Whirling Disease: Reviews and Current Topics

2002 ◽  
Keyword(s):  
River Basin ◽  
Columbia River ◽  
Fish Populations ◽  
Steelhead Trout ◽  
Adult Fish ◽  
Whirling Disease ◽  
Myxobolus Cerebralis ◽  
Hydroelectric Project ◽  
Natural Production ◽  
Deschutes River

<EM>ABSTRACT. </EM>Anadromous fish were excluded above Pelton Round Butte Hydroelectric Project (PRB Project), located midway (RM 100) on the Deschutes River in central Oregon, beginning in 1968. Reintroduction of these fish above the PRB Project is proposed to meet conservation concerns that arise from lack of natural production and separation of populations. One consideration, when moving fish groups that have been isolated one from the other for thirty years, is that of disease. The health of the fish populations above Round Butte Dam could be seriously jeopardized by the introduction of whirling disease. Straying hatchery steelhead trout <em>Oncorhynchus mykiss </em>were detected with <em>Myxobolus cerebralis </em>spores, in 1987, at Warm Springs National Fish Hatchery, below the PRB Project. <em>Myxobolus cerebralis </em>is established in tributaries of the upper Columbia River basin and of the Snake River basin, where some of these straying hatchery and wild steelhead trout may have originated. From 1997 to 2000, fish from the Deschutes River basin have been sampled for the presence of <em>M. cerebralis</em>. The parasite has been found in both straying hatchery and unmarked adult chinook salmon <em>O. tshawytscha </em>and steelhead trout. Presently there is no evidence of infection of resident fish or in returning adult fish originating from Round Butte Hatchery, although the potential for establishment of <em>M. cerebralis </em>in the Deschutes River watershed cannot be ruled out.

Propagated Fish in Resource Management

2004 ◽  
Keyword(s):  
Rainbow Trout ◽  
Infectious Hematopoietic Necrosis Virus ◽  
Fish Populations ◽  
Whirling Disease ◽  
Yersinia Ruckeri ◽  
Myxobolus Cerebralis ◽  
Infectious Hematopoietic Necrosis ◽  
Tetracapsuloides Bryosalmonae ◽  
Parasite Challenge

<em>Abstract.</em>—Laboratory challenges of two rainbow trout <em>Oncorhynchus mykiss </em>strains with <em>Myxobolus cerebralis </em>triactinomyxons confirm the resistance to whirling disease of the Hofer trout strain. Although the number of fish that became infected and developed clinical disease was similar for the Hofer and the Trout Lodge strains at all challenge doses, the median spore numbers were lower at all challenge doses for the Hofer rainbow trout. Parasite challenge doses required to produce lesions of high severity were 10-fold lower for the Trout Lodge strain (100 triactinomyxons) than the Hofer strain (1,000 triactinomyxons). Challenges of the Hofer strain with other common salmonid pathogens; the myxozoans <em>Ceratomyxa shasta </em>and <em>Tetracapsuloides bryosalmonae</em>, the bacterium <em>Yersinia ruckeri</em>, and the viruses Salmonid herpes-like virus type 1 and infectious hematopoietic necrosis virus demonstrate that the susceptibility of the Hofer strain was similar to what would be expected for other strains of rainbow trout, either domestic or wild. These pathogen challenges provide evidence that the Hofer trout present a low risk for introducing any pathogen that might be detrimental to native or established fish populations or further amplifying those that are endemic.

scholarly journals Whirling disease in the Crowsnest River: an emerging threat to wild salmonids in Alberta

2021 ◽  
pp. 1-14
Author(s):  
Clayton T. James ◽  
Marie F. Veillard ◽  
Amanda M. Martens ◽  
Emmanuel A. Pila ◽  
Alyssa Turnbull ◽  
...  
Keyword(s):  
Clinical Signs ◽  
Fish Populations ◽  
Tubifex Tubifex ◽  
Weight Of Evidence ◽  
Whirling Disease ◽  
Myxobolus Cerebralis ◽  
Parasite Life Cycle ◽  
Life Cycle Stages ◽  
Water Fish ◽  
Study Sites

We provide the first documented case of whirling disease (WD) impacts to wild, self-sustaining rainbow trout (RNTR, Oncorynchus mykiss) populations in Canada. Myxobolus cerebralis (Mc), the causative agent of WD, was first confirmed in Alberta in 2016. However, evidence of disease in local fish populations was unknown. Using a weight-of-evidence approach, we examined multiple parasite life cycle stages in the Crowsnest River, Alberta. Percentage of infected Tubifex tubifex worms actively shedding triactinomyxons (TAMs) exceeded known thresholds of Mc establishment and TAM densities instream exceeded thresholds known to cause ≥90% declines in RNTR populations. Mc was detected at 5 of 6 study sites in water, fish, and worms. Disease severity was highest in the lower watershed where 100% of sentinel fish tested positive for Mc 7 to 14 days post-exposure; up to 85% of wild fingerling RNTR showed clinical signs of disease and yearling trout were largely absent from the river suggesting reduced survival. Our findings indicate conditions necessary for outbreak of WD exist in Alberta, highlighting the need to consider this disease as an emerging threat to wild salmonid populations.

Population Structure of Columbia River Basin Chinook Salmon and Steelhead Trout

2004 ◽  
Vol 12 (2-3) ◽  
pp. 99-232 ◽  
Author(s):  
ERNEST L. BRANNON ◽  
MADISON S. POWELL ◽  
THOMAS P. QUINN ◽  
ANDRÉ TALBOT
Keyword(s):  
Population Structure ◽  
River Basin ◽  
Chinook Salmon ◽  
Columbia River ◽  
Columbia River Basin ◽  
Steelhead Trout

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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