Aspects of the Winter Ecology of Juvenile Coho Salmon (Oncorhynchus kisutch) and Steelhead Trout (Salmo gairdneri)

1975 ◽  
Vol 32 (5) ◽  
pp. 667-680 ◽  
Author(s):  
David R. Bustard ◽  
David W. Narver
Keyword(s):  
Water Temperature ◽  
Coho Salmon ◽  
Age Groups ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Tree Roots ◽  
Beaver Ponds ◽  
Stream System ◽  
Overwintering Area

The major physical characteristics of overwintering areas for juvenile coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdneri) are described for a small, unlogged, west coast Vancouver Island stream. During the winter months age I+ coho and steelhead were found at a range of depths mainly greater than 45 cm and in deeper water than age 0 of either species. About 45% of age 0 steelhead observed were in water < 15 cm deep. The depth occupied by coho and age I+ steelhead was negatively correlated with water temperature below 8.5 C. Coho were associated less closely with the bottom than were steelhead. At 7 C or less most fish were associated with water velocities of < 15 cm/s. Velocities in which steelhead occurred were positively correlated with rising temperature above 4 C. As water temperature decreased from 9 to 2 C, coho and steelhead moved closer to cover. Cover used by coho and age I+ steelhead most frequently was logs and upturned tree roots, although debris accumulations and overhanging banks were also used. Both age-groups of coho used overhanging brush but steelhead did not. Over 50% of age 0 steelhead were associated with rocks 10–25 cm in diameter. Sidepools and quiet back channels that contained water only in the winter and that had combinations of the above cover types were populated by coho during the winter. A series of unused beaver ponds, dry in the summer, was an important overwintering area for coho with a survival rate about twice as high as the 35% estimated for the entire stream system.

Relation of Water Temperature to Flexibacter columnaris Infection in Steelhead Trout (Salmo gairdneri), Coho (Oncorhynchus kisutch) and Chinook (O. tshawytscha) Salmon

1975 ◽  
Vol 32 (9) ◽  
pp. 1553-1559 ◽  
Author(s):  
R. A. Holt ◽  
J. E. Sanders ◽  
J. L. Zinn ◽  
J. L. Fryer ◽  
K. S. Pilcher
Keyword(s):  
Water Temperature ◽  
Experimental Infection ◽  
Chinook Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Disease Process ◽  
Salmo Gairdneri ◽  
Contact Method ◽  
Steelhead Trout ◽  
Time To Death

The effect of water temperature upon mortality from experimental infection by Flexibacter columnaris and on mean time to death was investigated in juvenile steelhead trout (Salmo gairdneri), coho salmon (Oncorhynchus kisutch), and spring chinook salmon (Oncorhynchus tshawytscha). Eight temperatures increasing from 3.9 to 23.3 C (39 to 74 F) by increments of 2.8 C (5 F) were studied. Fish were infected by the direct contact method whereby a suspension of the pathogen was added to the water. It was found that at temperatures of 9.4 C (49 F) and below, no deaths due to the experimental infection with F. columnaris occurred. At 12.2 C (54 F) mortality varied from 4 to 20% among the three species, and increased progressively with increasing temperature to 100% in steelhead trout and coho salmon at 20.5 C (69 F), and 70% in chinook salmon at that temperature. With all three salmonid species, an inverse linear relationship was found between water temperature and the log10 of the mean number of days from exposure to death. This means that as the temperature increased above 12.2 C (54 F), the disease process was progressively accelerated, resulting in a minimum time to death at 20.5 or 23.3 C (69 or 74 F) and a maximum at 12.2 C (54 F). The results indicate that under the conditions of these experiments, columnaris disease in salmonids was completely suppressed by water temperatures of 9.4 C (49 F) or below.

