Sauger Sander canadensis populations throughout North America have exhibited declines over the past few decades. Various factors may be contribute to the reduced population abundance of saugers in the middle Missouri River of Montana, including interspecific competition with walleyes Sander vitreus. We compared the seasonal migrations, habitat use, and diets of both species in the middle Missouri River to assess competition potential. Before the presumed spawning period, 96% of saugers and 57% of walleyes migrated as far as 264 kilometers downstream. After spawning, both species returned to previously occupied river reaches and demonstrated site fidelity during the nonmigratory season. Habitat use by saugers and walleyes was similar at three hierarchical spatial scales. Diet overlap was high during the spring and summer and moderate during autumn. Resource overlap of saugers and walleyes in the middle Missouri River of Montana suggests that the competition potential between these species is high, which may preclude the recovery of native sauger populations where resources are limiting.

Pallid sturgeon, Scaphirhynchus albus, have declined throughout the Missouri River since dam construction and inception of the Bank Stabilization and Navigation Project in 1912. Their decline likely is due to the loss and degradation of their natural habitat as a result of changes in the river's structure and function, as well as the pallid sturgeon's inability to adapt to these changes. The U. S. Army Corps of Engineers has been working with state and federal agencies to develop and conduct a Pallid Sturgeon Population Assessment Project (PAP), with the goal of recovering pallid sturgeon populations. The PAP has organized the monitoring and assessment efforts into distinct geographic segments, with state and federal resource management agencies possessing primary responsibility for one or more segment. To date, the results from annual monitoring have been reported for individual Program segments. However, monitoring results have not been summarized or evaluated for larger spatial scales, encompassing more than one PAP segment. This report describes a summary conducted by the Pacific Northwest National Laboratory (PNNL) that synthesizes the 2005 sampling year monitoring results from individual segments. The study area encompasses the Missouri River from Fort Peck Dam, Montana at river mile (RM) 1771.5 downstream to the confluence of the Missouri and Mississippi Rivers near St. Louis, Missouri (RM 0) and the lower reach of the Kansas River. The Pallid Sturgeon Population Assessment Team has designated 14 sampling segments on the Missouri River mainstem and the lower Kansas River encompassing high priority management areas for pallid sturgeon. Segments 1-4, encompass the area from Fort Peck Dam to the headwaters of Lake Sakakawea, comprising the upper basin monitoring area. Segments 5-14, encompass the region from Fort Randall Dam to the mouth of the Missouri River and comprise the lower basin monitoring area. In 2005, segment 4 was the only segment in the upper basin to be sampled, so these data are not presented in this report as they are available in the 2005 Annual Report for Segment 4. This report represents a compilation and evaluation of data for segments 5 through 14 (lower basin) for the 2005 sampling year. i Sampling and data collection were conducted by the Pallid Sturgeon Population Assessment Teams in accordance with standard operating procedures established by a panel of representatives from various state and federal agencies involved with pallid recovery on the Missouri River (Drobish 2006a) and compiled in the Missouri Department of Conservation (MDC) database. Records from the MDC database were transferred to PNNL for data evaluation and summarization. For the 2005 sampling year in the lower basin of the Missouri River, four gear types were used to sample a range of 55 to 93 bends during the sturgeon and fish community seasons. The inside bends and channel crossovers were the most frequently sampled macrohabitats during both seasons, where approximately 57% and 23%, respectively, of the sampling ef...

The U.S. Army Corps of Engineers (USACE) Portland District places a high priority on increasing the understanding of the migratory behavior and survival of juvenile salmonids emigrating through the lower 235 km of the Columbia River and estuary. This understanding is critical to determining the effects of the Federal Columbia River Power System (FCRPS) on the 'post-hydrosystem' performance of these populations. Increased survival rates through the FCRPS and through the estuary are necessary to meet recovery goals set forth in the 2008 Biological Opinion (BiOp) on FCRPS operations. The goal of the study reported herein is to provide information regarding the migratory behavior and survival data from juvenile salmonids passing through the lower Columbia River and estuary between Bonneville Dam and the Pacific Ocean. The study was conducted by the Pacific Northwest National Laboratory using the Juvenile Salmon Acoustic Telemetry System (JSATS). The Portland District of the USACE and regional fisheries managers will use the information to manage the configuration and operation of the FCRPS and to evaluate management actions such as estuary habitat restoration and avian predation management to maximize survival rates of juvenile salmonids. ObjectivesIn this report we present estimated survival of acoustic-tagged juvenile yearling Chinook salmon (CH1), steelhead (STH), and subyearling Chinook salmon (CH0) downstream of Bonneville Dam as they migrated seaward through the Columbia River and its estuary. This study also provides, for the first time, estimates of survival through the lower 192 km of the Columbia River and estuary for groups of fish with known passage routes at John Day and Bonneville dams. The primary objective of this study was to estimate the survival of yearling and subyearling Chinook salmon and steelhead through multiple reaches of the Columbia River between Bonneville Dam and the Pacific Ocean. Other objectives were to, 1) compare the effects of FCPRS passage history on mortality of juvenile salmonids in the lower 192 km of the Columbia River and estuary, and 2) monitor and map migration pathway and habitat associations and behaviors relative to these pathways to support habitat restoration activities. MethodsThis study took advantage of JSATS-tagged fish collected and tagged at John Day Dam and released into the reservoir 41 km upstream of John Day Dam (near Roosevelt, WA at river kilometer (rkm) 388) during the spring and summer of 2009 for another Portland District project; "Studies of Surface Spill at John Day Dam" study (SPE-P-08-03). All study fish were double tagged with a 0.43 g JSATS acoustic transmitter and a passive integrated transponder (PIT) tag. The study area included the Columbia River and estuary between Bonneville Dam (rkm 235) and the mouth of the Columbia River (rkm 2.8). Autonomous acoustic receivers were deployed at 104 locations between the forebay of Bonneville Dam (rkm 236) and rkm 2.8 between 27 April and 17 August 2009. Receivers were recovered, tested, and redeployed eve...

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