a novel member of the family hepeviridae from cutthroat trout (oncorhynchus clarkii).beginning in 1988, the chinook salmon embryo (chse-214) cell line was used to isolate a novel virus from spawning adult trout in the state of california, usa. termed the cutthroat trout (oncorhynchus clarkii) virus (ctv), the small, round virus was not associated with disease, but was subsequently found to be present in an increasing number of trout populations in the western usa, likely by a combination of improved surveillance activities and the shipment of infected eggs to new locations. here ...201121458509
genetic differentiation of alaska chinook salmon: the missing link for migratory studies.most information about chinook salmon genetic diversity and life history originates from studies from the west coast usa, western canada and southeast alaska; less is known about chinook salmon from western and southcentral alaska drainages. populations in this large area are genetically distinct from populations to the south and represent an evolutionary legacy of unique genetic, phenotypic and life history diversity. more genetic information is necessary to advance mixed stock analysis applica ...201121429177
spatial, temporal and host factors structure the ceratomyxa shasta (myxozoa) population in the klamath river basin.the myxozoan parasite ceratomyxa shasta is a virulent pathogen of salmonid fish in the klamath river, oregon/california, usa. we previously defined four principal genotypes of the parasite (o, i, ii, iii) based on a trinucleotide repeat (atc)(0-3) in internal transcribed spacer region 1 sequences. genotypes occur in sympatry and show marked host preference: i in chinook salmon (oncorhynchus tschawytscha) and ii in non-native rainbow trout (o. mykiss). in the present study, we sequenced the paras ...201020601174
disparate infection patterns of ceratomyxa shasta (myxozoa) in rainbow trout (oncorhynchus mykiss) and chinook salmon (oncorhynchus tshawytscha) correlate with internal transcribed spacer-1 sequence variation in the parasite.ceratomyxa shasta is a virulent myxosporean parasite of salmon and trout in the pacific northwest of north america. the parasite is endemic in the klamath river, oregon/california, where a series of dams prevent movement of fish hosts between the upper and lower parts of the basin. ceratomyxa shasta exhibits a range of infection patterns in different fish species above and below the dams. we hypothesised that the variations in infection and disease are indicators that different strains of the pa ...201019895812
genotypes and phylogeographical relationships of infectious hematopoietic necrosis virus in california, usa.infectious hematopoietic necrosis virus (ihnv) contains 3 major genogroups in north america with discreet geographic ranges designated as upper (u), middle (m), and lower (l). a comprehensive genotyping of 237 ihnv isolates from hatchery and wild salmonids in california revealed 25 different sequence types (a to y) all in the l genogroup; specifically, the genogroup contained 14 sequence types that were unique to individual isolates as well as 11 sequence types representing 2 or more identical i ...200717933395
distribution and habitat characteristics of manayunkia speciosa and infection prevalence with the parasite ceratomyxa shasta in the klamath river, oregon-california.a survey for manayunkia speciosa, the freshwater polychaete host for the myxozoan parasite ceratomyxa shasta, was conducted from 2003 to 2005 as part of an integrated study of the epizootiology of ceratomyxosis in klamath river salmonids. substrata samples (n = 257) were collected in a variety of habitats from klamath lake to the mouth of the klamath river to document occurrence and relative abundance of the polychaete by habitat type and to estimate the prevalence of c. shasta within selected p ...200717436945
major histocompatibility complex differentiation in sacramento river chinook salmon.the chinook salmon of the sacramento river, california, have been reduced to a fraction of their former abundance because of human impact and use of the river system. here we examine the genetic variation at a major histocompatibility complex class ii exon in the four sacramento chinook salmon runs. examination of the alleles found in these and other chinook salmon revealed nucleotide patterns consistent with selection for amino acid replacement at the putative antigen-binding sites. we found a ...199910049927
effects of pyrethroid insecticides in urban runoff on chinook salmon, steelhead trout, and their invertebrate prey.pyrethroid insecticides can affect salmonids either indirectly through toxicity to their prey or directly by toxicity to the fish themselves. in support of a study on pyrethroid impacts to chinook salmon and steelhead trout in the american river (sacramento, california, usa), 96-h median effective concentration (ec50) and median lethal concentration (lc50) values for the pyrethroid bifenthrin were determined for taxa not traditionally used for toxicity testing but of interest as salmonid prey, i ...201525545717
genetic diversity of infectious hematopoietic necrosis virus from feather river and lake oroville, california, and virulence of selected isolates for chinook salmon and rainbow trout.infectious hematopoietic necrosis virus (ihnv) is a significant pathogen of young salmonid fishes worldwide but particularly within the historical range of the pacific northwest and california. in the sacramento and san joaquin river drainages of california, ihnv outbreaks in juvenile chinook salmon oncorhynchus tshawytscha have been observed regularly at large production hatcheries, including coleman national fish hatchery (established in 1941) and feather river state fish hatchery (frh; establ ...200718333482
