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K.F. Tiffan

Publications and source records attributed to K.F. Tiffan.

At least 19 recordsLinked to original sources
USGS2011

Two alternative juvenile life history types for fall Chinook salmon in the Snake River basin

Fall Chinook salmon Oncorhynchus tshawytscha in the Snake River basin were listed under the Endangered Species Act in 1992. At the time of listing, it was assumed that fall Chinook salmon juveniles in the Snake River basin adhered strictly to an ocean-type life history characterized by saltwater entry at age 0 and first-year wintering in the ocean. Research showed, however, that some fall Chinook salmon juveniles in the Snake River basin spent their first winter in a reservoir and resumed seaward movement the following spring at age 1 (hereafter, reservoir-type juveniles). We collected wild and hatchery ocean-type fall Chinook salmon juveniles in 1997 and wild and hatchery reservoir-type juveniles in 1998 to assess the condition of the reservoir-type juveniles at the onset of seaward movement. The ocean-type juveniles averaged 112-139 mm fork length, and the reservoir-type juveniles averaged 222-224 mm fork length. The large size of the reservoir-type juveniles suggested a high potential for survival to salt water and subsequent return to freshwater. Scale pattern analyses of the fall Chinook salmon spawners we collected during 1998-2003 supported this point. Of the spawners sampled, an overall average of 41% of the wild fish and 51% of the hatchery fish had been reservoir-type juveniles. Males that had been reservoir-type juveniles often returned as small "minijacks" (wild, 16% of total; hatchery, 40% of total), but 84% of the wild males, 60% of the hatchery males, and 100% of the wild and hatchery females that had been reservoir-type juveniles returned at ages and fork lengths commonly observed in populations of Chinook salmon. We conclude that fall Chinook salmon in the Snake River basin exhibit two alternative juvenile life histories, namely ocean-type and reservoir-type. ?? Copyright by the American Fisheries Society 2005.

Idaho, Oregon, Washington↗
USGS2011

Diel spawning behavior of chum salmon in the Columbia River

We conducted a study during 2003 in a side channel of the Columbia River downstream of Bonneville Dam to describe the diel spawning behavior of wild chum salmon Oncorhynchus keta. We collected observational data on 14 pairs of chum salmon using a dual-frequency identification sonar. Spawners of both genders were observed chasing intruders during nighttime and daytime as nests were constructed. Regardless of diel period, females were engaged in digging to both construct nests and cover eggs, and courting males exhibited the prespawning behavior of tail-crossing. We observed a total of 13 spawning events, of which 9 occurred at night and 4 occurred during the day. Once chum salmon begin nest construction, visual cues are apparently not required for courtship, nest defense, and spawning. To enhance successful spawning, flows from Bonneville Dam during the spawning season were reduced during the day but were sometimes increased at night to pass water and meet power demand (i.e., reverse loading), the assumption being that chum salmon are inactive at night. Our findings show that this assumption was violated. Therefore, reverse loading may disrupt the complex prespawning behavior that occurs both during the day and at night, as well as attract spawners to areas that were dewatered during the day.

Transactions of the American Fisheries Society↗
USGS2009

Research in thermal biology: Burning questions for coldwater stream fishes

With the increasing appreciation of global warming impacts on ecological systems, in addition to the myriad of land management effects on water quality, the number of literature citations dealing with the effects of water temperature on freshwater fish has escalated in the past decade. Given the many biological scales at which water temperature effects have been studied, and the growing need to integrate knowledge from multiple disciplines of thermal biology to fully protect beneficial uses, we held that a survey of the most promising recent developments and an expression of some of the remaining unanswered questions with significant management implications would best be approached collectively by a diverse research community. We have identified five specific topic areas of renewed research where new techniques and critical thought could benefit coldwater stream fishes (particularly salmonids): molecular, organism, population/species, community and ecosystem, and policy issues in water quality. Our hope is that information gained through examination of recent research fronts linking knowledge at various scales will prove useful in managing water quality at a basin level to protect fish populations and whole ecosystems. Standards of the past were based largely on incipient lethal and optimum growth rate temperatures for fish species, while future standards should consider all integrated thermal impacts to the organism and ecosystem. ?? Taylor and Francis Group, LLC.

