Salmon Oncorhynchus Keta Research Articles

Transduction of Brain Neurons in Juvenile Chum Salmon (Oncorhynchus keta) with Recombinant Adeno-Associated Hippocampal Virus Injected into the Cerebellum during Long-Term Monitoring.

Corpus cerebelli in juvenile chum salmon is a multiprojective region of the brain connected via afferent and efferent projections with the higher regions of the brainstem and synencephalon, as well as with multiprojection regions of the medulla oblongata and spinal cord. During the postembryonic development of the cerebellum in chum salmon, Oncorhynchus keta, the lateral part of the juvenile cerebellum gives rise to the caudomedial part of the definitive cerebellum, which is consistent with the data reported for zebrafish and mouse cerebellum. Thus, the topographic organization of the cerebellum and its efferents are similar between fish (chum salmon and zebrafish) and mammals, including mice and humans. The distributions of recombinant adeno-associated viral vectors (rAAVs) after an injection of the base vector into the cerebellum have shown highly specific patterns of transgene expression in bipolar neurons in the latero-caudal lobe of the juvenile chum tectum opticum. The distribution of rAAVs in the dorsal thalamus, epithalamus, nucleus rotundus, and pretectal complex indicates the targeted distribution of the transgene via the thalamo-cerebellar projections. The detection of GFP expression in the cells of the epiphysis and posterior tubercle of juvenile chum salmon is associated with the transgene’s distribution and with the cerebrospinal fluid flow, the brain ventricles and its outer surface. The direct delivery of the rAAV into the central nervous system by intracerebroventricular administration allows it to spread widely in the brain. Thus, the presence of special projection areas in the juvenile chum salmon cerebellum, as well as outside it, and the identification of the transgene’s expression in them confirm the potential ability of rAAVs to distribute in both intracerebellar and afferent and efferent extracerebellar projections of the cerebellum.

Gene expression levels of synaptic exocytosis regulator synaptophysin in the brain and the olfactory organ of anadromous salmon.

Anadromous Pacific salmon (genus Oncorhynchus) are known for their homing behavior based on olfactory imprinting, which is formed during their seaward migration. Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE/Snare) complex is a minimum unit of vesicle exocytosis from the pre-synaptic membrane. Its component genes (synaptosome-associated protein 25, syntaxin 1, and vesicle-associated membrane protein 2) are more strongly expressed in the olfactory nervous system (olfactory epithelium, olfactory bulb, and telencephalon) at the migration stages related to olfactory imprinting and/or retrieval in salmon. This study focused on the mRNA synthesis of synaptophysin (Syp), one of the Snare regulatory factors. syp is strongly expressed in chum salmon (Oncorhynchus keta) olfactory nervous system during the seaward migration and temporarily increased during the homeward migration. In reference to our previous studies, these expression changes were similar to the snare genes in the chum salmon. Therefore, syp and Snare component genes were synchronously expressed reflecting the development and short-term plasticity of the olfactory nervous system that is essential for olfactory imprinting.

At-Sea Habitat Use of Rhinoceros Auklets Breeding in the Shelf Region of Eastern Hokkaido.

At-sea habitat use of breeding seabirds is strongly influenced by marine environmental features that vary over space and time. The use of bio-loggers allows researchers to track fine-scale movements of seabirds and provides opportunities to identify the primary factors affecting their area use for foraging. Using GPS loggers, we tracked chick-rearing rhinoceros auklets (Cerorhinca monocerata), which are wing-propelled divers, at Daikoku Island, eastern Hokkaido, Japan. The central phase for foraging activity on birds' trips was determined using a multiple change points model. To examine environmental factors explaining the distribution of the foraging phase, a generalized additive model was used where sea surface temperature, chlorophyll a concentration, bathymetry, and distance from the colony were explanatory variables. To obtain information supporting the behavioral tracking, prey items in the bill-loads of adult auklets were collected. We found that auklets foraged over the continental shelf shallower than the 200-m isobath and that distance from the colony was related to the area use. Adult auklets predominately brought back age-0 chum salmon (Oncorhynchus keta), which was abundant in coastal waters along southeast Hokkaido during the study period. Our findings indicate that rhinoceros auklets rearing chicks, hence visiting nests frequently, on Daikoku Island can find suitable feeding grounds nearby.

