Comparison of Spawning Areas and Times for Two Runs of Chinook Salmon (Oncorhynchus tshawytscha) in the Kenai River, Alaska

1985 ◽  
Vol 42 (4) ◽  
pp. 693-700 ◽  
Author(s):  
Carl V. Burger ◽  
Richard L. Wilmot ◽  
David B. Wangaard

From 1979 to 1982,188 chinook salmon (Oncorhynchus tshawytscha) were tagged with radio transmitters to locate spawning areas in the glacial Kenai River, southcentral Alaska. Results confirmed that an early run entered the river in May and June and spawned in tributaries, and a late run entered the river from late June through August and spawned in the main stem. Spawning peaked during August in tributaries influenced by lakes, but during July in other tributaries. Lakes may have increased fall and winter temperatures of downstream waters, enabling successful reproduction for later spawning fish within these tributaries. This hypothesis assumes that hatching and emergence can be completed in a shorter time in lake-influenced waters. The time of upstream migration and spawning (mid- to late August) of the late run is unique among chinook stocks in Cook Inlet. This behavior may have developed only because two large lakes (Kenai and Skilak) directly influence the main-stem Kenai River. If run timing is genetically controlled, and if the various components of the two runs are isolated stocks that have adapted to predictable stream temperatures, there are implications for stock transplantation programs and for any activities of man that alter stream temperatures.

1997 ◽  
Vol 54 (7) ◽  
pp. 1585-1592 ◽  
Author(s):  
M J Bradford ◽  
G C Taylor

Immediately after emergence from spawning gravels, fry of stream-type chinook salmon (Oncorhynchus tshawytscha) populations from tributaries of the upper Fraser River, British Columbia, distribute themselves downstream from the spawning areas, throughout the natal stream, and into the Fraser River. We tested the hypothesis that this range in dispersal distances is caused by innate differences in nocturnal migratory tendency among individuals. Using an experimental stream channel, we found repeatable differences in downstream movement behaviour among newly emerged chinook fry. Fish that moved downstream were larger than those that held position in the channel. However, the incidence of downstream movement behaviours decreased over the first 2 weeks after emergence. We propose that the variation among individuals in downstream movement behaviour we observed leads to the dispersal of newly emerged fry throughout all available rearing habitats. Thus, between- and within-population variation in the freshwater life history observed in these populations may be caused by small differences in the behaviour of individuals.


2018 ◽  
Vol 69 (12) ◽  
pp. 1995 ◽  
Author(s):  
George P. Naughton ◽  
Matthew L. Keefer ◽  
Tami S. Clabough ◽  
Matthew J. Knoff ◽  
Timothy J. Blubaugh ◽  
...  

Trap-and-haul is a mitigation strategy at many hydropower dams lacking upstream fish-passage facilities, and protocols are needed to maximise its effectiveness. We used biotelemetry to assess the potential benefits of releasing transported adult Chinook salmon (Oncorhynchus tshawytscha) into a cold-water reservoir v. a relatively warm-water tributary before spawning. Over 5 years, we released 160 salmon into Foster Reservoir (Oregon, USA) and another 102 into the South Santiam River near historical salmon spawning areas further upstream. In total, 70% of reservoir-released salmon entered an upriver tributary after spending a median of 3–95 days annually in the reservoir. Data recovered from 61 archival temperature loggers indicated that salmon were ~3–6°C cooler per day in the reservoir than in the river. We estimated that cumulative exposure of reservoir-released fish was reduced by 64 degree days, on average (range=–129 to 392), relative to river-released fish. Release into the reservoir was not risk free; 14% of all reservoir-released fish fell back downstream v. 1% of river-released fish. We conclude that reduced transport distance, reduced thermal exposure and potential survival benefits of releasing salmon into reservoirs should be weighed against risks of factors such as fallback and homing errors.


2005 ◽  
Vol 119 (4) ◽  
pp. 591 ◽  
Author(s):  
Jeffrey S. Gleason ◽  
Ryan A. Hoffman ◽  
James M. Wendland

We report observations of Beavers (Castor canadensis) foraging and feeding on discarded Chinook Salmon (Oncorhynchus tshawytscha) carcasses within the confines of the Susitna River drainage in southcentral Alaska on three separate occasions between 1999 and 2004. In all three instances, Beavers were observed actively seeking out freshly discarded carcasses or transporting “fresh” salmon carcasses in their mouths. In one instance, Beavers were seen using their dextrous forefeet to “handle” chunks of salmon while hunched over carcasses and in this case we actually witnessed Beavers “chewing” and ingestion was assumed. In the other two instances, Beavers were observed swimming with salmon carcasses in their mouths. Though unique within the framework of Beaver foraging ecology, we suggest this behavior may be a fairly common strategy employed by Beavers in Alaskan streams and rivers to take advantage of a seasonally superabundant source of protein.


1992 ◽  
Vol 49 (12) ◽  
pp. 2621-2629 ◽  
Author(s):  
S. W. Johnson ◽  
J. F. Thedinga ◽  
K. V. Koski

Distribution, abundance, habitat preference, migration and residence timing, seawater tolerance, and size were determined for juvenile ocean-type (age 0) chinook salmon (Oncorhynchus tshawytscha) in the Situk River, Alaska. Chinook primarily occupied main-stem habitats (channel edges in spring, pools and willow edges in summer). Peak chinook densities in the upper and lower main stem were 96 and 76 fish/100 m2, respectively. Chinook migrated downstream in two phases: a spring dispersal of emergent fry and a summer migration. Chinook marked in the upper river in late June and early July were recaptured 20 km downstream in the lower river in late July. Marked chinook resided in the lower river up to 34 d. Mean fork length of chinook in the lower river increased from 40 mm in May to 80 mm in early August. By late August, chinook had emigrated from the lower river at a size of approximately 80 mm. Fish this size were seawater tolerant and had the physical appearance of smolts. Ocean-type chinook in the Situk River are unique because in most Alaskan streams, chinook are stream-type (rear in freshwater at least 1 yr).