Relation of Water Temperature to Infections of Coho Salmon (Oncorhynchus kisutch), Chinook Salmon (O. tshawytscha), and Steelhead Trout (Salmo gairdneri) with Aeromonas salmonicida and A. hydrophila

1978 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
W. J. Groberg Jr. ◽  
R. H. McCoy ◽  
K. S. Pilcher ◽  
J. L. Fryer
Keyword(s):  
Water Temperature ◽  
Chinook Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Infected Fish ◽  
Aeromonas Salmonicida ◽  
Salmo Gairdneri ◽  
Steelhead Trout

Juvenile steelhead trout (Salmo gairdneri), coho salmon (Oncorhynchus kisutch), and spring chinook salmon (O. tshawytscha) were infected by intraperitoneal or intramuscular injection with Aeromonas salmonicida or A. hydrophila at seven temperatures from 3.9 to 20.5 °C. At 3.9 and 6.7 °C, mortality in fish infected with A. salmonicida varied from 2 to 26% among the three salmonid species. At 20.5 °C 93–100% of these animals died within 2 or 3 days; at 6.7 °C or lower the fish survived for 12–23 days. Growth of A. salmonicida in vitro was influenced by temperature in a manner very similar to its influence on the in vivo infection. Comparable experiments with A. hydrophila gave results much like those with A. salmonicida, though some differences were noted. At a temperature of 20.5 °C percent mortality ranged from 64 to 100%. At 9.4 °C or below no deaths attributed to A. hydrophila occurred. Fatally infected fish died more rapidly at the higher temperatures. Key words: Aeromonas salmonicida, A. hydrophila, water temperature, furunculosis, motile aeromonas septicemia, coho salmon, chinook salmon, steelhead trout

Relation of Water Temperature to Ceratomyxosis in Rainbow Trout (Salmo gairdneri) and Coho Salmon (Oncorhynchus kisutch)

1975 ◽  
Vol 32 (9) ◽  
pp. 1545-1551 ◽  
Author(s):  
L. R. Udey ◽  
J. L. Fryer ◽  
K. S. Pilcher
Keyword(s):  
Rainbow Trout ◽  
Water Temperature ◽  
Coho Salmon ◽  
Geometric Mean ◽  
Oncorhynchus Kisutch ◽  
Experimental Period ◽  
Salmo Gairdneri ◽  
Percent Mortality ◽  
Temperature Levels ◽  
Mean Time

Juvenile rainbow trout (Salmo gairdneri) were exposed to infection with Ceratomyxa shasta transferred in groups of 25 to aquaria, and tempered to various temperature levels increasing from 3.9 to 23.3 C (39 to 74 F) by 2.8 degree C (5 degree F) increments. During a 237-day observation period mortality in the experimental groups averaged about 80%, and was independent of water temperature between 6.3 and 23.3 C (44 and 74 F). No deaths occurred at 3.9 C (39 F). The geometric-mean time from exposure to death, however, was definitely a function of temperature, increasing from 14 days at 23.3 C (74 F) to 155 days at 6.7 C (44 F).A similar experiment with juvenile coho salmon (Oncorhynchus kisutch) gave quite different results. In this species, percent mortality due to C. shasta increased progressively from 2% at 9.4 C (49 F) to 22% at 15.0 C (59 F) and 84% at 20.5 C (69 F). No deaths occurred at 3.9 or 6.7 C (39 or 44 F) during the 201-day experimental period. As with the rainbow trout, the geometric-mean time from exposure to death was temperature dependent, increasing from 12.5 days at 23.3 C (74 F) to 146 days at 9.4 C (49 F). The data indicate that ceratomyxosis in coho can be suppressed by water temperatures of 6.7 C (44 F) or below.

Some Physiological Aspects of Sublethal Heat Stress in the Juvenile Steelhead Trout (Salmo gairdneri) and Coho Salmon (Oncorhynchus kisutch)

1973 ◽  
Vol 30 (6) ◽  
pp. 831-834 ◽  
Author(s):  
Gary Wedemeyer
Keyword(s):  
Heat Stress ◽  
Vitamin C ◽  
Blood Sugar ◽  
Temperature Increase ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Acid Base ◽  
Acid Base Equilibrium

A rapid (3 min) but sublethal temperature increase from 10 to 20 imposed a greater stress on juvenile coho salmon (Oncorhynchus kisutch) than on juvenile steelhead trout (Salmo gairdneri). Both species suffered hyperglycemia, hypocholesterolemia, increased blood hemoglobin, and decreased blood sugar regulatory precision, but the steelhead recovered more quickly. Acid–base equilibrium was essentially unaffected, and only the coho suffered any significant interrenal vitamin C depletion. Vitamin C normalization required about 24 hr.

