Geoffrey A. McMichael

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...

Physicochemical Characteristics of the Hyporheic Zone Affect Redd Site Selection by Chum Salmon and Fall Chinook Salmon in the Columbia River

Abstract Chum salmon Oncorhynchus keta and fall chinook salmon O. tshawytscha spawned at separate locations in a side channel near Ives Island, Washington, in the Columbia River downstream of Bonneville Dam. We hypothesized that measurements of water depth, substrate size, and water velocity would not sufficiently explain the separation in spawning areas and began a 2-year investigation of physicochemical characteristics of the hyporheic zone. We found that chum salmon spawned in upwelling water that was significantly warmer than the surrounding river water. In contrast, fall chinook salmon constructed redds at downwelling sites, where there was no difference in temperature between the river and its bed. An understanding of the specific factors affecting chum salmon and fall chinook salmon redd site selection at Ives Island will be useful to resource managers attempting to maximize available salmonid spawning habitat within the constraints imposed by other water resource needs.

Effects of Residual Hatchery-Reared Steelhead on Growth of Wild Rainbow Trout and Spring Chinook Salmon

Abstract We investigated the effects of nonmigrant (residual) juvenile hatchery steelhead (anadromous rainbow trout Oncorhynchus mykiss) on growth of wild rainbow trout and juvenile spring Chinook salmon O. tshawytscha to examine how increased densities of residual hatchery steelhead might affect the growth of preexisting wild rainbow trout and Chinook salmon. We used screened enclosures in a natural stream to examine food utilization and physiological stress, factors that might affect fish growth. The presence of residual hatchery steelhead led to reduced growth of wild rainbow trout (1993: P = 0.019; 1994: P = 0.020) but not of spring Chinook salmon (P = 0.360). Enclosures did not reduce the total number of food items available but did influence the species composition of aquatic and terrestrial invertebrates. The food habits of paired and unpaired fish differed; however, the power of those tests was low. Cortisol level, a measure of physiological stress, did not differ between paired and unpaired fish ...

Behavioral Interactions among Hatchery-Reared Steelhead Smoltsand Wild Oncorhynchus mykiss in Natural Streams

Abstract The potential for hatchery fish to negatively impact wild fish has been identified as a concern for dwindling stocks of naturally produced anadromous salmonids in the Pacific Northwest. Using a control–treatment approach, we performed a multiscale examination of potential behavioral impacts of releases of hatchery-produced steelhead Oncorhynchus mykiss (anadromous rainbow trout) on preexisting wild populations of O. mykiss (anadromous and potamodromous) over a 4-year period. We released approximately 33,000 conventionally reared hatchery steelhead smolts (treatment) into an upper Yakima River tributary in 1991, 1992, 1993, and 1994 and investigated behavioral interactions and small-scale displacement (0.2–5.0 m). Snorkelers conducted behavioral observations and observed small-scale displacements in treatment and control streams for approximately 1 month following releases. Hatchery steelhead were generally larger than wild O. mykiss and dominated most (68%) contests. The types of behavioral inter...

Examination of Electrofishing Injury and Short-Term Mortality in Hatchery Rainbow Trout

Abstract Four groups of hatchery-reared rainbow trout Oncorhynchus mykiss were exposed to different direct current voltages and pulse rates from a battery-powered backpack electrofisher. A control group was not exposed to electrofishing. The four experimental groups of 30–35 fish each and the control group of approximately 100 fish were monitored daily for 7 d following the initial electrofishing treatments to determine the extent of delayed short-term mortality. Samples were collected after 7 d with the same electrofisher settings as were initially used (a sample was seined from the control group) and were necropsied within 2 h of collection. Fish from each treatment group and the control group were examined for spinal injury by filleting the fish on both sides and visually determining the presence or absence of spinal column damage and associated hemorrhaging in surrounding musculature. In total, 114 fish (17–29 from each group) were necropsied. Fish from the control group showed no signs of injury. Inj...

