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|Title:||Fish of two dike pools in the Lower Mississippi River|
|Authors:||Environmental and Water Quality Operational Studies (U.S.)|
Nailon, Robert W.
Pennington, C. H.
|Publisher:||Environmental Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
Abstract: Dike structures, designed and installed by the U.S. Army Corps of Engineers in the Lower Mississippi River, can modify river geomorphology, discharge rates, and sediment movements within the river. These changes in the river's characteristics, plus the presence of the dikes themselves, result in shifts in types, sizes, and variety of aquatic habitats on a yearly basis. At low water river stages, isolated dike pools bordered by bars are formed, creating distinct aquatic habitats which are quite variable in size and depth. Fish and water samples collected in two such dike pools as well as from the adjacent river border were used to determine the importance of dike pool habitats to fish communities during a low water period of 1980. Hydrological results indicate that overall differences in water quality were easily distinguishable once stratification began. Surface readings of dissolved oxygen, temperature, and pH were generally higher in the pool habitats than in the main channel. As depth increased, the opposite was true for dissolved oxygen, temperature, and pH. Conductivity at the bottom in the pools during isolation was much higher than in the main channel. Fish population characteristics were similar in the two pools, but were different from those in the river border. Mean catch per effort values were generally greater in pool habitats with all gear types--seines, hoop nets, and electroshocker. Catch in pool habitats was dominated by threadfin shad and gizzard shad in numerical abundance and total biomass, respectively. River border catch was dominated by typical riverine species such as minnows and shiners. The degree of similarity in fish community structure between any pair of habitats was most closely related to their location within the dike field. Condition factors, calculated for blue catfish, were consistently higher in the pool habitats than along the river border. Catch analyses indicated that stone dikes created suitable habitat for the growth and development of many species of fish.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Technical Report|