2017 ◽  
Vol 8 (2) ◽  
pp. 558-586 ◽  
Author(s):  
Randy J. Brown ◽  
Al von Finster ◽  
Robert J. Henszey ◽  
John H. Eiler

Abstract Chinook Salmon Oncorhynchus tshawytscha return to the Yukon River in northwestern North America each summer, migrating to spawning destinations from the lower river to more than 3,000 km upstream. These returns support numerous fisheries throughout the basin. Despite a long history of fisheries research and management, there is no comprehensive account of Chinook Salmon spawning areas in the basin. To address this issue, we cataloged, summarized, and mapped the known spawning areas of Yukon River Chinook Salmon by using a variety of sources including published articles, gray literature, and information archived in agency databases. Most of our sources were published within the past 30 y, but some refer to observations that were recorded as long ago as the late 1800s. We classified spawning areas as major or minor producers with three indicators of abundance: 1) quantitative estimates of escapement (major producer if ≥500 fish, minor producer if <500 fish), 2) radiotelemetry-based proportions of annual production (major producer if ≥1% of the run, minor producer if <1% of the run), and 3) aerial survey index counts (major producer if ≥165 fish observed, minor producer if <165 fish observed). We documented 183 spawning areas in the Yukon River basin, 79 in the United States, and 104 in Canada. Most spawning areas were in tributary streams, but some were in main-stem reaches as well. We classified 32 spawning areas as major producers and 151 as minor producers. The Chinook Salmon spawning areas cataloged here provide a baseline that makes it possible to strategically direct abundance, biological sampling, and genetics projects for maximum effect and to assess both spatial and temporal changes within the basin.


2000 ◽  
Vol 57 (8) ◽  
pp. 1647-1656 ◽  
Author(s):  
David R Geist

Fall chinook salmon (Oncorhynchus tshawytscha) spawned predominantly in areas of the Hanford Reach of the Columbia River where hyporheic water discharged into the river channel. This upwelling water had a dissolved solids content (i.e., specific conductance) indicative of river water and was presumed to have entered highly permeable riverbed substrate at locations upstream of the spawning areas. Hyporheic discharge zones composed of undiluted ground water or areas with little or no upwelling were not used by spawning salmon. Rates of upwelling into spawning areas averaged 1200 L·m-2·day-1 (95% CI = 784-1665 L·m-2·day-1) as compared with approximately 500 L·m-2·day-1 (95% CI = 303-1159 L·m-2·day-1) in nonspawning areas. Dissolved oxygen content of the hyporheic discharge near salmon spawning areas was about 9 mg·L-1 (±0.4 mg·L-1) whereas in nonspawning areas, dissolved oxygen values were 7 mg·L-1 (±0.9 mg·L-1) or lower. In both cases, dissolved oxygen of the river water was higher (11.3 ± 0.3 mg·L-1). Physical and chemical gradients between the hyporheic zone and the river may provide cues for adult salmon to locate suitable spawning areas. This information will help fisheries managers to describe the suitability of salmon spawning habitat in large rivers.


2009 ◽  
Vol 66 (10) ◽  
pp. 1658-1665 ◽  
Author(s):  
Timothy Copeland ◽  
David A. Venditti

The most productive juvenile life history in the Pahsimeroi River Chinook salmon ( Oncorhynchus tshawytscha ; Idaho, USA) population (in terms of smolt production) is being eliminated. Length at emigration and survival from spawning areas to Lower Granite Dam within each of three juvenile phenotypes (age-0 smolts, fall parr, age-1 smolts) were influenced by initial cohort abundance. The proportion of age-1 emigrants reaching Lower Granite Dam was dome-shaped with respect to initial cohort abundance. As initial abundance increased, higher proportions of juveniles adopted the age-1 smolt phenotype or emigrated as fall parr. The age-0 smolt phenotype had the highest relative survival, and the fall parr phenotype, the lowest. The contributions of each emigrant type to cohort smolt production varied with circumstances; hence, the full expression of phenotypic diversity is important to the study population. However, there were no records of tagged age-0 smolts surviving to return from the Pacific Ocean. Given the potential productivity of this life history, management and recovery efforts should be directed at the age-0 smolt phenotype.


2013 ◽  
Vol 70 (5) ◽  
pp. 735-746 ◽  
Author(s):  
Peter A.H. Westley ◽  
Thomas P. Quinn ◽  
Andrew H. Dittman

Here we ask whether straying differs among species, life history types, and populations of adult hatchery-produced Pacific salmon (Oncorhynchus spp.) and steelhead (Oncorhynchus mykiss) in the Columbia River basin. Previous estimates of straying have been confounded by various factors influencing the probability of individuals returning to non-natal sites (e.g., off-station releases), whereas analyses undertaken here of nearly a quarter million coded-wire tag recoveries control for these factors. Our results revealed large and generally consistent differences in the propensity to stray among species, life history types within species, and populations. Paired releases indicated that (i) Chinook salmon (Oncorhynchus tshawytscha) strayed more (mean population range 0.11%–34.6%) than coho salmon (Oncorhynchus kisutch) (0.08%–0.94%); (ii) ocean-type Chinook (5.2%–18.6%) strayed more than stream-type Chinook (0.11%–10%); and Chinook salmon (0.90%–54.9%) strayed more than steelhead (0.30%–2.3%). We conclude these patterns are largely the result of species-specific behavioral and endocrine factors during the juvenile life stages, but analyses also suggest that environmental factors can influence straying during the adult upstream migration.


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