Electrofishing Injury to Stream Salmonids; Injury Assessment at the Sample, Reach, and Stream Scales

Abstract Electrofishing injury rates in rainbow trout and juvenile steelhead Oncorhynchus mykiss and juvenile spring chinook salmon O. tshawytscha were quantified in samples collected in four tributaries to, and one reach of, the Yakima River, Washington. Estimated electrofishing injury rates at the reach and stream scales were generated by using sample injury rates, derived from this study, multiplied by capture probabilities and the fraction of habitat sampled. Sample injury rates in small O. mykiss and juvenile spring chinook salmon were low. Mean electrofishing injury rate in O. mykiss samples captured in tributaries was 5.1%. Only 2.0% of the juvenile spring chinook salmon captured by electrofishing in the Yakima River were injured. Larger O. mykiss (≥250 mm fork length, FL) were injured at a significantly higher rate (27.7%) than their smaller counterparts (1.2%; P = 0.023) in the Yakima River sample. Electrofishing injury rates decreased with increasing scale from the sample to the reach and stream...

Estimated Fall Chinook Salmon Survival to Emergence in Dewatered Redds in a Shallow Side Channel of the Columbia River

Abstract Fall Chinook salmon Oncorhynchus tshawytscha often spawn in the tailraces of large hydroelectric dams on the Columbia River. Redds built in shallow habitats downstream of these dams may be periodically dewatered as a result of load-following operations and subsequent changes in water surface elevation before the fry emerge. To determine whether fall Chinook salmon redds in a shallow area subjected to periodic dewatering downstream of Wanapum Dam on the Columbia River produced live fry, we installed seven redd caps and monitored emergence. Large numbers of live fry were captured from the redds between March 9 and May 18, 2003. Estimated survival from egg to fry for these redds, which were dewatered approximately 3.1% of the time during the posthatch intragravel rearing period, ranged from 16.9% to 66.6% and averaged 29.2% (assuming 4,272 viable eggs/redd). The peak emergence date ranged from April 1 to April 29 (average, about April 14). Peak emergence dates corresponded well with predicted emerge...

Comparing Fish Screen Performance to Physical Design Criteria

Abstract Fish screens associated with irrigation diversion structures perform a vital function by protecting rearing and migrating fishes. Irrigation diversions in the western United States were developed in the late 1800s and early 1900s with little regard to how they might affect fish populations. Fish screens were installed on some diversions beginning in the 1930s but were often ineffective. Beginning in the 1980s a “modern-era” fish screening program was initiated in the Yakima River basin in Washington State. A systematic phased approach was employed, with federal funding, to replace antiquated screens and to install screens where there had not previously been fish protection devices. Also during this time, the federal and state agencies responsible for protecting the fish resources developed regional criteria to guide design of these facilities. These criteria, developed by the National Marine Fisheries Service and used by the Washington Department of Fish and Wildlife, dictated physical metrics su...

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 ...

Upstream Movement of Residual Hatchery Steelhead into Areas Containing Bull Trout and Cutthroat Trout

Abstract Hatchery-reared steelhead Oncorhynchus mykiss that do not emigrate as smolts shortly after release may harm wild fish communities through ecological interactions. We used systematic, stratified snorkeling surveys to document the relative abundance of wild rainbow trout (nonanadromous O. mykiss), bull trout Salvelinus confluentus, and westslope cutthroat trout O. clarki lewisi as well as the upstream limit of residual hatchery steelhead (hatchery-reared steelhead that had failed to emigrate by June 1). Our objective was to determine whether residual hatchery steelhead had migrated upstream from their release point into an area containing westslope cutthroat trout and a threatened population of bull trout. Hatchery steelhead made up a larger proportion of the salmonid community in the sites near their release location and constituted a lower proportion as distance upstream from the release location increased. However, residual hatchery steelhead had migrated over 12 km upstream into an area contain...