8092

• UCREFRP Catalog Number: 8092
• Author: U.S. Department of the Interior.
• Title: Proceedings of the Symposium on Restoration Planning for the Rivers of the Mississippi River Ecosystem.
• USFW Year: 1993.
• USFW - Doc Type: Washington, D.C.
• Copyright Material: NO

14 BIOLOGICAL REPoRT 19

Table 4. Macroinvertebrate metricsa applied to
sampling stations in the Minnesota River basin.

Community metrics Taxonomic group metries

Richness Functional feeding group
ratio
Number and percent of
mayflies
Number and percent of
caddis flies
Number and percent of
dipterans
Ratio of mayflies,
stoneflies, caddis flies

Shannon-Weaver
Diversity Index
Equitability Index

Community Similarity
Index
Community Loss Index

Macroinvertebrate Biotic
Index

8Plafkin et aI. 1989.

river. The objective of this component of the project
was to assess the level of impairment among
macroinvertebrate communities throughout the
Minnesota River basin.
Benthic macroinvertebrates were collected at 9
stations on the mainstem, 10 major tributaries,
and 22 minor watersheds. Benthic macroinverte-
brate sampling stations coincided with sampling
stations used for other project components.
Sampling gear consisted of hand picking, kick-
nets, and artificial substrate sampling (Hester and
Dendy 1962). Sampling was done in summer and
fall. Replicate samples were taken on some sites
on the mainstem and tributaries.
Eleven metrics are being used to assess the
health of the macroinvertebrate community at
each site (Plafkin et al; 1989). Six metries apply to
the whole community, and the other five apply to
specific taxonomic or functional groups (Table 4).
In addition to the biotic metrics, the habitat quality
of each site was quantified using a Qualitative
Habitat Evaluation Index (QHEI) developed by the
Ohio Environmental Protection Agency (1987).
In the 1989 sampling, chironomids dominated at
the most-downstream location (Henderson, rkm
108) and at the two most-upstream sites (Upper
Sioux, rkm 382; and Lac Qui Parle, rkm 454). At all
other mainstem stations, the communities were
dominated by caddis flies. The most common caddis
fly genus was Hydropsyche spp. Cheumatopsyche
spp. was collected in large numbers at Courtland
(rkm. 216), as was Cyrnellus spp. at Lac Qui Parle.
The most common chironomid genus on the main-
stem was Glyptotendipes, which was collected at all
stations.

Benthic community composition at tributary
sampling sites in 1989 varied more than at main-
stem sites. Caddis flies dominated at five sites,
chironomids at three, and mayflies at two. Other
major insect groups were generally found in higher
proporlions than on the mainstem.
In the 1990 survey, four mainstem sites were
dominated by caddis flies and midges, and one site
was dominated by mayflies. Chironomids again
dominated at Henderson, Upper Sioux, and Lac
Qui Parle. Glyptotendipes spp. was the most abun-
dant midge at five locations.
Community composition of benthos on the tribu-
taries was again more variable than on the main-
stem in the 1990 survey. Caddis flies were domi-
nant at five locations, mayflies at two, and midges
at three locations.
On the basis of richness, diversity, and macroin-
vertebrate biotic indices, the 19 stations on the
mainstem and tributaries were categorized in rela-
tion to the effects of pollution. All stations sampled
in 1989 and 1990 were affected by pollution, as
determined by the three metries listed above (Table
5). Henderson, Upper Sioux, and Lac Qui Parle
were the mainstem stations most affected, while
the Chippewa River was the most affected tribu-
tary.
Comparison of benthic diversity indices with
QHEI indicates a relation between the two in the
tributaries. As QHEI increased, diversity increased
in 1989 and 1990. There was no such relationship
observed in the mainstem sites. Perhaps the main-
stem sites are more affected by variables other than
habitat, with respect to macroinvertebrates.

Fish Physiology

Organic pollutants have the ability to induce
liver mixed-function oxidase activities in fish
(Brown 1976; Melancon et al. 1987). Polychlori-
nated biphenyls have been found in fish from the
Minnesota River by the Minnesota Department of
Health. Levels of PCB's were high enough to issue
consumption advisories for sport-caught fish.
From Granite Falls to the mouth of the river, the
advisory for most fish is one meal per month.
The objective of this component of the study was
to determine if PCB's alone or in combination with
other organic pollutants in the Minnesota River
were sufficient to have a significant effect on fish
liver activities. An additional objective was to com-
pare PCB levels found through arochlor analysis
versUS congener analysis.