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During the winter of 1993 1994, we characterized habitats used by 17 radio-tagged largemouth bass Micropterus salmoides in La Grange Reach of the Illinois River, a large river-floodplain ecosystem that has been significantly altered from its natural state. Radio-tagged largemouth bass wintered in backwaters, off-channel coves, ditches, and marinas from November through February. Electrofishing mean catch rates were higher in the study areas during winter than in other seasons, indicating fish were more concentrated in these areas during winter. Five of nine study areas received thermal inputs from springs or power plants, but water temperatures in all nine areas were warmer than the main channel during winter. Current...
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Little is known about the population dynamics of largemouth bass Micropterus salmoides in temperate large river floodplain ecosystems. However, the hydrological regimes in these systems are often similar to those of large reservoirs where fluctuating water levels during spawning have been shown to affect largemouth bass population dynamics. Most backwater lakes of the Illinois River have soft, silty substrates. These substrates are not conducive to nest building, so spawning centrarchids may use annual spring floods to access inundated terrestrial vegetation and previously dry, compacted substrates on the floodplain. We used electrofishing catch data from La Grange Reach of the Illinois River (1990 1995) to assess...
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The Long Term Resource Monitoring Program (LTRMP) completed 2,653 collections of fishes from stratified random and permanently fixed sampling locations in six study reaches of the Upper Mississippi River System during 1991. Collection methods included day and night electrofishing, hoop netting, fyke netting (two net sizes), gill netting, seining, and trawling in select aquatic area classes. The six LTRMP study reaches are Pools 4 (excluding Lake Pepin), 8, 13, and 26 of the Upper Mississippi River, an unimpounded reach of the Mississippi River near Cape Girardeau, Missouri and the La Grange Pool of the Illinois River. A total of 61 79 fish species were detected in each study reach. For each of the six LTRMP study...
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