Effects of Water Level Changes on Fishes of the Yazoo River Basin, Mississippi

摘要

The effects of surface water withdrawal on habitat availability and quality were investigated in one lacustrine (Mossy Lake) and various river habitats in the Yazoo River Basin during the summer and fall of 1984 for the following fishes: bigmouth buffalo (Ictiobus cyprinellus), smallmouth buffalo (Ictiobus bubalus), common carp (Cyprinus carpio), channel catfish (Ictalurus punctatus), white crappie (Pomoxis annularis), and blacktail shiner (Notropis venustus). Water velocity, water depth, and instream cover types were determined at river sites where fishes were collected to develop utilization indexes for adult and juvenile life stages. Hydraulic models from the US Fish and Wildlife Service (USFWS) Instream Flow Incremental Methodology (IFIM) were coupled with the indexes to predict quantities of usable habitat for target species at various discharges. In large and medium-sixed rivers it was determined that surface water removal would increase available habitat for species since current velocities would usually decrease and allow fish to utilize a greater percentage of the river. Small rivers would be adversely affected since diminished water levels would reduce cover availabiltiy and limit space for feeding and resting. It was determined that dissoved oxygen levels are adequate at normal flow but often decrease following heavy rain because of elevated biological oxygen demand. Based on regression equations developed from data collected on Mossy Lake, it was determined that withdrawing more than 3 to 4 feet of water from delta lakes would substantially reduce or completely eliminate the sport fishery. (Author)