Fish monitoring by the Long Term Resource Monitoring Program on the Upper Mississippi River System: 1990-1994
Dates
Publication Date
1997-11
Summary
The Long Term Resource Monitoring Program (LTRMP) of the Upper Mississippi River System (UMRS) conducts highly standardized monitoring of fishes in Pools 4, 8, 13, and 26, in a segment of the unimpounded Mississippi River, and in the La Grange Pool of the Illinois River. The mission of the LTRMP is to provide decision makers with information for managing the UMRS as a sustainable large river ecosystem given its multiple-use character. In this report I summarize the initial 5 years of fish monitoring by the LTRMP. This report documents temporal variability that will be critical to interpretation of future events and trends (consistent temporal changes), and documents important spatial patterns. Because 5 years of data can only provide [...]
Summary
The Long Term Resource Monitoring Program (LTRMP) of the Upper Mississippi River System (UMRS)
conducts highly standardized monitoring of fishes in Pools 4, 8, 13, and 26, in a segment of the unimpounded
Mississippi River, and in the La Grange Pool of the Illinois River. The mission of the LTRMP is to provide
decision makers with information for managing the UMRS as a sustainable large river ecosystem given its
multiple-use character. In this report I summarize the initial 5 years of fish monitoring by the LTRMP. This
report documents temporal variability that will be critical to interpretation of future events and trends
(consistent temporal changes), and documents important spatial patterns. Because 5 years of data can only
provide tenuous trend information and because the LTRMP sampling design was changed between 1992 and
1993, trends reported herein must be interpreted cautiously. No evidence of reduction of fish species richness
(number of species) was found from 1990 through 1994 or since recording began in the late 19th century. The
abundance of common carp (Cyprinus carpio), an exotic but commercially harvested species, and sauger
(Stizostedion canadense), a recreationally valuable species, increased dramatically from 1990 through 1994.
Few species declined in abundance. Spatial patterns in the abundance of certain species, including bluegill
(Lepomis macrochirus), largemouth bass (Micropterus salmoides), white crappie (Pomoxis annularis), and
black crappie (Pomoxis nigromaculatus) provide substantial evidence that the availability of backwaters
presently limits the abundance of these species in the open river study reach, to a lesser extent in Pool 26, and
probably elsewhere. This information could be instrumental in identifying the effects of present river
management practices and predicting some biological and economic consequences of future changes in
floodplain composition. No evidence was found that the relatively rare lake sturgeon (Acipenser fulvescens),
shovelnose sturgeon (Scaphirhynchus platorynchus), paddlefish (Polyodon spathula), and blue sucker
(Cycleptus elongatus) declined in abundance from 1990 through 1994. The flood of 1993 provided an
opportunity for skipjack herring (Alosa chrysochloris) to temporarily reenter the uppermost pools of the
Mississippi River.
