Influence of the Abundance, Size, and Yolk Reserves of Juvenile Chum Salmon (Oncorhynchus keta) on Predation by Freshwater Fishes in a Small Coastal Stream

1987 ◽  
Vol 44 (2) ◽  
pp. 236-243 ◽  
Author(s):  
Kurt L. Fresh ◽  
Steven L. Schroder
Keyword(s):  
Chum Salmon ◽  
Coho Salmon ◽  
Salmo Gairdneri ◽  
Oncorhynchus Keta ◽  
Predator Prey ◽  
Chum Salmon Oncorhynchus Keta ◽  
Salmon Fry ◽  
Juvenile Chum Salmon ◽  
Controlled Flow ◽  
The Relationship

Predator–prey interactions between juvenile chum salmon (Oncorhynchus keta) and piscivores were studied in a small coastal stream and in sections of a controlled-flow channel. The predators were primarily large [Formula: see text] rainbow trout (Salmo gairdneri) and large [Formula: see text] coho salmon (O. kisutch). The relationship between chum salmon fry abundance and the quantity consumed by predators suggested a type II functional response. Neither prey size nor prey abundance influenced predation, but predators did select fry with relatively high yolk reserves. Our results suggest that the numbers of juvenile chum salmon needed to satiate predators and to enhance fry survival are attainable by enhancement projects located on smaller rivers and streams.

On the structure and enzymatic degradation of the external membrane of the salmon egg

1969 ◽  
Vol 47 (1) ◽  
pp. 146-148 ◽  
Author(s):  
Gordon R. Bell ◽  
Gary E. Hoskins ◽  
John W. Bagshaw
Keyword(s):  
Metal Ions ◽  
Enzymatic Degradation ◽  
Chum Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Oncorhynchus Keta ◽  
Hatching Enzyme ◽  
Chum Salmon Oncorhynchus Keta ◽  
Optimum Ph

The radiate membrane ("capsule") of chum salmon (Oncorhynchus keta) eggs has integrated with it another, outermost, non-chitinous membrane which prevents the digestion of the radiate membrane by "hatching enzyme" of chum salmon or by pronase applied externally but not internally. Crude chum salmon hatching enzyme(s) has an optimum pH of 7.5–8.0 for the release of soluble peptides from the radiate membrane, requires metal ions for activity, and can also decompose the radiate membranes of coho salmon (Oncorhynchus kisutch) and steelhead (Salmo gairdneri) eggs.

Ceratomyxa shasta (Myxosporida) Disease in Chum Salmon (Oncorhynchus keta) in British Columbia

1975 ◽  
Vol 32 (9) ◽  
pp. 1640-1643 ◽  
Author(s):  
L. Margolis ◽  
T. P. T. Evelyn
Keyword(s):  
British Columbia ◽  
Chum Salmon ◽  
Coho Salmon ◽  
Host Record ◽  
Oncorhynchus Keta ◽  
New Host ◽  
Chum Salmon Oncorhynchus Keta ◽  
New Host Record ◽  
Natural Range ◽  
Juvenile Chum Salmon

Infections with the myxosporidan Ceratomyxa shasta Noble, 1950 were confirmed in four juvenile chum salmon (Oncorhynchus keta) caught at sea near Nanaimo in 1965 and 1968. These cases represent a new host record for C. shasta and a northward extension of the parasite’s known natural range. Ceratomyxosis was also presumptively diagnosed in a coho salmon (Oncorhynchus kisutch) in British Columbia.

Influence of Size Upon the Adaptation of Steelhead Trout (Salmo gairdneri) and Chum Salmon (Oncorhynchus keta) to Sea Water

1961 ◽  
Vol 18 (3) ◽  
pp. 401-415 ◽  
Author(s):  
Arthur H. Houston
Keyword(s):  
Chum Salmon ◽  
Sea Water ◽  
Water Salinity ◽  
Salmo Gairdneri ◽  
Oncorhynchus Keta ◽  
Electrolyte Balance ◽  
Steelhead Trout ◽  
Chum Salmon Oncorhynchus Keta ◽  
Salmonid Species ◽  
Juvenile Chum Salmon

Steelhead trout in the smolt phase of development adapted to sea water (salinity 22–24 parts per thousand) more rapidly and with less extensive departures from regulated conditions of water–electrolyte balance than did the larger post-smolts. By contrast, the extent and duration of the corresponding changes accompanying adaptation of juvenile chum salmon to sea water varied inversely with size. The data are discussed in relation to the distinction between smolting and non-smolting salmonid species.

Detritus and Juvenile Salmon Production in the Nanaimo Estuary: II. Meiofauna Available as Food to Juvenile Chum Salmon (Oncorhynchus keta)

1979 ◽  
Vol 36 (5) ◽  
pp. 497-503 ◽  
Author(s):  
J. R. Sibert
Keyword(s):  
Chum Salmon ◽  
Late Summer ◽  
Oncorhynchus Keta ◽  
Close Coupling ◽  
Chum Salmon Oncorhynchus Keta ◽  
Salmon Fry ◽  
Harpacticoid Copepods ◽  
Food Requirement ◽  
Juvenile Chum Salmon

The meiofauna of the Nanaimo Estuary are briefly described. Nematodes and harpacticoid copepods were the numerically dominant taxa and reached their maximum population densities in late summer. Harpacticus uniremis was very important to the early diet of juvenile chum salmon (Oncorhynchus keta) but was one of the least common harpacticoid copepods in the estuary. The productivity of H. uniremis was found to be only slightly greater than the calculated food requirement of the chum salmon fry; there was close coupling between prey and predator. The role of detritus and bacterially processed carbon in the feeding of H. uniremis are discussed. Key words: harpacticoid copepods, secondary production, detritus, Harpacticus uniremis, turnover ratios, meiofauna

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.

Spawning Behavior of Chum Salmon (Oncorhynchus keta) and Rainbow Trout (Salmo gairdneri)

1975 ◽  
Vol 32 (5) ◽  
pp. 633-642 ◽  
Author(s):  
A. F. Tautz ◽  
C. Groot
Keyword(s):  
Rainbow Trout ◽  
Chum Salmon ◽  
Nest Site ◽  
Salmo Gairdneri ◽  
Oncorhynchus Keta ◽  
Spawning Behavior ◽  
Current Pattern ◽  
Chum Salmon Oncorhynchus Keta ◽  
Nest Sites ◽  
Gravel Size

Detailed accounts of the spawning behavior of chum salmon (Oncorhynchus keta) and rainbow trout (Salmo gairdneri) in laboratory flumes are provided. The behavioral activities, quivering, probing, and crossing over increase in frequency as a function of time prior to spawning whereas digging remains constant or decreases slightly. Maps of digging locations and movie films suggest nest shape and current pattern are monitored by the female, allowing her to intensify her digging activity near the center of the nest. Probing appears to be a signal to the male indicating approach of oviposition and also provides information to the female regarding the shape and suitability of the nest site. The probing act is also used in the synchronization of the male and female spawning acts. Changes in velocity do not appear to markedly affect nest construction either in terms of number of digs to oviposition or in size of nest constructed. It is inferred that velocity and gravel size are important insofar as they influence the construction of a suitable nest depression. Nest sites would appear to be selected on the basis of acceleration of flow rather than velocity per se though high limits must obviously exist.

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