Phenotypic Differentiation in Seasonal Ecotypes of Chum Salmon, Oncorhynchus keta

1991 ◽  
Vol 48 (4) ◽  
pp. 661-671 ◽  
Author(s):  
Ross F. Tallman ◽  
Michael C. Healey
Keyword(s):  
Egg Size ◽  
Chum Salmon ◽  
Downstream Migration ◽  
Oncorhynchus Keta ◽  
Age At Maturity ◽  
Similar Time ◽  
Phenotypic Differentiation ◽  
Chum Salmon Oncorhynchus Keta ◽  
Spawning Stock ◽  
Autumn And Winter

We compared the reproductive environments and phenotypes of early and late season breeding stocks of chum salmon, Oncorhynchus keta, to test the hypothesis that seasonal separation has resulted in phenotypically distinct forms. These were autumn- and winter-spawning populations from Bush Creek (Vancouver Island, B.C.) and a winter-spawning stock from nearby Walker Creek. All stocks had a similar time of downstream migration of the fry. No differences were found among the Walker Creek and the autumn-spawning stock of Bush Creek in age at maturity, length composition of spawners, egg size, vertebral counts of adults and fry, and time of fry migration. The winter-spawning stock of Bush Creek differed from the other stocks in egg size and vertebral counts. Discriminant analysis of 10 morphological features of the fry revealed considerable overlap in body form among the stocks. These results do not support the hypothesis that distinct life history morphs are associated with the season of reproduction. We propose that the large amount of similarity in terms of morphology and seasonality among the populations may be the product of selection. Genetic divergence may have occurred to compensate for the environmental differences experienced during embryonic development.

The effect of spawning time and incubation temperature on meristic variation in chum salmon (Oncorhynchus keta)

1986 ◽  
Vol 64 (1) ◽  
pp. 45-48 ◽  
Author(s):  
T. D. Beacham ◽  
C. B. Murray
Keyword(s):  
Chum Salmon ◽  
Incubation Temperature ◽  
Oncorhynchus Keta ◽  
Gill Rakers ◽  
Dorsal Fin ◽  
Chum Salmon Oncorhynchus Keta ◽  
Fin Rays ◽  
Spawning Stock ◽  
Spawning Time ◽  
Pelvic Fin

Variability in the number of dorsal, anal, caudal, pectoral, and pelvic fin rays, vertebrae, and gill rakers of early and late spawning stocks of Chehalis River chum salmon (Oncorhynchus keta) incubated under controlled water temperatures of 4, 8, and 12 °C was examined. The early spawning stock had fewer dorsal fin rays, more anal fin rays, fewer pectoral and pelvic fin rays, and fewer gill rakers than did the late spawning stock. Chum salmon originally incubated at 4 °C had the lowest number of dorsal fin rays, but the highest number of vertebrae and gill rakers. Chum salmon originally incubated at 8 °C had the highest number of anal fin rays, and those incubated at 12 °C had the highest number of pectoral fin rays. Meristic phenotypes had both a genetic and an environmental component.

Effect of egg size on incubation time and alevin and fry size in chum salmon (Oncorhynchus keta) and coho salmon (Oncorhynchus kisutch)

1985 ◽  
Vol 63 (4) ◽  
pp. 847-850 ◽  
Author(s):  
T. D. Beacham ◽  
F. C. Withler ◽  
R. B. Morley
Keyword(s):  
Egg Size ◽  
Chum Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Oncorhynchus Keta ◽  
Free Swimming ◽  
Chum Salmon Oncorhynchus Keta ◽  
Hatching Time ◽  
Significant Difference ◽  
Yolk Absorption

Variability in hatching time, time of exogenous yolk absorption ("button up") of alevins, alevin size, and fry size was investigated with respect to initial egg size for chum salmon (Oncorhynchus keta) and coho salmon (Oncorhynchus kisutch). There was no significant difference with respect to egg size in hatching time of the alevins (stage between hatching and emergence from the redd) or time of exogenous yolk absorption for either species. For both species, alevins hatching from large eggs were longer and had greater amounts of yolk than those hatching from small eggs. Tissue weights of the alevins were not different. The differences in size between these two groups of alevins were maintained throughout the alevin stage and were greater at exogenous yolk absorption than at hatching. Fry (newly emerged, free-swimming young) derived from large eggs had greater tissue weight at exogenous yolk absorption than those derived from small eggs.

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.

Sign in / Sign up

Export Citation Format

Share Document