Estimating target strength of young chum salmon (Oncorhynchus keta)

Although chum salmon (Oncorhynchus keta) is an important fishery resource in Japan, acoustic methods cannot be applied to biomass estimation because the target strength (TS) is unknown. This study clarified the TS for each fork length (FL: 5.5–33.5 cm) of young chum salmon inhabiting the Japanese coastal area to the Bering Sea by measuring free-swimming fish. The size dependences of the TS values were TSmean = 20 log10 FL – 68.0, for both 38 and 120 kHz. This facilitated the estimation of biomass of young salmon using acoustic methods.

Comparative transcriptome profiling of selected osmotic regulatory proteins in the gill during seawater acclimation of chum salmon (Oncorhynchus keta) fry

Salmonid fishes, chum salmon (Oncorhynchus keta) have the developed adaptive strategy to withstand wide salinity changes from the early life stage. This study investigated gene expression patterns of cell membrane proteins in the gill of chum salmon fry on the transcriptome level by tracking the salinity acclimation of the fish in changing environments ranging from freshwater (0 ppt) to brackish water (17.5 ppt) to seawater (35 ppt). Using GO analysis of DEGs, the known osmoregulatory genes and their functional groups such as ion transport, transmembrane transporter activity and metal ion binding were identified. The expression patterns of membrane protein genes, including pump-mediated protein (NKA, CFTR), carrier-mediated protein (NKCC, NHE3) and channel-mediated protein (AQP) were similar to those of other salmonid fishes in the smolt or adult stages. Based on the protein-protein interaction analysis between transmembrane proteins and other related genes, we identified osmotic-related genes expressed with salinity changes and analyzed their expression patterns. The findings of this study may facilitate the disentangling of the genetic basis of chum salmon and better able an understanding of the osmophysiology of the species.

Оценка рыбного сырья как способ повышения информативности его характеристик

Introduction. The research features a detailed sensory evaluation of mass fishing objects belonging to different families, namely: the Macrouridae represented by the giant grenadier (Albatrossia pectoralis), the Herrings represented by the Pacific herring (Clupea pallasii), and the Salmons represented by the Keta salmon (Oncorhynchus keta). The research objective was to study the possibility of increasing the information content of the verbal description of fish raw materials in combination with a quantitative assessment of individual sensory indicators.
 Research objects and methods. The paper introduces the concept of detailed verbal description of group parameters of raw and heattreated muscle tissue. The description can increase the information capacity of sensory studies. The concept of extended description of fish raw material was added to the main sensory properties that describe color, smell, taste, and consistency. They include data on the properties of local areas with subcutaneous layer, dark muscles, fat layers, etc. Such a detailed verbal description gives an in-depth view of the sensory properties, which is part of general information on the functional and technological properties of the fish and a key factor in designing new developed products. To improve the objectivity of sensory research, the authors employed the method of quantitative evaluation.
 Results and discussion. The results were summed up as data on the significance coefficients established by experts, ranked, and expressed as a percentage. The significance coefficient is a method of quantitative regulation of the share of each sensory indicator in the general sensory evaluation. The research showed that the greater the number of group sensory indicators that characterize the object, the smaller and more similar their coefficients of significance, which dramatically reduces application opportunities. Therefore, significance coefficient proved a convenient means of measurement and visual presentation. However, the research was limited by the experimental conditions. 
 Conclusion. The study of the fish raw materials established, identified, and described individual sensory indicators that involved about twenty lexical units for raw material and thirty units for heat-treated muscle tissue. The individual sensory indicators characterized color, smell, and taste. They differed in the presence of several degrees of gradation and fit into a vertical three-level (sometimes two-level) classification. Group touch indicator of the consistency describes mostly single-level unit indicators with 4–6 lexical units. As a result, the detailed description of sensory properties of fish raw materials included 2–3 times more lexical units compared to the traditional description of fish raw materials in the special reference literature.