longevity of ceratomyxa shasta and parvicapsula minibicornis actinospore infectivity in the klamath river.infectious ceratomyxa shasta and parvicapsula minibicornis actinospores were present in klamath river samples collected in april, may, and june 2005. juvenile chinook salmon oncorhynchus tshawytscha exposed to river water maintained at the ambient klamath river temperature for 0, 4, 24, 72, and 168 h (7 d) developed asymptomatic infections from both parasites. elevated water temperature (18 degrees c) in june may have reduced actinospore viability, as both c. shasta and p. minibicornis infection ...200718201047
candidate loci reveal genetic differentiation between temporally divergent migratory runs of chinook salmon (oncorhynchus tshawytscha).local adaptation is a dynamic process driven by selection that can vary both in space and time. one important temporal adaptation for migratory animals is the time at which individuals return to breeding sites. chinook salmon (oncorhynchus tshawytscha) are excellent subjects for studying the genetic basis of temporal adaptation because their high seasonal homing fidelity promotes reproductive isolation leading to the formation of local populations across diverse environments. we tested for adapt ...200717971087
pacific salmon extinctions: quantifying lost and remaining diversity.widespread population extirpations and the consequent loss of ecological, genetic, and life-history diversity can lead to extinction of evolutionarily significant units (esus) and species. we attempted to systematically enumerate extinct pacific salmon populations and characterize lost ecological, life history, and genetic diversity types among six species of pacific salmon (chinook [oncorhynchus tshawytscha], sockeye [o. nerka], coho [o. kisutch], chum [o. keta], and pink salmon [o. gorbuscha] ...200717650251
the impact of rice pesticides on the aquatic ecosystems of the sacramento river and delta (california).since the early 1980s, when molinate was demonstrated to have killed carp in agricultural drains, an intensive research effort has been undertaken to assess the impact of rice pesticides on aquatic ecosystems in the sacramento river and delta. no impact has been found that can be clearly attributed to rice pesticides. however, the rice insecticides methyl parathion and carbofuran, and probably also bufencarb, reached levels in the river and delta that, based on laboratory bioassays, would have b ...19999921140
modeling magnetic fields from a dc power cable buried beneath san francisco bay based on empirical measurements.the trans bay cable (tbc) is a ±200-kilovolt (kv), 400 mw 85-km long high voltage direct current (dc) buried transmission line linking pittsburg, ca with san francisco, ca (sf) beneath the san francisco estuary. the tbc runs parallel to the migratory route of various marine species, including green sturgeon, chinook salmon, and steelhead trout. in july and august 2014, an extensive series of magnetic field measurements were taken using a pair of submerged geometrics magnetometers towed behind a ...201626915084
persistent organic pollutants in forage fish prey of rhinoceros auklets breeding in puget sound and the northern california current.organochlorine contaminants in upper trophic-level consumers inhabiting puget sound are consistently higher than in those species inhabiting other west coast locations. we analyzed persistent organic pollutants (pops) in the six most common fish prey of rhinoceros auklets breeding on protection island (puget sound), tatoosh island (wa coast), and destruction island (wa coast). wet-weight concentrations of pops ranged widely (pcbs: 1.6-25.0 ng/g; ddts: 0.2-56.0 ng/g; pbdes:<loq-49.0 ng/g), but ov ...201425103902
chinook salmon and green sturgeon migrate through san francisco estuary despite large distortions in the local magnetic field produced by bridges.empirical evidence exists that some marine animals perceive and orient to local distortions in the earth's main static geomagnetic field. the magnetic fields produced by undersea electric power cables that carry electricity from hydrokinetic energy sources to shore-based power stations may produce similar local distortions in the earth's main field. concerns exist that animals migrating along the continental shelves might orient to the magnetic field from the cables, and move either inshore or o ...201728575021
relationship between temperature and ceratomyxa shasta -induced mortality in klamath river salmonids.water temperature influences almost every biological and physiological process of salmon, including disease resistance. in the klamath river (california), current thermal conditions are considered sub-optimal for juvenile salmon. in addition to borderline temperatures, these fish must contend with the myxozoan parasite ceratomyxa shasta , a significant cause of juvenile salmonid mortality in this system. this paper presents 2 studies, conducted from 2007 to 2010, that examine thermal effects on ...201222746389
transmission and persistence of ceratonova shasta genotypes in chinook salmon.ceratonova shasta is a myxozoan parasite of salmon and trout transmitted by waterborne actinospores. based on dna sequence data and host specificity, 4 distinct parasite genotypes are recognized. genotypes i and ii are common in the lower reaches of the klamath river, oregon-california, but only infection by genotype i causes mortality in chinook salmon. we conducted sentinel fish exposures and determined genotype composition in river water during exposure, and in fish gills, intestine, and tank ...201424945751
production of ceratonova shasta myxospores from salmon carcasses: carcass removal is not a viable management option.severe infection by the endemic myxozoan parasite, ceratonova (synonym, ceratomyxa) shasta, has been associated with declines in and impaired recovery efforts of populations of fall-run chinook salmon oncorhynchus tshawytscha in the klamath river, california. the parasite has a complex life cycle involving a polychaete worm host as well as a salmon host. myxospore transmission of this parasite, from salmon to polychaete, is a life cycle step during which there is a potential for applied disease ...201627064587
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