HIGHLIGHTS FROM 14 YEARS OF FISH MONITORING ON POOL 26 OF THE MISSISSIPPI RIVER.

Eric N. Ratcliff, Eric J Gittinger, and John H. Chick.
Great Rivers Field Station, Illinois Natural History Survey, 8450 Montclair 
Avenue, Brighton, IL 62012.

Staff of the Great Rivers Field Station have been collecting fish data on Pool 
26 of the Mississippi River as part of the Long Term Resource Monitoring Program 
(LTRMP) since 1989. We analyzed Pool 26 fish data to determine the major 
population trends for the period of 1989-2002.  A major event during this time 
period was the Great Flood of 1993.  This flood allowed several fishes to 
produce exceptionally strong year classes, including common carp (Cyprinus 
carpio), largemouth bass (Micropterus salmoides), and black crappie (Pomoxis 
nigromaculatus).  The flood of 1993 also eliminated most aquatic vegetation in 
our pool, and populations of most Centrarchids declined following 1993.  In 
recent years, these species have started to rebound, and other species have 
become established in our pool. Bighead (Aristichthys nobilis) and silver 
(Hypophthalmichthys molitrix) carp appeared in our data in low numbers until 
1998 when production of young of the year fish indicated they became 
established.  Since the mid 1990's, populations of these two invasive species 
have increased exponentially.  Blue catfish (Ictalurus furcatus) were a very 
minor portion of the LTRMP catch in Pool 26 throughout the 1990’s, but began 
increasing in 2000 and had strong year classes in 2001 and 2002.  Channel 
catfish (Ictalurus punctatus) also produced a strong year class in 2001.  Our 
fish monitoring data suggest that we are in a particularly dynamic period of 
time, and the continuation of our LTRMP sampling will be important for tracking 
changes in the fish community. 

Keywords: Mississippi River, LTRMP, Pool 26, Great Flood of 1993, population 
trends.