Landscape-level constraints on recruitment of chinook salmon (Oncorhynchus tshawytscha) in the Columbia River basin, USA

2003 ◽  
Vol 13 (1) ◽  
pp. 35-49 ◽  
Author(s):  
James Regetz
Keyword(s):  
River Basin ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Columbia River ◽  
Columbia River Basin ◽  
Landscape Level

scholarly journals Virulence and Infectivity of UC, MD, and L Strains of Infectious Hematopoietic Necrosis Virus (IHNV) in Four Populations of Columbia River Basin Chinook Salmon

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 701
Author(s):  
Daniel G. Hernandez ◽  
William Brown ◽  
Kerry A. Naish ◽  
Gael Kurath
Keyword(s):  
River Basin ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Columbia River ◽  
Infectious Hematopoietic Necrosis Virus ◽  
Host Susceptibility ◽  
Columbia River Basin ◽  
Species Variation ◽  
Necrosis Virus ◽  
Infectious Hematopoietic Necrosis

Infectious Hematopoietic Necrosis Virus (IHNV) infects juvenile salmonid fish in conservation hatcheries and aquaculture facilities, and in some cases, causes lethal disease. This study assesses intra-specific variation in the IHNV susceptibility of Chinook salmon (Oncorhynchus tshawytscha) in the Columbia River Basin (CRB), in the northwestern United States. The virulence and infectivity of IHNV strains from three divergent virus genogroups are measured in four Chinook salmon populations, including spring-run and fall-run fish from the lower or upper regions of the CRB. Following controlled laboratory exposures, our results show that the positive control L strain had significantly higher virulence, and the UC and MD strains that predominate in the CRB had equivalently low virulence, consistent with field observations. By several experimental measures, there was little variation in host susceptibility to infection or disease. However, a small number of exceptions suggested that the lower CRB spring-run Chinook salmon population may be less susceptible than other populations tested. The UC and MD viruses did not differ in infectivity, indicating that the observed asymmetric field prevalence in which IHNV detected in CRB Chinook salmon is 83% UC and 17% MD is not due to the UC virus being more infectious. Overall, we report little intra-species variation in CRB Chinook salmon susceptibility to UC or MD IHNV infection or disease, and suggest that other factors may instead influence the ecology of IHNV in the CRB.

Influence of pinniped-caused injuries on the survival of adult Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) in the Columbia River basin

2011 ◽  
Vol 68 (9) ◽  
pp. 1615-1624 ◽  
Author(s):  
George P. Naughton ◽  
Matthew L. Keefer ◽  
Tami S. Clabough ◽  
Michael A. Jepson ◽  
Steven R. Lee ◽  
...  
Keyword(s):  
Oncorhynchus Mykiss ◽  
River Basin ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Columbia River ◽  
Columbia River Basin ◽  
Small Fish ◽  
Steelhead Trout ◽  
Large Fish ◽  
Density Dependent

Increasing pinniped abundance in the Pacific Northwest has coincided with population declines of Pacific salmon ( Oncorhynchus  spp.) and steelhead trout ( Oncorhynchus mykiss ), and concentrated predation may affect the recovery of some threatened and endangered salmonid stocks. We used radiotelemetry to evaluate pinniped-caused injury effects on migration survival of 17 007 adult Columbia River Chinook salmon ( Oncorhynchus tshawytscha ) and steelhead trout. Injuries from pinnipeds were common (mean injury rate across 29 run-years = 36.5%) and were most common for spring Chinook salmon and steelhead trout. Injury was not consistently associated with adult survival to spawning tributaries, but some negative survival effects were detected. Pinniped-caused injury rates decreased as annual run sizes increased, indicating density-dependent or saturation effects. Within a run, large fish generally had a higher injury incidence than small fish, suggesting pinnipeds targeted large fish or more efficiently captured small fish. Seasonal, size-dependent, and density-dependent results imply that pinniped effects likely differ widely among salmonid populations within the Columbia River basin. A better understanding of these effects is needed to guide management and conservation strategies.

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