Spreading of River Water Guides Migratory Behavior of Homing Chum Salmon Oncorhynchus keta in Otsuchi Bay, a Narrow Inlet with Multiple River Flows

2019 ◽  
Vol 36 (6) ◽  
pp. 449
Author(s):  
Shigenori Nobata ◽  
Takashi Kitagawa ◽  
Kiyoshi Tanaka ◽  
Kosei Komatsu ◽  
Yoshinori Aoki ◽  
...  
Keyword(s):  
River Water ◽  
Chum Salmon ◽  
Oncorhynchus Keta ◽  
Migratory Behavior ◽  
River Flows ◽  
Otsuchi Bay ◽  
Chum Salmon Oncorhynchus Keta

Importance of Estuarine Residence for Adaptation of Chum Salmon (Oncorhynchus keta) Fry to Seawater

1984 ◽  
Vol 41 (5) ◽  
pp. 744-749 ◽  
Author(s):  
Munehico Iwata ◽  
Shichiko Komatsu
Keyword(s):  
Surface Layer ◽  
Brackish Water ◽  
Chum Salmon ◽  
Oncorhynchus Keta ◽  
Otsuchi Bay ◽  
Chum Salmon Oncorhynchus Keta ◽  
Salmon Fry ◽  
Seaward Migration ◽  
Subsequent Exposure ◽  
Salmon Hatchery

Within 24 h after release from the Otsuchi Salmon Hatchery in Japan, most chum salmon (Oncorhynchus keta) fry migrated the 1.7 km and were found in the surface layer (10–15‰ salinity) of the estuary. No fish were seen in the underlying seawater. Many fry remained in the brackish water for 2 d before migrating seaward. Plasma Na concentrations increased gradually from 134 to 156 mmol/L during seaward migration from the river to Otsuchi Bay. When fry were acclimated to one-third seawater for 3 and 6 h and then transferred to seawater, the Na concentration of the fry increased maximally to 161–172 mmol/L within 12 h. When they were acclimated to one-third seawater for 12 h, the Na concentrations reached the seawater-acclimated level without showing any peak; subsequent exposure to seawater did not cause any further change in plasma Na. Acclimation to isotonic estuary water for 12 h is thus sufficient for efficient adaptation of chum salmon fry to seawater.

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.

Effect of riverbed conditions on survival of planted eyed eggs in chum salmon Oncorhynchus keta

2016 ◽  
Vol 83 (2) ◽  
pp. 291-300 ◽  
Author(s):  
Masaya Iida ◽  
Satoshi Imai ◽  
Satoshi Katayama
Keyword(s):  
Chum Salmon ◽  
Oncorhynchus Keta ◽  
Chum Salmon Oncorhynchus Keta
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