Salmon species identification via direct DNA sequencing of single amplicons

For Pacific salmonids, a key fisheries forensics and management goal is to identify individuals to specific species and potentially specific populations or geographic regions within species. Genetic variation can be used for both species and individual identification, and variation at single nucleotide polymorphisms (SNPs) within two specific DNA amplicons was used to distinguish among coho salmon (Oncorhynchus kisutch), Chinook salmon (Oncorhynchus tshawytscha), sockeye salmon (Oncorhynchus nerka), chum salmon (Oncorhynchus keta), pink salmon (Oncorhynchus gorbuscha), masu salmon (Oncorhynchus masou), steelhead/rainbow trout (Oncorhynchus mykiss), cutthroat trout (Oncorhynchus clarkii), and Atlantic salmon (Salmo salar). A total of 2510 individuals was evaluated from a Pacific rim distribution of populations for sockeye salmon, chum salmon, and pink salmon, whereas masu salmon samples were genotyped only from Japanese populations. Coho salmon, Chinook salmon, steehead trout, cutthroat trout, and Atlantic salmon samples were genotyped only from North American populations. All individual salmonids genotyped were assigned with 100% accuracy to their respective species via diagnostic homozygous SNP genotypes for each species except for cutthroat trout, where no diagnostic SNP genotypes were observed in the two amplicons evaluated.

Potential Role of the Magnetic Field on Homing in Chum Salmon (Oncorhynchus keta) Tracked from the Open Sea to Coastal Japan

Potential Role of the Magnetic Field on Homing in Chum Salmon (Oncorhynchus keta) Tracked from the Open Sea to Coastal Japan

Future Climate-Related Changes in Fish Species Composition Including Chum Salmon (Oncorhynchus keta) in Northern Japanese Waters, Inferred from Archaeological Evidence

Future Climate-Related Changes in Fish Species Composition Including Chum Salmon (Oncorhynchus keta) in Northern Japanese Waters, Inferred from Archaeological Evidence

Future Climate-Related Changes in Fish Species Composition Including Chum Salmon (Oncorhynchus keta) in Northern Japanese Waters, Inferred from Archaeological Evidence

Future Climate-Related Changes in Fish Species Composition Including Chum Salmon (Oncorhynchus keta) in Northern Japanese Waters, Inferred from Archaeological Evidence

Genetic stock identification of immature chum salmon (Oncorhynchus keta) in the western Bering Sea, 2004

Genetic stock identification studies have been widely applied to Pacific salmon species to estimate stock composition of complex mixed-stock fisheries. In a September-October 2004 survey, 739 chum salmon (Oncorhynchus keta) specimens were collected from 23 stations in the western Bering Sea. We determined the genetic stock composition of immature chum salmon based on the previous mitochondria DNA baseline. Each regional estimate was computed based on the conditional maximum likelihood method using 1,000 bootstrap resampling and then pooled to the major regional groups: Korea - Japan - Primorie (KJP) / Russia (RU) / Northwest Alaska (NWA) / Alaska Peninsula - Southcentral Alaska - Southeast Alaska - British Columbia - Washington (ONA). The stock composition of immature chum salmon in the western Bering Sea was a mix of 0.424 KJP, 0.421 RU, 0.116 NWA, and 0.039 ONA stocks. During the study period, the contribution of Asian chum salmon stocks gradually changed from RU to KJP stock. In addition, North American populations from NWA and ONA were small but present near the vicinity of the Russian coast and the Commander Islands, suggesting that the study areas in the western Bering Sea were an important migration route for Pacific chum salmon originating both from Asia and North America during the months of September and October. These results make it possible to better understand the chum salmon stock composition of the mixed-stock fisheries in the western Bering Sea and the stock-specific distribution pattern of chum salmon on the high-seas.

