scholarly journals Factors Affecting the Migration of Juvenile Chum Salmon (Oncorhynchus keta) from the Coast of Hokkaido to the Okhotsk Sea

2021 ◽  
Author(s):  
Tomonori Azumaya ◽  
Hiroshi Kuroda ◽  
Tatuya Unuma ◽  
Takashi Yokota ◽  
Shigehiko Urawa
Keyword(s):  
Chum Salmon ◽  
Oncorhynchus Keta ◽  
Okhotsk Sea ◽  
Factors Affecting ◽  
Chum Salmon Oncorhynchus Keta ◽  
Juvenile Chum Salmon

scholarly journals Neural Stem Cells/Neuronal Precursor Cells and Postmitotic Neuroblasts in Constitutive Neurogenesis and After ,Traumatic Injury to the Mesencephalic Tegmentum of Juvenile Chum Salmon, Oncorhynchus keta

2020 ◽  
Vol 10 (2) ◽  
pp. 65
Author(s):  
Pushchina ◽  
Kapustyanov ◽  
Varaksin
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Progenitor Cells ◽  
Chum Salmon ◽  
Precursor Cells ◽  
Oncorhynchus Keta ◽  
Neuronal Precursor ◽  
Chum Salmon Oncorhynchus Keta ◽  
Neuronal Precursor Cells ◽  
Juvenile Chum Salmon

The proliferation of neural stem cells (NSCs)/neuronal precursor cells (NPCs) and the occurrence of postmitotic neuroblasts in the mesencephalic tegmentum of intact juvenile chum salmon, Oncorhynchus keta, and at 3 days after a tegmental injury, were studied by immunohistochemical labeling. BrdU+ constitutive progenitor cells located both in the periventricular matrix zone and in deeper subventricular and parenchymal layers of the brain are revealed in the tegmentum of juvenile chum salmon. As a result of traumatic damage to the tegmentum, the proliferation of resident progenitor cells of the neuroepithelial type increases. Nestin-positive and vimentin-positive NPCs and granules located in the periventricular and subventricular matrix zones, as well as in the parenchymal regions of the tegmentum, are revealed in the mesencephalic tegmentum of juvenile chum salmon, which indicates a high level of constructive metabolism and constitutive neurogenesis. The expression of vimentin and nestin in the extracellular space, as well as additionally in the NSCs and NPCs of the neuroepithelial phenotype, which do not express nestin in the control animals, is enhanced during the traumatic process. As a result of the proliferation of such cells in the post-traumatic period, local Nes+ and Vim+ NPCs clusters are formed and become involved in the reparative response. Along with the primary traumatic lesion, which coincides with the injury zone, additional Nes+ and Vim+ secondary lesions are observed to form in the adjacent subventricular and parenchymal zones of the tegmentum. In the lateral tegmentum, the number of doublecortin-positive cells is higher compared to that in the medial tegmentum, which determines the different intensities and rates of neuronal differentiation in the sensory and motor regions of the tegmentum, respectively. In periventricular regions remote from the injury, the expression of doublecortin in single cells and their groups significantly increases compared to that in the damage zone.

Size Selective Predation by Juvenile Chum Salmon (Oncorhynchus keta) on Epibenthic Prey in Puget Sound

1975 ◽  
Vol 32 (8) ◽  
pp. 1419-1429 ◽  
Author(s):  
Robert J. Feller ◽  
Victor W. Kaczynski
Keyword(s):  
Chum Salmon ◽  
Prey Selection ◽  
Puget Sound ◽  
Harpacticoid Copepod ◽  
Gut Contents ◽  
Oncorhynchus Keta ◽  
Size Spectrum ◽  
Natural Diet ◽  
Chum Salmon Oncorhynchus Keta ◽  
Juvenile Chum Salmon

Analysis of gut contents shows that juvenile (30–50 mm) chum salmon (Oncorhynchus keta) in Puget Sound select epibenthic organisms as their primary prey. Harpacticoid copepods numerically comprised over 80% of their natural diet in two areas studied, while terrestrial insects and cladocerans were most important in a third area. Calculation of Ivlev (1961) electivity coefficients indicated high selectivity factors for harpacticoids at one site (+0.59 to +0.94). Comparison of fish gut contents with quantitative epibenthic pump samples of available prey shows that prey selection was size related, but opposite that currently reported in the literature (e.g. Brooks and Dodson 1965); that is, the smaller of the available prey was preferred. This was true for both the total available prey size spectrum and the harpacticoid copepod fraction of the prey spectrum. Large numbers of prey eaten per fish suggest that juvenile chum salmon may exert high predation pressure on nearshore epibenthic organisms in Puget Sound during spring.

scholarly journals A Confocal Microscopic Study of Gene Transfer into the Mesencephalic Tegmentum of Juvenile Chum Salmon, Oncorhynchus keta, Using Mouse Adeno-Associated Viral Vectors

2021 ◽  
Vol 22 (11) ◽  
pp. 5661
Author(s):  
Evgeniya V. Pushchina ◽  
Ilya A. Kapustyanov ◽  
Ekaterina V. Shamshurina ◽  
Anatoly A. Varaksin
Keyword(s):  
Reticular Formation ◽  
Viral Vectors ◽  
Chum Salmon ◽  
Mesencephalic Reticular Formation ◽  
Laser Scanning Microscopy ◽  
Oncorhynchus Keta ◽  
Brain Cells ◽  
Nuclear Staining ◽  
Chum Salmon Oncorhynchus Keta ◽  
Juvenile Chum Salmon

