Impact of Ichthyophonus infection on spawning success of Yukon River Chinook salmon Oncorhynchus tshawytscha

2013 ◽  
Vol 106 (3) ◽  
pp. 207-215 ◽  
Author(s):  
T Hamazaki ◽  
E Kahler ◽  
BM Borba ◽  
T Burton
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Yukon River ◽  
Spawning Success

Using thalweg profiling to assess and monitor juvenile salmon (Oncorhynchus spp.) habitat in small streams

2006 ◽  
Vol 63 (7) ◽  
pp. 1515-1525 ◽  
Author(s):  
Brent Mossop ◽  
Michael J Bradford
Keyword(s):  
Chinook Salmon ◽  
Stream Flow ◽  
Gold Mining ◽  
Oncorhynchus Tshawytscha ◽  
Fish Habitat ◽  
Juvenile Chinook Salmon ◽  
Yukon River ◽  
Small Streams ◽  
Longitudinal Profiles ◽  
Small Tributary

Thalweg profiles are longitudinal profiles of the streambed elevation measured along the deepest portion of the stream. This technique has recently been advocated as a tool to assess and monitor fish habitat in streams because metrics calculated from thalweg profiles can provide useful information on habitat quality, and measurements are both repeatable and independent of stream flow. Relations between thalweg metrics and land use have also been documented. However, a relation between fish abundance and thalweg metrics has not been established. To develop this relation, we surveyed thalweg profiles and sampled juvenile Chinook salmon (Oncorhynchus tshawytscha) density in 14 reaches of small tributary streams of the upper Yukon River. Chinook salmon density was correlated with three thalweg metrics. Two of these metrics — length in residual pool and mean maximum residual pool depth — provided useful measures of pool extent and quality and useful information on Chinook salmon habitat. Thalweg metrics differed between these undisturbed streams and reaches in streams affected by placer gold mining. These results suggest that thalweg profiling provides a useful tool to assess and monitor fish habitat in small streams.

Low productivity of Chinook salmon strongly correlates with high summer stream discharge in two Alaskan rivers in the Yukon drainage

2015 ◽  
Vol 72 (8) ◽  
pp. 1125-1137 ◽  
Author(s):  
Jason R. Neuswanger ◽  
Mark S. Wipfli ◽  
Matthew J. Evenson ◽  
Nicholas F. Hughes ◽  
Amanda E. Rosenberger
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Population Declines ◽  
Environmental Predictors ◽  
High Discharge ◽  
Stream Discharge ◽  
Yukon River ◽  
Stock Recruitment ◽  
Sources Of Variation ◽  
Major Floods

Yukon River Chinook salmon (Oncorhynchus tshawytscha) populations are declining for unknown reasons, creating hardship for thousands of stakeholders in subsistence and commercial fisheries. An informed response to this crisis requires understanding the major sources of variation in Chinook salmon productivity. However, simple stock–recruitment models leave much of the variation in this system’s productivity unexplained. We tested adding environmental predictors to stock–recruitment models for two Yukon drainage spawning streams in interior Alaska — the Chena and Salcha rivers. Low productivity was strongly associated with high stream discharge during the summer of freshwater residency for young-of-the-year Chinook salmon. This association was more consistent with the hypothesis that sustained high discharge negatively affects foraging conditions than with acute mortality during floods. Productivity may have also been reduced in years when incubating eggs experienced major floods or cold summers and falls. These freshwater effects — especially density dependence and high discharge — helped explain population declines in both rivers. They are plausible as contributors to the decline of Chinook salmon throughout the Yukon River drainage.

Mitochondrial DNA Variation in Chinook (Oncorhynchus tshawytscha) and Chum Salmon (O. keta) Detected by Restriction Enzyme Analysis of Polymerase Chain Reaction (PCR) Products

1993 ◽  
Vol 50 (4) ◽  
pp. 708-715 ◽  
Author(s):  
Matthew A. Cronin ◽  
William J. Spearman ◽  
Richard L. Wilmot ◽  
John C. Patton ◽  
John W. Bickham
Keyword(s):  
Polymerase Chain Reaction ◽  
Mitochondrial Dna ◽  
Chinook Salmon ◽  
Chum Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Vancouver Island ◽  
Chain Reaction ◽  
Dna Variation ◽  
Yukon River ◽  
Polymerase Chain

We analyzed intraspecific mitochondrial DNA variation in chinook salmon (Oncorhynchus tshawytscha) from drainages in the Yukon River (Alaska and Yukon Territory), the Kenai River (Alaska), and Oregon and California rivers; and chum salmon (O. keta) from the Yukon River and Vancouver Island, and Washington rivers. For each species, three different portions of the mtDNA molecule were amplified separately using the polymerase chain reaction and then digested with at least 19 restriction enzymes. Intraspecific sequence divergences between haplotypes were less than 0.01 base substitution per nucleotide. Nine chum salmon haplotypes were identified. Yukon River chum salmon stocks displayed more haplotypes (eight) than the stocks of Vancouver Island and Washington (two). The most common chum salmon haplotype occurred in all areas. Seven chinook salmon haplotypes were identified. Four haplotypes occurred in the Yukon and Kenai rivers and four occurred in Oregon/California, with only one haplotype shared between the regions. Sample sizes were too small to quantify the degree of stock separation among drainages, but the patterns of variation that we observed suggest utility of the technique in genetic stock identification.

scholarly journals Evidence of prevalent heat stress in Yukon River Chinook salmon

2020 ◽  
Vol 77 (12) ◽  
pp. 1878-1892
Author(s):  
Vanessa R. von Biela ◽  
Lizabeth Bowen ◽  
Stephen D. McCormick ◽  
Michael P. Carey ◽  
Daniel S. Donnelly ◽  
...  
Keyword(s):  
Heat Stress ◽  
Chinook Salmon ◽  
Pacific Salmon ◽  
Adult Mortality ◽  
Early Mortality ◽  
Population Abundance ◽  
Yukon River ◽  
Salmon Population ◽  
Northern Pacific ◽  
Spawning Success

Migrating adult Pacific salmon (Oncorhynchus spp.) are sensitive to warm water (>18 °C), with a range of consequences from decreased spawning success to early mortality. We examined the proportion of Yukon River Chinook salmon (O. tshawytscha) exhibiting evidence of heat stress to assess the potential that high temperatures contribute to freshwater adult mortality in a northern Pacific salmon population. Water temperatures greater than 18 °C have occurred almost annually in the Yukon River and correspond with low population abundance since the 1990s. Using gene transcription products and heat shock protein 70 biomarkers validated by field experiment, we identified heat stress in half of Chinook salmon examined (54%, n = 477) across three mainstem locations and three tributaries in 2016–2017. Biomarkers tracked wide variation in water temperature (14–23 °C) within a tributary. The proportion of salmon with heat stress differed between years at four of the six locations, with more prevalent heat stress in the warmer year. This work demonstrates that warming water temperatures are currently affecting northern populations of Pacific salmon.

Catalog of Chinook Salmon Spawning Areas in Yukon River Basin in Canada and United States

2017 ◽  
Vol 8 (2) ◽  
pp. 558-586 ◽  
Author(s):  
Randy J. Brown ◽  
Al von Finster ◽  
Robert J. Henszey ◽  
John H. Eiler
Keyword(s):  
United States ◽  
River Basin ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
The United States ◽  
Maximum Effect ◽  
Yukon River ◽  
Spawning Areas ◽  
Yukon River Basin ◽  
Major Producer

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.

Sign in / Sign up

Export Citation Format

Share Document