Blaine D. Ebberts

The Juvenile Salmon Acoustic Telemetry System: A New Tool

Abstract Limitations of biotelemetry technology available in 2001 prompted the U.S. Army Corps of Engineers Portland District to develop a new acoustic telemetry system to monitor survival of juvenile salmonids through the Columbia River to the Pacific Ocean. Eight years later, the Juvenile Salmon Acoustic Telemetry System (JSATS) consists of microacoustic transmitters (12 mm long, 0.43 g weight in air), autonomous and cabled receiving systems, and data management and processing applications. Transmitter pulse rate can be user-defined and as configured for this case study was set at 5 seconds, with an estimated tag life of 30 days and detection range of 300 m. Before JSATS development, no technology existed to study movement and survival of fish smaller than 10 g migrating long distances from freshwater and into saltwater. In a 2008 study comparing detection probabilities, travel times, and survival of 4,140 JSATS-tagged and 48,433 passive integrated transponder (PIT)-tagged yearling Chinook salmon (Oncor...

Assessment of Barotrauma from Rapid Decompression of Depth-Acclimated Juvenile Chinook Salmon Bearing Radiotelemetry Transmitters

Abstract This study investigated the mortality of and injury to juvenile Chinook salmon Oncorhynchus tshawytscha exposed to simulated pressure changes associated with passage through a large Kaplan hydropower turbine. Mortality and injury varied depending on whether a fish was carrying a transmitter, the method of transmitter implantation, the depth of acclimation, and the size of the fish. Juvenile Chinook salmon implanted with radio transmitters were more likely than those without to die or sustain injuries during simulated turbine passage. Gastric transmitter implantation resulted in higher rates of injury and mortality than surgical implantation. Mortality and injury increased with increasing pressure of acclimation. Injuries were more common in subyearling fish than in yearling fish. Gas emboli in the gills and internal hemorrhaging were the major causes of mortality. Rupture of the swim bladder and emphysema in the fins were also common. This research makes clear that the exposure of juvenile Chinoo...

Effect of Migration Pathway on Travel Time and Survival of Acoustic-Tagged Juvenile Salmonids in the Columbia River Estuary

Abstract We applied acoustic telemetry methods to characterize migration pathways and estimate associated travel times and survival probabilities for juvenile Chinook salmon Oncorhynchus tshawytscha and steelhead O. mykiss migrating downstream through the Columbia River estuary (from river kilometer [rkm] 86 to rkm 8). Acoustic-tagged fish were detected as migrating in the navigation channel and in off-channel areas at each of the estuarine reaches we examined during May–August 2010. However, the majority of fish traveled in the main navigation channel from rkm 86 to rkm 37, at which point most fish left the river-influenced navigation channel; crossed a broad, shallow tidal flat; and migrated the final 37 km in a secondary channel, which was characterized as having greater tidal transport than the navigation channel. The pathway used by acoustic-tagged smolts to migrate through the estuary affected their rate of travel. In most reaches, navigation channel migrants traveled significantly faster than fish ...

Effects of Jet Entry at High Flow Outfalls on Juvenile Pacific Salmon

Abstract We conducted field studies and laboratory experiments to explore the relationship between direct injury and mortality rates of juvenile Pacific salmon Oncorhyncus spp. and the jet entry velocities characteristic of high-flow (>28.3 m3/s) outfalls at hydroelectric facilities. During field tests, the range of calculated mean entry velocities was 9.3–13.7 m/s for low (28.3 m3/s) and high (68.0–70.2 m3/s) outfall discharge rates and two receiving water elevations. Mortality and injury rates of balloon-tagged hatchery juvenile spring chinook salmon O. tshawytscha in the field tests were less than 1%. At a high-velocity flume in a laboratory, small (87–100 mm fork length (FL)) and large (135–150 mm FL) hatchery fall chinook salmon were exposed to velocities of 0.0–24.4 m/s in a fast-fish-to-slow-water scenario. Jet entry velocities up to 15.2 m/s provided benign passage conditions for the sizes and physiological states of juvenile salmonids tested under the particular environmental conditions present d...

A Levels-of-Evidence Approach for Assessing Cumulative Ecosystem Response to Estuary and River Restoration Programs

Large-scale ecological restoration programs are beginning to supplement isolated projects implemented on rivers and tidal waterways. Nevertheless, the effects of estuary and river restoration often continue to be evaluated at local project scales or by integration in an additive manner. Today, we have sufficient scientific understanding to apply knowledge gained from measuring cumulative impacts of anthropogenic stressors on ecosystems to assessment of ecological restoration. Integration of this knowledge has potential to increase the efficacy of restoration projects that are conducted at several locations but comanaged within the confines of a larger integrative program. We introduce a framework based on a levels-of-evidence approach that facilitates assessment of the cumulative landscape effects of individual restoration actions taken at many different locations. It incorporates data collection at restoration and reference sites, hydrodynamic modeling, geographic information systems, and meta-analyses in a five-stage process: design, data development, analysis, synthesis and evaluation, and application. This framework evolved from the need to evaluate the efficacy of restoration projects that are being implemented in numerous wetlands on the 235 km tidal portion of the Columbia River, USA, which are intended to increase rearing habitat for out-migrating juvenile salmonid fishes.

Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2006

The goal of this multi-year study (2004-2010) is to develop a methodology to evaluate the cumulative effects of multiple habitat restoration projects intended to benefit ecosystems supporting juvenile salmonids in the lower Columbia River and estuary. Literature review in 2004 revealed no existing methods for such an evaluation and suggested that cumulative effects could be additive or synergistic. Field research in 2005, 2006, and 2007 involved intensive, comparative studies paired by habitat type (tidal swamp vs. marsh), trajectory (restoration vs. reference site), and restoration action (tide gate vs. culvert vs. dike breach). The field work established two kinds of monitoring indicators for eventual cumulative effects analysis: core and higher-order indicators. Management implications of limitations and applications of site-specific effectiveness monitoring and cumulative effects analysis were identified.

Evaluation of Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2010

Draft annual report for the Cumulative Effects Study for the US Army Corps of Engineers, Portland District