To date, data on the presence of adenoviral receptors in fish are very limited. In the present work, we used mouse recombinant adeno-associated viral vectors (rAAV) with a calcium indicator of the latest generation GCaMP6m that are usually applied for the dorsal hippocampus of mice but were not previously used for gene delivery into fish brain. The aim of our work was to study the feasibility of transduction of rAAV in the mouse hippocampus into brain cells of juvenile chum salmon and subsequent determination of the phenotype of rAAV-labeled cells by confocal laser scanning microscopy (CLSM). Delivery of the gene in vivo was carried out by intracranial injection of a GCaMP6m-GFP-containing vector directly into the mesencephalic tegmentum region of juvenile (one-year-old) chum salmon, Oncorhynchus keta. AAV incorporation into brain cells of the juvenile chum salmon was assessed at 1 week after a single injection of the vector. AAV expression in various areas of the thalamus, pretectum, posterior-tuberal region, postcommissural region, medial and lateral regions of the tegmentum, and mesencephalic reticular formation of juvenile O. keta was evaluated using CLSM followed by immunohistochemical analysis of the localization of the neuron-specific calcium binding protein HuCD in combination with nuclear staining with DAPI. The results of the analysis showed partial colocalization of cells expressing GCaMP6m-GFP with red fluorescent HuCD protein. Thus, cells of the thalamus, posterior tuberal region, mesencephalic tegmentum, cells of the accessory visual system, mesencephalic reticular formation, hypothalamus, and postcommissural region of the mesencephalon of juvenile chum salmon expressing GCaMP6m-GFP were attributed to the neuron-specific line of chum salmon brain cells, which indicates the ability of hippocampal mammal rAAV to integrate into neurons of the central nervous system of fish with subsequent expression of viral proteins, which obviously indicates the neuronal expression of a mammalian adenoviral receptor homolog by juvenile chum salmon neurons.

Relationship between Otolith Microstructure and the Growth of Juvenile Chum Salmon (Oncorhynchus keta) under Different Prey Rations

1984 ◽  
Vol 41 (1) ◽  
pp. 126-133 ◽  
Author(s):  
Eric C. Volk ◽  
Robert C. Wissmar ◽  
Charles A. Simenstad ◽  
Douglas M. Eggers
Keyword(s):  
Growth Rate ◽  
Chum Salmon ◽  
Harpacticoid Copepod ◽  
Fish Growth ◽  
Oncorhynchus Keta ◽  
Otolith Microstructure ◽  
Increment Width ◽  
Chum Salmon Oncorhynchus Keta ◽  
Otolith Increment ◽  
Juvenile Chum Salmon

Effects of different prey taxa and daily ration levels on fish growth and the relationship between fish growth rate and mean otolith increment width were investigated for juvenile chum salmon (Oncorhynchus keta) in saltwater aquaria. Growth was positively correlated with ration, and food conversion efficiency was much higher for fish fed the harpacticoid copepod, Tigriopus californicus, than either the calanoid copepod, Pseudocalanus minutas, or the gammarid amphipod, Paramoera mohri. Otolith increments were produced daily for at least the first 160 d after hatching and there was a direct relationship between mean daily otolith increment width and fish growth rate. These results illustrate the possibility that otolith microstructure recapitulates juvenile chum growth histories during estuarine residence.

Energetic Constraints of Juvenile Chum Salmon (Oncorhynchus keta) Migrating in Estuaries

1988 ◽  
Vol 45 (9) ◽  
pp. 1555-1560 ◽  
Author(s):  
Robert C. Wissmar ◽  
Charles A. Simenstad
Keyword(s):  
Energy Intake ◽  
Chum Salmon ◽  
Juvenile Fish ◽  
Fish Growth ◽  
Oncorhynchus Keta ◽  
Chum Salmon Oncorhynchus Keta ◽  
Metabolic Costs ◽  
Juvenile Chum Salmon ◽  
The Difference ◽  
And Migration

Experiments on fish feeding behavior, field measures of fish sizes, migration rate, and prey resources, and an energetic growth model are used to evaluate the growth of juvenile chum salmon (Oncorhynchus keta) during outmigration in an estuary. Fish growth is defined as the difference between energy intake and metabolic costs. Energy intake is estimated from prey densities and foraging parameters, namely pursuit swimming speeds and energetic expenditures, and prey handling and encounter rates. Relationships for foraging parameters as functions of fish sizes and field prey abundance are used to evaluate energy intake by fish in the estuary. This information and calculations of metabolic costs allow predictions of fish growth during the migration. Results show that metabolic costs of maintenance and migration lie in a delicate balance with food intake and growth. Growth efficiencies exceeding 20% occur when metabolic expenditures decline and energy intake rates permit growth without depletion of the food supply. Defining such energetic balances facilitates characterization of carrying capacities of coastal ecosystems and has implications for enhancement of juvenile fish growth and, in turn, fish survival and production at sea.

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