Kudoa thyrsites (Gilchrist, 1924) (Myxozoa) in the cardiac muscle of Pacific salmon (Oncorhynchus spp.) and steelhead trout (Salmo gairdneri)

1989 ◽  
Vol 67 (2) ◽  
pp. 341-342 ◽  
Author(s):  
Z. Kabata ◽  
D. J. Whitaker
Keyword(s):  
British Columbia ◽  
Cardiac Muscle ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Salmo Gairdneri ◽  
Oncorhynchus Keta ◽  
Steelhead Trout ◽  
Myxozoan Parasite ◽  
Kudoa Thyrsites ◽  
Pacific Salmonids

An examination of the cardiac muscle of returning adults of all species of British Columbia Pacific salmonids, including steelhead trout (Salmo gairdneri), for infection by the myxozoan parasite Kudoa thyrsites showed that all species but chum (Oncorhynchus keta) and sockeye (Oncorhynchus nerka) are susceptible to infection. The prevalence of observed infection was low. Its intensity was not determined, but the small numbers of spores observed suggest that it was low. The possible causes of these observations are discussed.

Fine structure of the external egg membrane of five species of Pacific salmon and steelhead trout

1985 ◽  
Vol 63 (3) ◽  
pp. 552-566 ◽  
Author(s):  
E. P. Groot ◽  
D. F. Alderdice
Keyword(s):  
Fine Structure ◽  
Chum Salmon ◽  
Pacific Salmon ◽  
Salmo Gairdneri ◽  
Membrane Thickness ◽  
Steelhead Trout ◽  
Outermost Layer ◽  
Additional Layer ◽  
Egg Membrane ◽  
Pore Canals

Fine structure of the external egg membrane of five species of Pacific salmon (sockeye, Oncorhynchus nerka; pink, O. gorbuscha; chum, O. keta; coho, O. kisutch; and chinook, O. tshawytscha) and the anadromous steelhead trout (Salmo gairdneri), is examined and compared using the scanning electron microscope. Membrane thickness in fixed material varies for the six species as follows (micrometres, [Formula: see text]): sockeye, 34.15 ± 0.15; pink, 61.64 ± 1.53; chum, 53.05 ± 0.33; coho, 27.96 ± 0.48; chinook, 50.82 ± 0.74; steelhead, 30.74 ± 0.11. The membrane consists of a thin outermost layer, the externus, 0.2–0.3 μm thick, and the internus, 24–55 μm thick, which constitutes the remainder of the membrane. In sockeye, pink, and chum salmon and steelhead trout, an additional layer 3–8 μm thick, the "subinternus," occurs beneath the internus. The entire membrane appears fibrous except for the thin and apparently solid externus. Pores in both the inner and outer surfaces are arranged in a hexagonal pattern and are connected by pore canals traversing the membrane. Except in the sockeye, plugs commonly were seen blocking the external openings of the pore canals. Significance of the egg membrane fine structure is considered in relation to several of its roles in the water-activated egg: semipermeability, retention of internal pressure, and mechanical protection. A structural and functional analogy is drawn between the fine structure of the salmonid egg membrane and the mammalian aorta.

Effect of Stocking Density on the Survival, Growth, and Dispersal of Steelhead Trout Fry (Salmo gairdneri)

1987 ◽  
Vol 44 (2) ◽  
pp. 271-281 ◽  
Author(s):  
Jeremy M. B. Hume ◽  
Eric A. Parkinson
Keyword(s):  
British Columbia ◽  
Overall Survival ◽  
Stocking Density ◽  
Mortality Rates ◽  
Wild Fish ◽  
Density Effect ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Density Dependent ◽  
Coastal British Columbia

In a coastal British Columbia stream a stocking density of between 0.3 and 0.7 fry/m2 maximized the production of steelhead trout (Salmo gairdneri) parr and smolts. A severe autumn flood doubled the mortality rates of fry stocked at densities of 0.7 fry/m2 or higher but had little effect on fry stocked at lower densities (<0.15 fry/m2). Overall survival to smolts appeared to be lower than measured elsewhere for wild fish (2 vs. 4.5 – 18%). The proportion (<10%) of surviving fry found below the stocked sections was considered to be an indicator of potential displacement mortality in streams with no vacant downstream areas. This downstream dispersal was not density dependent and was small in comparison with the mortality of nondispersing fish. Although initial fry and parr sizes were density dependent, there was no detectable density effect on older parr or smolt sizes.

Genetic Variation in Populations of Steelhead Trout (Salmo gairdneri) in British Columbia

1984 ◽  
Vol 41 (10) ◽  
pp. 1412-1420 ◽  
Author(s):  
Eric A. Parkinson
Keyword(s):  
British Columbia ◽  
Genetic Variants ◽  
Large Scale ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Isolated Populations ◽  
Gene Frequencies ◽  
Geographic Scale ◽  
Biochemical Genetic ◽  
Pattern Of Variation

The geographic distributions of biochemical genetic variants at four loci in indigenous British Columbia steelhead (Salmo gairdneri) populations indicated that there was a large-scale subdivision of the species into three major groups. At intermediate geographic scales, gene frequencies were uniform over unexpectedly large areas, but at the smallest geographic scale, significant differentiation was observed between populations in adjacent streams. This pattern of variation supports the view that this species is subdivided into a large number of semi-isolated populations each having the potential to evolve adaptations to local environmental conditions.