Chum salmon (Oncorhynchus keta) growth and temperature indices as indicators of the year-class strength of age-1 walleye pollock (Gadus chalcogrammus) in the eastern Bering Sea

Ecosystem-based fisheries management requires the development of physical and biological time series that index ocean productivity for stock assessment and recruitment forecasts for commercially important species. As recruitment in marine fish is related to ocean condition, we developed proxies for ocean conditions based on sea surface temperature (SST) and biometric measurements of chum salmon (Oncorhynchus keta) captured in the walleye pollock (Gadus chalcogrammus) fishery in the eastern Bering Sea in three periods (July 16–30, September 1–15 and September 16–30). The main purpose of this paper was to evaluate Pacific salmon (Oncorhynchus spp.) growth as a possible indicator of ocean conditions that, in turn, may affect age-1 walleye pollock recruitment. Marine growth rates of Pacific salmon are the result of a complex interplay of physical, biological and population-based factors that fish experience as they range through oceanic habitats. These growth rates can, therefore, be viewed as indicators of recent ocean productivity. Thus, our hypothesis was that estimated intra-annual growth in body weight of immature and maturing age-4 male and female chum salmon may be used as a biological indicator of variations in rearing conditions also experienced by age-0 walleye pollock; consequently, they may be used to predict the recruitment to age-1 in walleye pollock. Summer SSTs and chum salmon growth at the end of July and September explained the largest amount of variability in walleye pollock recruitment indicating that physical and biological indices of ocean productivity can index fish recruitment.

Characterization of sixteen polymorphic microsatellite DNA loci in the chum salmon (Oncorhynchus keta) isolated by next-generation sequencing

Chum salmon (Oncorhynchus keta) is an important fisheries resource around the North Pacific region. However, the genetic characteristics of this species mostly remain to be elucidated with competent molecular genetic markers for their effective resource management and sustainable use. A total of sixteen novel microsatellite markers in chum salmon were isolated using a next-generation sequencing approach. All loci were polymorphic with 6–21 alleles, with the observed and expected heterozygosities of 0.41667–0.97917 and 0.66184–0.92434, respectively. These new loci will provide a tool for examining the genetic diversity and population structure of chum salmon, which are an important information for the adaptive management of this species.

Stock identification and life history interpretation using trace element signatures in salmon otoliths

Chum salmon (Oncorhynchus keta) in the North Pacific Ocean are anadromous fish, and spend most of their life in the sea until spawning in natal streams. To identify the stock and habitat characteristics of chum salmon, the composition of chemical elements (Ca, Mn, Sr, Zn, and Ba) in otolith was examined using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). Two main types of analytical work have been carried out; discrete spot analysis and line scan analysis of otolith sections. Salmon otoliths were obtained from the eastern (Canada and USA) and western (Japan and Korea) North Pacific during 1997–1999 spawning seasons. Spot analysis of otolith cores demonstrated significant differences in the element concentration among countries (p = 0.003). Line scanning from the core to the margin showed that Sr concentrations were elevated at the core of the otoliths, decreased during the freshwater stage, increased suddenly at a certain point, and oscillated periodically towards the margin matching with year-ring. The elevated Sr concentration at the core may reflect the maternal contribution to the egg, and the oscillations toward the margin may reflect salinity gradients between onshore/offshore or north/south migrations. The Zn profiles also oscillated and corresponded to the annual ring of the otolith. However, the profiles of Sr and Zn oscillated oppositely after salmon migrated to saline water and the Zn uptake declined toward the rim of the otolith while Sr uptake increased.

The information maintenance of economic mechanisms of the Pacific salmons biodiversity preservation

Actual problem of creation of effective economic mechanisms of biodiversity preservation is the weakness of the cost estimation of economic functions of diversity of the wildlife exploitable objects. In the article the complex of simulation algorithmic models are considered for the cost evaluation of an intraspecific biodiversity of chum salmon (Oncorhynchus keta).

Effect of hypo-osmotic environmental changes on the expression of gonadotropin-releasing hormone, its receptor, and gonadotropin hormone subunit mRNA in adult chum salmon (Oncorhynchus keta)