Relation of Water Temperature to Bacterial Kidney Disease in Coho Salmon (Oncorhynchus kisutch), Sockeye Salmon (O. nerka), and Steelhead Trout (Salmo gairdneri)

1978 ◽  
Vol 35 (1) ◽  
pp. 8-11 ◽  
Author(s):  
J. E. Sanders ◽  
K. S. Pilcher ◽  
J. L. Fryer
Keyword(s):  
Kidney Disease ◽  
Sockeye Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Causative Organism ◽  
Steelhead Trout ◽  
Bacterial Kidney Disease ◽  
Percent Mortality ◽  
Disease Agent

Juvenile coho salmon (Oncorhynchus kisutch), sockeye salmon (O. nerka), and steelhead trout (Salmo gairdneri) were infected by intraperitoneal injection of a suspension of the causative organism of bacterial kidney disease at seven experimental temperatures from 3.9 to 20.5 °C. In coho salmon and steelhead trout percent mortality was maximal (78–100%) in the range of 6.7–12.2 °C. As the temperature increased above 12.2 °C mortality declined progressively; at 20.5 °C it was only 8–14%. The two highest temperatures had some suppressing effect on the disease, which was greatest at 20.5 °C. In sockeye salmon this was not apparent, as percent mortality was essentially 100% at all temperatures from 6.7 to 20.5 °C; this species appeared to be highly susceptible to the disease agent. Temperature also influenced the mean number of days between infection and death. This interval was shortest in all three species of salmonids at the higher temperatures, varying from 21 to 34 days at 15.0–20.5 °C. It increased progressively as temperature decreased below this range; at 6.7 °C it varied from 60 to 71 days among the three species. Key words: bacterial kidney disease, temperature, salmonids, Corynebacterium, coho salmon, sockeye salmon, steelhead trout

Sustained Exercise Increases Plasma Growth Hormone Concentrations in Two Anadromous Salmonids

1988 ◽  
Vol 45 (4) ◽  
pp. 747-749 ◽  
Author(s):  
Bruce A. Barrett ◽  
Brian A. McKeown
Keyword(s):  
Growth Hormone ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Steady Increase ◽  
Steelhead Trout ◽  
Plasma Growth Hormone ◽  
Plasma Gh

Sustained exercise for 24 h at 1.5 body lengths per second (bl/s) resulted in a severalfold increase in the plasma growth hormone (GH) concentration of steelhead trout (Salmo gairdneri) and coho salmon (Oncorhynchus kisutch). Peak levels occurred 10 min postexercise and returned to basal levels within 4 h of exercise termination. GH levels exhibited a steady increase after the fourth hour of exercise and peaked at 24 h. Individuals exercised for 48 h did not exceed plasma GH levels of the 24-h peak.

Changes in Gill Adenosinetriphosphatase Activity Associated with Parr–Smolt Transformation in Steelhead Trout, Coho, and Spring Chinook Salmon

1972 ◽  
Vol 29 (2) ◽  
pp. 167-171 ◽  
Author(s):  
W. S. Zaugg ◽  
L. R. McLain
Keyword(s):  
Atpase Activity ◽  
Chinook Salmon ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Similar Increase ◽  
Activity Increase ◽  
Fish Hatchery ◽  
Transport Atpase