Trichodina truttae Mueller, 1937 (Ciliophora: Peritrichida), a common pathogenic ectoparasite of cultured juvenile salmonid fishes in British Columbia: redescription and examination by scanning electron microscopy

1984 ◽  
Vol 62 (9) ◽  
pp. 1842-1848 ◽  
Author(s):  
J. R. Arthur ◽  
L. Margolis
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
British Columbia ◽  
Pacific Salmon ◽  
Salmo Gairdneri ◽  
Diagnostic Features ◽  
Detailed Surface ◽  
Juvenile Pacific Salmon ◽  
Oral Surface ◽  
Scanning Electron

The trichodinid ciliate Trichodina truttae Mueller, 1937 is redescribed from silver-impregnated specimens collected from the skin of cultured juvenile Pacific salmon (Oncorhynchus spp.) and steelhead trout (Salmo gairdneri) from British Columbia, and its detailed surface topography was examined by scanning electron microscopy (SEM). Diagnostic features evident by light microscopy are the large size (body diameter 114–179 μm), high denticle number (28–30), and high number (about 20) of radial pins per denticle. Especially noteworthy characters revealed by SEM that may be important for species identification are the presence of radial ridges on the oral surface and two markedly different lengths of cilia within the adoral ciliary spiral. This is the first verified report of T. truttae from Canada.

Homing in Wild Sockeye Salmon (Oncorhynchus nerka) Populations as Inferred from Differences in Parasite Prevalance and Allozyme Allele Frequencies

1987 ◽  
Vol 44 (11) ◽  
pp. 1963-1971 ◽  
Author(s):  
T. P. Quinn ◽  
C. C. Wood ◽  
L. Margolis ◽  
B. E. Riddell ◽  
K. D. Hyatt
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Genetic Differences ◽  
Allele Frequencies ◽  
Wild Populations ◽  
Central Coast ◽  
Barkley Sound ◽  
Quantitative Estimates

Although it is widely accepted that adult Pacific salmon (Oncorhynchus spp.) spawn in their natal stream, there are few quantitative estimates of homing precision in wild populations. The prevalence of two myxosporean parasites, Myxobolus neurobius and Henneguya salminicola, indicated very precise homing in certain sockeye salmon (O. nerka) populations in British Columbia (Long and Owikeno lakes on the central coast and Sproat, Great Central, and Henderson lakes on Barkley Sound, Vancouver Island). These populations were also sampled for electrophoretic differences at 23 loci. Genetic differences were found among all five populations, and estimates of straying from these data corroborated the parasitological evidence that straying is rare (< 1%).

scholarly journals Genome assembly, transcriptome and SNP database for chum salmon (Oncorhynchus keta)

2021 ◽  
Author(s):  
Eric B Rondeau ◽  
Kris A. Christensen ◽  
Dionne Sakhrani ◽  
Carlo A Biagi ◽  
Mike Wetklo ◽  
...  
Keyword(s):  
British Columbia ◽  
Linkage Group ◽  
Genome Assembly ◽  
Chum Salmon ◽  
Pacific Salmon ◽  
Gene Annotation ◽  
Oncorhynchus Keta ◽  
Specific Level ◽  
Genome Wide ◽  
The Pacific

Chum salmon (Oncorhynchus keta) is the species with the widest geographic range of the anadromous Pacific salmonids,. Chum salmon is the second largest of the Pacific salmon, behind Chinook salmon, and considered the most plentiful Pacific salmon by overall biomass. This species is of significant commercial and economic importance: on average the commercial chum salmon fishery has the second highest processed value of the Pacific salmon within British Columbia. The aim of this work was to establish genomic baseline resources for this species. Our first step to accomplish this goal was to generate a chum salmon reference genome assembly from a doubled-haploid chum salmon. Gene annotation of this genome was facilitated by an extensive RNA-seq database we were able to create from multiple tissues. Range-wide resequencing of chum salmon genomes allowed us to categorize genome-wide geographic variation, which in turn reinforced the idea that genetic differentiation was best described on a regional, rather than at a stock-specific, level. Within British Columbia, chum salmon regional groupings were described at the conservation unit (CU) level, and there may be substructure within particular CUs. Genome wide associations of phenotypic sex to SNP genetic markers identified two clear peaks, a very strong peak on Linkage Group 15, and another on Linkage Group 3. With these new resources, we were better able to characterize the sex-determining region and gain further insights into sex determination in chum salmon and the general biology of this species.

scholarly journals Differential infestation of juvenile Pacific salmon by parasitic sea lice in British Columbia, Canada

