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David L. Galat

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group of river managers, stakeholders, and scientists met during summer 2005 to design a more naturalized flow regime for the Lower Missouri River (LMOR). The objective was to comply with requirements under the U.S. Endangered Species Act to support reproduction and survival of threatened and endangered species, with emphasis on the endangered pallid sturgeon (Scaphirhynchus albus), while minimizing negative effects to existing social and economic benefits of prevailing river management. Specific hydrograph requirements for pallid sturgeon reproduction are unknown, hence much of the design process was based on features of the natural flow regime. Environmental flow components (EFCs) extracted from the reference...
Categories: Publication; Types: Citation; Tags: Ecohydrology
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The annual hydrograph of large rivers, including flood pulses and low-flow periods, is believed to play a primary role in the productivity of biota associated with these ecosystems. We investigated the relationship between river hydrology and Interior least tern (Sterna antillarum) reproductive success on the Lower Mississippi River from April to July 1986-1993. The number of fledglings produced per adult pair was negatively correlated with July mean (r= -0.95, p = 0.0004) and July maximum river elevation (r= -0.97, p = 0.0001), but no other aspect of river hydrology were related to tern reproduction. Low-water elevations in July may benefit least tern reproductive success by increasing sand island area or the area...
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A method to quantitatively characterize the bed forms of a large river and a preliminary test of the relationship between bed-form characteristics and catch per unit area of benthic fishes is presented. We used analog paper recordings of bathymetric data from the Missouri River and fish data collected from 1996 to 1998 at both the segment (???101-102-km) and macrohabitat (???10-1-100-km) spatial scales. Bed-form traces were transformed to digital data with image analysis software. The slope, mean residual, and SD of the residuals of the regression of depth versus distance along the bottom, as well as mean depth, were estimated for each trace. These four metrics were compared with sinuosity, fractal dimension, critical...
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Concern exists that polychlorinated biphenyls (PCBs) may be contributing to the current decline of shovelnose sturgeon (Scaphirhynchus platorynchus) and the US federally endangered pallid sturgeon (Scaphirhynchus albus). Waterborne exposures with newly fertilized eggs were used to assess developmental and morphological effects of 2 of the most potent aryl hydrocarbon receptor (AhR) agonists, 3,3′,4,4′,5-pentachlorobiphenyl (PCB-126) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), on early life stage shovelnose and pallid sturgeon. No dose-related effects of PCB-126 were observed on percent development or hatch in either species at concentrations as high as 1711 ng/g egg. Effects of TCDD on percent development were...
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The Lisbon Bottom Unit of the Big Muddy National Fish and Wildlife Refuge (Refuge) is approximately 2,200 acres and is the first complete unit of the Refuge. Primary objectives of the Refuge are to create and restore diverse riverine aquatic habitats and reconnect the Missouri River to its flood plain where feasible. Management seeks to accomplish these objectives by encouraging natural processes of erosion, deposition, and succession to the greatest extent possible.One of the most salient aquatic features of the Lisbon Bottom Unit is a newly created 2-mile-long free-flowing chute, or side channel (Fig. 1). This chute began forming as a levee breech scour hole during the Great Flood of 1993. The chute continued...
Categories: Publication; Types: Citation; Tags: Biological Science Report
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