm discharges.
· Future classes should consider concentrating on resource partitioning in the
riffle systems, a sedimentation study, a periphyton study and monitoring water
quality during peak discharge periods.