Reviews in Fisheries Science↗
USGS2004

Imaging fall Chinook salmon redds in the Columbia River with a dual-frequency identification sonar

We tested the efficacy of a dual-frequency identification sonar (DIDSON) for imaging and enumeration of fall Chinook salmon Oncorhynchus tshawytscha redds in a spawning area below Bonneville Dam on the Columbia River. The DIDSON uses sound to form near-video-quality images and has the advantages of imaging in zero-visibility water and possessing a greater detection range and field of view than underwater video cameras. We suspected that the large size and distinct morphology of a fall Chinook salmon redd would facilitate acoustic imaging if the DIDSON was towed near the river bottom so as to cast an acoustic shadow from the tailspill over the redd pocket. We tested this idea by observing 22 different redds with an underwater video camera, spatially referencing their locations, and then navigating to them while imaging them with the DIDSON. All 22 redds were successfully imaged with the DIDSON. We subsequently conducted redd searches along transects to compare the number of redds imaged by the DIDSON with the number observed using an underwater video camera. We counted 117 redds with the DIDSON and 81 redds with the underwater video camera. Only one of the redds observed with the underwater video camera was not also documented by the DIDSON. In spite of the DIDSON's high cost, it may serve as a useful tool for enumerating fall Chinook salmon redds in conditions that are not conducive to underwater videography.

North American Journal of Fisheries Management↗
USGS2004

Juvenile and adult fall Chinook and chum salmon habitat studies below Bonneville Dam on the Columbia River. Annual report 2002-2003

We investigated spatial and temporal changes in subyearling fall Chinook salmon rearing habitat and areas dewatered below Bonneville Dam on the Columbia River. We used two-dimensional hydrodynamic modeling to predict water velocity and depth data. By combining two-dimensional hydrodynamic modeling with a predictive model of subyearling rearing presence, we were able to illustrate spatiotemporal changes in subyearling rearing areas, areas dewatered by flow reductions, and percentage of dewatered locations that were initially subyearling rearing areas. By using a geographic information system, we located areas of persistent subyearling rearing and areas frequently dewatered at 1-h change intervals from 1 April through 31 May, 2003. We validated predicted water velocities and surface elevations using empirically collected water velocities and surface elevations. We beach seined to collect subyearlings at random locations within the study area to validate predictions of subyearling presence.

Oregon, Washington↗
USGS2003

Thermal exposure of juvenile fall chinook salmon migrating through a lower Snake River Reservoir

Impoundment of the Snake River, Washington, has resulted in high water temperatures and late seaward migration of juvenile fall chinook salmon during summer months. To determine if juvenile fall chinook salmon are exposed to temperatures higher than the upper incipient lethal, we tagged groups of fish with temperature-sensing radio tags and tracked them in Little Goose Reservoir on the Snake River during the summers of 1998 and 1999. Spatial and temporal patterns of the reservoir's thermal environment were described using a bathythermograph. Little Goose Reservoir was generally homothermic, and temperatures selected by fish were typically not significantly different from mean water temperatures. No areas of thermal refugia existed in Little Goose Reservoir. Thermal exposure was most influenced by fish residence time in the reservoir within each year and by temperature differences between years. Current augmentation of Snake River summer flows with cold-water releases from Dworshak Dam in Idaho reduces the thermal exposure of juvenile fall chinook salmon by lowering water temperatures up to 4??C and may therefore increase their survival. Continued flow augmentation using water from Dworshak Reservoir may be the only mechanism to meet the temperature standard for the lower Snake River.

Idaho, Oregon, Washington↗
USGS2002

Quantifying flow-dependent changes in subyearling fall chinook salmon rearing habitat using two-dimensional spatially explicit modeling

We used an analysis based on a geographic information system (GIS) to determine the amount of rearing habitat and stranding area for subyearling fall chinook salmon Oncorhynchus tshawytscha in the Hanford Reach of the Columbia River at steady-state flows ranging from 1,416 to 11,328 m3/s. High-resolution river channel bathymetry was used in conjunction with a two-dimensional hydrodynamic model to estimate water velocities, depths, and lateral slopes throughout our 33-km study area. To relate the probability of fish presence in nearshore habitats to measures of physical habitat, we developed a logistic regression model from point electrofishing data. We only considered variables that were compatible with a GIS and therefore excluded other variables known to be important to juvenile salmonids. Water velocity and lateral slope were the only two variables included in our final model. The amount of available rearing habitat generally decreased as flow increased, with the greatest decreases occurring between 1,416 and 4,814 m3/s. When river discharges were between 3,682 and 7,080 m3/s, flow fluctuations of 566 m3/s produced the smallest change in available rearing area (from -6.3% to +6.8% of the total). Stranding pool area was greatly reduced at steady-state flows exceeding 4,531 m3/s, but the highest net gain in stranding area was produced by 850 m3/s decreases in flow when river discharges were between 5,381 and 5,664 m3/s. Current measures to protect rearing fall chinook salmon include limiting flow fluctuations at Priest Rapids Dam to 850 m3/s when the dam is spilling water and when the weekly flows average less than 4,814 m3/s. We believe that limiting flow fluctuations at all discharges would further protect subyearling fall chinook salmon.