Migrating fish such as salmonids are affected by external environmental factors and salinity changes are particularly important, influencing spawning migration. The aim of this study was to test whether changes in salinity would affect the expression of the hypothalamic-pituitary-gonadal (HPG) axis hormones (gonadotropin-releasing hormones (GnRHs) [salmon GnRH and chicken GnRH-II], GnRH receptors [GnRHR1 and GnRHR5], and mRNA of the gonadotropin hormone [GTH] subunits [GTHα, follicle stimulating hormone β, and luteinizing hormone β]) in chum salmon (Oncorhynchus keta). Fish were progressively transferred from seawater (SW) through 50% SW to freshwater (FW), and the relationship between the osmoregulatory hormone prolactin (PRL) and sexual maturation was determined. The expression and activity of HPG hormones and their receptors, and levels of estradiol-17β and PRL increased after fish were transferred to FW, demonstrating that changes in salinity stimulate the HPG axis and PRL production in migrating chum salmon. These findings reveal details about the role of the endocrine system in maintaining homeostasis and stimulating sexual maturation and reproduction in response to salinity changes in this species.

Fine-scale sampling reveals distinct isolation by distance patterns in chum salmon (Oncorhynchus keta) populations occupying a glacially dynamic environment

Populations with spatially restricted gene flow are characterized by genetic differentiation that may be positively correlated with the geographic distance separating populations, a pattern known as isolation by distance (IBD). Here we examined the fine-scale genetic structure of 66 chum salmon (Oncorhynchus keta) populations spawning in Alaska waterways and explored patterns of IBD using 90 nuclear and 3 mitochondrial single nucleotide polymorphisms. Estimating population structure of chum salmon in Alaska is of increasing concern because of fluctuating census sizes and the uncertain effects of harvest on specific populations. We hypothesized that IBD would be present because chum salmon spawn in coastal rivers that are distributed along a linear array and gene flow is spatially restricted due to homing. Evidence of very weak IBD was found throughout the region (R2 = 0.06, p < 0.0001) but the strength of the IBD relationship varied greatly over different spatial scales and geographic regions. Decomposed pairwise regression analyses identified nine outlier populations to regional IBD patterns, suggesting that geographic distance is not the only factor influencing genetic differentiation in the region. Instead, population structure appears to be heavily influenced by glacial history of the region and the presence of a glacial refugium on Kodiak Island.

Informativity of some of the molecular markers most frequently used in population genetics of salmonids

The genetic parameters of donor and artificial populations of Siberian salmon (Oncorhynchus keta) have been analyzed. The parameters were obtained Wvith the use of different molecular markers as well as mathematic modeling based on experimental data. The difference between results is explained by the different resolving power of individual markers and/or stochastic effects. It is assumed that these factors together with temporal differentiation of spawning salmonid populations and the stable interpopulation gene flow constrain resolution of methods based on the use of molecular markers and designated for the analysis of differentiation of salmonid populations.

Genetic stock identification of overwintering chum salmon in the North Pacific Ocean

Understanding stock and age-specific seasonal migrations of Pacific salmon during ocean residence is essential to both the conservation and management of this important resource. Based upon 11 microsatellites assayed on 265 individuals collected aboard international research surveys during winter 2009, we found substantial differences in the age-specific origin of chum salmon (Oncorhynchus keta) in the North Pacific Ocean. Overall, Asian stocks dominated the collections, however, ocean age 1 fish were primarily of Japanese origin and ocean age 2–3+ fish were predominantly of Russian origin. These results suggest that cohorts of chum salmon stocks migrate nonrandomly in the North Pacific Ocean and adjacent seas.

The genetic structure of chum salmon (Oncorhynchus keta Walbaum) populations inferred from the nucleotide variation of the mitochondrial DNA cytochrome b gene

The nucleotide sequences of a fragment of the mitochondrial DNA cytochrome b gene were determined in 12 chum salmon populations from the Russian Far East. The level of genetic diversity in the chum salmon populations from the Iturup Island, northern coast of the Sea of Okhotsk, and Anadyr' River was found to be higher than in the populations from Kamchatka and Sakhalin, which may be related to the history of their origin and dispersal. The proportions of intrapopulation genetic variability (F(ct)) and interpopulation genetic variability within the groups (F(sc)) account for 90.87 and 0.9%, respectively, and the intergroup component (F(st)) comprises 8.23%. The predominance of one haplotype, B1, which is common for all populations studied, and a low share of intergroup variability suggest the beginning of colonization by the species of the given region from a common source (group of founders) and a relatively recent time of divergence of the chum salmon populations from the region examined.