2020 ◽  
Vol 77 (12) ◽  
pp. 1960-1968
Author(s):  
Cole B. Brookson ◽  
Martin Krkošek ◽  
Brian P.V. Hunt ◽  
Brett T. Johnson ◽  
Luke A. Rogers ◽  
...  
Keyword(s):  
British Columbia ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Host Specialization ◽  
Sea Lice ◽  
Oncorhynchus Keta ◽  
Lepeophtheirus Salmonis ◽  
Fraser River ◽  
Farmed Salmon ◽  
Louse Species

Fraser River Pacific salmon have declined in recent decades, possibly from parasitism by sea lice (Caligus clemensi and Lepeophtheirus salmonis). We describe the abundance of both louse species infesting co-migrating juvenile pink (Oncorhynchus gorbuscha), chum (Oncorhynchus keta), and sockeye (Oncorhynchus nerka) salmon over 5 years in the Discovery Islands and Johnstone Strait, British Columbia. The generalist louse, C. clemensi, was 5, 7, and 39 times more abundant than the salmonid specialist, L. salmonis, on pink, chum, and sockeye salmon, respectively. Caligus clemensi abundance was higher on pink salmon (0.45, 95% CI: 0.38–0.55) and sockeye (0.39, 95% CI: 0.33–0.47) than on chum salmon. Lepeophtheirus salmonis abundance was highest on pink salmon (0.09, 95% CI = 0.06–0.15). Caligus clemensi had higher abundances in Johnstone Strait than in the Discovery Islands. These results suggest differences in host specialization and transmission dynamics between louse species. Because both lice infest farmed salmon, but only C. clemensi infests Pacific herring (Clupea pallasii), conservation science and management regarding lice and Fraser River salmon should further consider C. clemensi and transmission from farmed salmon and wild herring.

Ceratomyxa shasta Noble, 1950 (Myxozoa: Myxosporea) present in the Fraser River system of British Columbia

1983 ◽  
Vol 61 (9) ◽  
pp. 1991-1994 ◽  
Author(s):  
T. E. McDonald
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Drainage Basin ◽  
Coho Salmon ◽  
Cutthroat Trout ◽  
River System ◽  
Salmo Gairdneri ◽  
Fraser River ◽  
Steelhead Trout

An examination of 220 chinook salmon (Oncorhynchus tshawytscha), 84 coho salmon (O. kisutch), 145 steelhead trout (Salmo gairdneri), and 21 cutthroat trout (S. clarki) for Ceratomyxa shasta (Myxozoa: Myxosporea) from 16 localities in the Fraser River drainage, British Columbia, showed that at all sites examined these salmonid species were infected, with a prevalence ranging between 11 and 100%. The study concludes that C. shasta, the causative agent of the salmonid disease ceratomyxosis, is widely distributed in the Fraser drainage basin and discusses these results in relation to proposed fish culture in the region.

An Aberrant Strain of the Bacterial Fish Pathogen Aeromonas salmonicida Isolated from a Marine Host, the Sablefish (Anoplopoma fimbria), and from Two Species of Cultured Pacific Salmon

1971 ◽  
Vol 28 (10) ◽  
pp. 1629-1634 ◽  
Author(s):  
T. P. T. Evelyn
Keyword(s):  
Marine Fish ◽  
Brackish Water ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Aeromonas Salmonicida ◽  
Oncorhynchus Keta ◽  
Fish Pathogen ◽  
Anoplopoma Fimbria ◽  
Diseased Fish ◽  
Causative Bacterium

Biochemically unique strains of the causative bacterium (Aeromonas salmonicida) of furunculosis in fish are described. The strains were first isolated from a marine host, the sablefish, Anoplopoma fimbria, and later, from sockeye (Oncorhynchus nerka) and chum (Oncorhynchus keta) salmon. The strains were essentially identical, and although always isolated from diseased fish cultured in sea or brackish water, they behaved like typical freshwater bacteria.The outbreaks of furunculosis in local fish-culture facilities were rare events that are thought to have resulted from import of the pathogen in wild carrier fish. In the case of the sablefish that was captured at sea shortly before its death, the infection appears to represent the first instance of spontaneous furunculosis in a marine fish.

The life histories and trophic relationships of the Trichoptera of Marion Lake, British Columbia

1971 ◽  
Vol 49 (5) ◽  
pp. 623-635 ◽  
Author(s):  
Michael J. Winterbourn
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Life Histories ◽  
Oncorhynchus Nerka ◽  
Trophic Relationships ◽  
Salmo Gairdneri ◽  
Taricha Granulosa ◽  
Kokanee Salmon ◽  
Competitive Species ◽  
Species Being

Life histories and trophic relationships of Trichoptera were studied in a small British Columbia lake. Larvae of 10 caddis species were primarily sediment feeders, 2 were leaf feeders, 3 carnivores, and 1 Banksiola crotchi, an algal feeder in early instars and predaceous in later ones. The final instar larvae of potentially competitive species tended to be separated in time. Caddis larvae were an important component of the diet of rainbow trout (Salmo gairdneri), species being preyed upon sequentially as their later instars appeared in the lake. Larvae were also important as prey of the salamander Taricha granulosa but were less significant in the diets of kokanee salmon (Oncorhynchus nerka) and a second salamander Ambystoma gracile.

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