Female Size and Nest Depth in Coho Salmon (Oncorhynchus kisutch)

1984 ◽  
Vol 41 (1) ◽  
pp. 204-206 ◽  
Author(s):  
Eric P. van den Berghe ◽  
Mart R. Gross
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Female Size ◽  
Strongly Correlated ◽  
Nest Sites ◽  
Nest Depth ◽  
Different Depths

Nest depth was strongly correlated with female size in coho salmon (Oncorhynchus kisutch). Since nests of different-sized females are at different depths, they are differentially vulnerable to destruction by floods and to other females competing for the same nest sites.

Importance of Smolt Size and Early Ocean Growth to Interannual Variability in Marine Survival of Coho Salmon (Oncorhynchus kisutch)

1990 ◽  
Vol 47 (11) ◽  
pp. 2181-2194 ◽  
Author(s):  
L. Blair Holtby ◽  
Bruce C. Andersen ◽  
Ronald K. Kadowaki
Keyword(s):  
Interannual Variability ◽  
Coho Salmon ◽  
Age Groups ◽  
Oncorhynchus Kisutch ◽  
Northwest Coast ◽  
Size Distributions ◽  
Strongly Correlated ◽  
Large Size ◽  
Ocean Conditions ◽  
Marine Survival

The importance of smolt size and early ocean growth to the marine survival of coho salmon was examined over a 17-yr period at Carnation Creek, British Columbia. Comparisons of overall marine survival were made both between-years, using two smolt age-groups of different mean sizes, and within-years using observed smolt size distributions and smolt size distributions back-calculated from the scales of returning adults. Large size did not confer a consistent survival advantage but large smolts did survive better in years when marine survival was relatively poor. Marine survivals were strongly correlated with early ocean growth as estimated by the spacing of the first five ocean circuli on the scales of returning adults. Marine survival and early ocean growth were positively correlated with ocean conditions indicative of strong upwelling along the northwest coast of Vancouver Island. Neither smolt survival nor early ocean growth were correlated with regional coho smolt production. Our observations suggest that interannual variability in smolt survival was being driven by ocean conditions that determined smolt growth rates which subsequently affected the susceptibility of smolts to a size-selective predator.

Selection for Adult Size in Female Coho Salmon (Oncorhynchus kisutch)

1986 ◽  
Vol 43 (10) ◽  
pp. 1946-1959 ◽  
Author(s):  
L B. Holtby ◽  
M. C. Healey
Keyword(s):  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Selective Advantage ◽  
Evolutionary Stable Strategy ◽  
Relative Fitness ◽  
Female Size ◽  
Adult Size ◽  
Stable Strategy ◽  
Wide Range

Several recent studies have presented evidence that large size confers a selective advantage to female Pacific salmon. Nevertheless, a wide range of female sizes is normally present in any spawning population. Two possible explanations exist for the observed range in female size. First, average female size might be determined by an optimizing process with variation around the optimum size due to individual differences in success at obtaining food. Second, various sizes of females might coexist as a mixed evolutionary stable strategy. Under the first explanation, females of sizes other than the optimum would display lower fitness whereas, under the second explanation, females of all sizes would be equally fit. We investigated factors affecting survival of eggs, fry, and smolts of coho salmon (Oncorhynchus kisutch) in Carnation Creek on Vancouver Island with a view to determining the relative fitness of different sized females. Egg-to-fry mortality was best explained by a model that included only the effects of stream bed scour and gravel quality. Including an effect of female size, expressed through depth of egg burying, worsened the model's predictive capability. We could find no evidence that the eggs of large females consistently survived better during incubation than those of small females. In fact, we observed three instances in which it appeared that the eggs of small females survived better. In Carnation Creek, large 1- and 2-yr-old smolts did not consistently survive better in the marine environment than small smolts. Thus, we were unable to demonstrate that the reproductive success of large females was consistently higher than that of small females, contrary to the hypothesis that female size is the result of an optimizing process. In Carnation Creek the observed range of female sizes probably represents an evolutionary stable strategy in which all sizes have equal fitness. We propose a model that predicts female size and variance in size based on the conflicting selective effects of gravel quality, scour, and competition for nest sites.

Induced ovulation in coho salmon (Oncorhynchus kisutch). I. Further studies on the use of salmon pituitary preparations

Aquaculture ◽  
1981 ◽  
Vol 26 (1-2) ◽  
pp. 117-127 ◽  
Author(s):  
George A. Hunter ◽  
Edward M. Donaldson ◽  
Helen M. Dye
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Induced Ovulation

Physiological Response of Juvenile Coho Salmon (Oncorhynchus kisutch) and Rainbow Trout (Salmo gairdneri) to Handling and Crowding Stress in Intensive Fish Culture

1976 ◽  
Vol 33 (12) ◽  
pp. 2699-2702 ◽  
Author(s):  
Gary A. Wedemeyer
Keyword(s):  
Rainbow Trout ◽  
Feeding Behavior ◽  
Coho Salmon ◽  
Physiological Stress ◽  
Oncorhynchus Kisutch ◽  
Fish Distribution ◽  
Salmo Gairdneri ◽  
Crowding Stress ◽  
Normal Feeding ◽  
Intensive Fish Culture

Moving 4–5-in. coho salmon (Oncorhynchus kisutch) held in soft (20 ppm CaCO3) water from the relatively light loading density of 0.5 lb/ft3 to 1, 2, or 4 lb/ft3 (density index, DI = 0.1, 0.2, 0.4, 0.8) caused significant stress as indicated by loss of feeding behavior, but only minimal physiological disturbances, as indicated by lack of hyperglycemia or hypochloremia. However, moving them to 6 or 12 lb/ft3 (DI = 1.2, 2.4) caused significant physiological stress which required at least a week for recovery. Smolting coho salmon were physiologically stressed by population densities of 1 lb/ft3 or more and a subclinical corynebacterial kidney infection was activated. Rainbow trout (Salmo gairdneri) (4–5 in.) were physiologically stressed when moved and held at 1 lb/ft3 or more but retained normal feeding behavior. This indicates that handling and crowding stress will be minimized in softwater areas if densities in fish distribution trucks or in ponds or raceways during disease treatments are held to 0.1–0.5 lb/gal.

scholarly journals Hyperbilirubinemia of Coho Salmon Oncorhynchus kisutch Infected with Erythrocytic Inclusion Body Syndrome (EIBS) Virus

1994 ◽  
Vol 60 (5) ◽  
pp. 519-521 ◽  
Author(s):  
Tadashi Sakai ◽  
Hisashi Murata ◽  
Kiyoshi Yamauchi ◽  
Kiyotaka Takahashi ◽  
Nobuaki Okamoto ◽  
...  
Keyword(s):  
Inclusion Body ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch
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