Washington↗
USGS2002

Comparison of subyearling fall chinook salmon's use of riprap revetments and unaltered habitats in Lake Wallula of the Columbia river

Subyearling fall chinook salmon's Oncorhynchus tshawytscha use of unaltered and riprap habitats in Lake Wallula of the Columbia River was determined with point abundance data collected by electrofishing in May 1994 and 1995. We documented the presence or absence of subyearlings at 277 sample sites and collected physical habitat information at each site. Based on logistic regression, we found that the probability of fish presence was greater in unaltered shoreline habitats than in riprap habitats. Substrate size was the most important factor in determining fish presence, with dominant substrates larger than 256 mm having the lowest probability of fish presence. Water velocity, also included in our model due to its biological importance, was not a significant factor affecting presence or absence (P = 0.1102). The correct prediction rate of fish presence or absence in our sample sites using cross validation was 67%. Our model showed that substrate was the most important factor determining subyearling habitat use, but the model did not include other habitat variables known to be important to subyearlings in more diverse systems. We suggest that resource managers consider alternative methods of bank stabilization that are compatible with the habitat requirements of the fish that use them.

Washington↗
USGS2000

Identification of juvenile fall versus spring chinook salmon migrating through the lower Snake River based on body morphology

We tested the use of body morphology to distinguish among subyearling fall-run, subyearling spring-run, and yearling spring-run smolts of chinook salmon Oncorhynchus tshawytscha at two lower Snake River dams during the summer emigration. Based on principal-components analysis, subyearling fall-run chinook salmon had smaller heads and eyes, deeper bodies, and shorter caudal peduncles than yearling spring-run chinook salmon. Subyearling spring-run chinook salmon had characteristics of both subyearling fall-run and yearling spring-run chinook salmon. Subyearling fall-run and yearling spring-run chinook salmon were classified with more than 80% accuracy by means of discriminant analysis. Classification accuracy for subyearling spring-run chinook salmon was only 26%. We conclude that body morphology can be used to accurately identify the age of chinook salmon smolts but not the run. Therefore, genetic analyses are the only means of reliably determining the run composition of summer migrants in the lower Snake River.

Transactions of the American Fisheries Society↗
USGS2000

Physiological development and migratory behavior of subyearling fall chinook salmon in the Columbia River

We describe the migratory behavior and physiological development of subyearling fall chinook salmon Oncorhynchus tshawytscha migrating through John Day Reservoir on the Columbia River, Washington and Oregon. Fish were freeze-branded and coded-wire-tagged at McNary Dam, Oregon, from 1991 to 1994, to determine travel time to John Day Dam and subsequent adult contribution. Stepwise multiple regression showed that 47% of the variation in subyearling fall chinook salmon travel time was explained by the reciprocal of minimum flow and fish size. Smoltification, as measured by gill Na+-K+ adenosine triphosphatase (ATPase) activity, was not important in explaining variability in travel time of subyearling chinook salmon. Fish marked early in the out-migration generally traveled faster than middle and late migrants. Seawater challenges were used to describe physiological development and showed that osmoregulatory competence of premigrants in the Hanford Reach of the Columbia River increased with fish size and gill ATPase activity. Once active migrants began passing McNary Dam, fish generally had survival exceeding 90% and were able to regulate their blood plasma Na+ in seawater. Gill ATPase activity increased as premigrants, reared in nearshore areas of the Hanford Reach, reached a peak among active migrants in late June and early July then decreased through the remainder of the out-migration. Salinity preference also peaked in subyearling fall chinook salmon during late June to mid July in 1995. Return of adults from marked groups showed no consistent patterns that would suggest a survival advantage for any portion of the juvenile out-migration. Presumed wild migrants from the middle and late portions of the out-migration were primary contributors to all fisheries, except the Priest Rapids Hatchery. As such, fishery managers should take action to ensure the survival of these fish, especially because they migrate under more unfavorable environmental conditions than early migrants.

Oregon; Washington↗
USGS1996

Performance of antimycin in high-gradient streams

A variety of low- to high-gradient streams in Colorado and Montana were treated with the fish toxicant antimycin (Fintrol) to evaluate its efficacy in relation to stream gradient. In general, a dose of 8 μg/L delivered for 8 h effectively killed brook trout Salvelinus fontinalis and rainbow trout Oncorhynchus mykiss over an elevation drop of 60–75 m where pH was low (≤7.0) and water temperature was warm (≥10°C). Colder water temperatures and higher pHs reduced the effectiveness of antimycin.

Colorado, Montana↗