The average Na+- and K+-stimulated adenosinetriphosphatase (ATPase) activity of microsomes from gills of hatchery-reared coho salmon (Oncorhynchus kisutch) increased from about 12 μmoles ATP hydrolyzed/mg protein per hr during February through mid-April to approximately 24 in mid-May. Larger fish developed higher activities than smaller fish. Hatchery-reared spring chinook salmon (O. tshawytscha) exhibited a similar increase 2–3 weeks earlier.In 2-year-old hatchery-reared steelhead trout (Salmo gairdneri), Na+-, K+-ATPase activities were elevated in some, but not all, smolt-appearing animals. Parr-appearing fish, including maturing males, showed no activity increase. When held in fresh water to July, steelhead smolts lost their silvery color and became more parr-like in appearance, and the previously elevated ATPase activity decreased to near pre-smolt levels. Yearling steelhead held at the laboratory showed a more consistent rise in ATPase activity.The increase in transport ATPase (Na+-, K+-stimulated) activity occurring during parr–smolt transformation is probably a preparatory step for saltwater adaption and may also be closely associated with migratory disposition.L'activité moyenne de l'adénosinetriphosphatase (ATPase) stimulée par Na+ et K+ dans les microsomes des branchies de saumons coho (Oncorhynchus kisutch) élevés en pisciculture augmente de 12 μmoles environ d'ATPase hydrolysée/mg de protéine par h de février à la mi-avril à 24 à la mi-mai. Les gros poissons développent une activité plus grande que les petits. Les saumons chinook de printemps (O. tshawytscha) élevés en pisciculture font preuve d'un accroissement semblable deux à trois semaines avant les saumons coho.

Role of Off-Channel Ponds in the Life Cycle of Coho Salmon (Oncorhynchus kisutch) and Other Juvenile Salmonids in the Coldwater River, British Columbia

1989 ◽  
Vol 46 (2) ◽  
pp. 232-242 ◽  
Author(s):  
S. Swales ◽  
C. D. Levings
Keyword(s):  
British Columbia ◽  
Oncorhynchus Tshawytscha ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
River Population ◽  
Main Species ◽  
Main River ◽  
Density And Biomass

Off-channel ponds in the upper reaches of the Coldwater River, British Columbia, were major rearing areas for juvenile coho salmon (Oncorhynchus kisutch). Chinook salmon (Oncorhynchus tshawytscha), steelhead trout (Salmo gairdneri), and Dolly Varden char (Salvelinus malma) were generally scarce in the ponds, although they were numerous in the main river. Coho salmon were predominant at "natural" river sites while steelhead trout was the main species at sites with "rip-rap" bank stabilization. Catches of juvenile coho were much lower in the main river than in the ponds where they were the main species, and were more variable in the river. Population density and biomass estimates of juvenile coho in the ponds ranged from 0.100 fish∙m−2 and 1.00 g∙m−2 to 1.00 fish∙m−2 and 5.15 g∙m−2, compared with density estimates of 0.08–0.23 fish∙m−2 in the river. The coho population in the ponds consisted of 0+ and 1+ age-groups in similar proportions, while in the main river the 0+ age-group was much more abundant. The growth rate of coho in the ponds was faster than in the main river, with pond fish reaching mean lengths of 62–79 mm at the end of the first growing season, compared with 53 mm in the main river. Smolt outmigration from the main study pond occurred in late spring with peak outmigration in May and June coinciding with peak river discharge and increasing water temperatures in the main river and pond.

Some Physiological Consequences of Handling Stress in the Juvenile Coho Salmon (Oncorhynchus kisutch) and Steelhead Trout (Salmo gairdneri)

1972 ◽  
Vol 29 (12) ◽  
pp. 1780-1783 ◽  
Author(s):  
Gary Wedemeyer
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Soft Water ◽  
Endocrine Function ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Handling Stress ◽  
Cholesterol Levels ◽  
Metabolic Dysfunctions ◽  
Tissue Chemistry

The stress of handling juvenile coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdneri) in soft water and in water with added salts was evaluated using blood and tissue chemistry fluctuations as indices of metabolic and endocrine function. Changes in plasma glucose, chloride, calcium, and cholesterol levels indicated that significant osmoregulatory and metabolic dysfunctions can occur and persist for about 24 hr after handling in soft water. Pituitary activation, as judged by lack of interrenal ascorbate depletion, did not occur. Increasing the ambient NaCl and Ca++ levels to about 100 milliosmols and 75–120 ppm, respectively, partially or completely alleviated the hyperglycemia and hypochloremia indicating that the stress of handling had been reduced.

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