Two Generations of Hybrids between Even- and Odd-Year Pink Salmon (Oncorhynchus gorbuscha): A Test for Outbreeding Depression?

1991 ◽  
Vol 48 (9) ◽  
pp. 1744-1749 ◽  
Author(s):  
A. J. Gharrett ◽  
W. W. Smoker
Keyword(s):  
Genetic Variation ◽  
First Generation ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Outbreeding Depression ◽  
Gill Rakers ◽  
Bilateral Asymmetry ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Two Generations

Hybrids of genetically isolated odd- and even-year pink salmon (Oncorhynchus gorbuscha) from the same stream were made by fertilizing eggs with cryopreserved milt. Anadromous first-generation (F1) hybrids and controls returned to the hatchery at equal rates (153 of 5483 and 160 of 5492, respectively), on the same average date, and with the same size. However, variances of F1 size (female length and weight and male length) exceeded variances of control sizes, suggesting increased genetic variation in F1's. Only 11 of 5165 F2's returned. F2's were similar meristically and in size to fish of their parents' generation, but were bilaterally more asymmetric in number of gill rakers and in combined numbers of gill rakers and of branchiostegals. Increased F1 variation followed by low F2 returns and increased bilateral asymmetry is a pattern to be expected when coadapted allele complexes are disrupted by outbreeding depression.

Genetic variation in body weight of pink salmon (Oncorhynchus gorbuscha)

Genome ◽  
1989 ◽  
Vol 32 (2) ◽  
pp. 227-231
Author(s):  
Terry D. Beacham
Keyword(s):  
Body Weight ◽  
Genetic Variation ◽  
Maternal Effects ◽  
Egg Quality ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
In Captivity ◽  
Factorial Mating ◽  
Factorial Mating Design

A factorial mating design was used in which three males were mated to either two or three females in each of the three sets of pink salmon (Oncorhynchus gorbuscha), and the juveniles were reared for 420 days after fry emergence. The parents used were derived from pink salmon that had been reared for one generation in captivity. Pink salmon families from this captive second generation were characterized by low growth rates, high within-family variance in juvenile weight, and low (< 0.11) heritability of juvenile weight. Maternal effects were estimated to account for about 20% of the observed variation in juvenile weight after the juveniles had been reared for 420 days. The observed results were postulated to be accounted for by variation in egg quality in the parental generation, presumably a consequence of an inadequate diet.Key words: development, genetics, growth, pink salmon, size.

Counts of Gill Rakers and Pyloric Caeca in Pink Salmon

1945 ◽  
Vol 6d (5) ◽  
pp. 392-398
Author(s):  
A. L. Pritchard
Keyword(s):  
British Columbia ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Gill Rakers ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Pyloric Caeca ◽  
Breeding Group

Counts of gill rakers and pyloric caeca on pink salmon (Oncorhynchus gorbuscha) from different rivers in British Columbia overlap in range to such an extent that it would be impossible with any degree of accuracy to assign isolated individuals from an ocean population to a distinct "breeding group" on the basis of these characters. While the comparison of the averages of each character demonstrates significant differences between separate rivers in the same year in some cases, in others no such difference is noticeable. The averages for the characters do not consistently show differences between populations of two succeeding years which are known to be distinct, e.g. those of 1940 and 1941.

Influence of photoperiod on the timing of reproductive maturation in pink salmon (Oncorhynchus gorbuscha) and its application to genetic transfers between odd- and even-year spawning populations

1994 ◽  
Vol 72 (5) ◽  
pp. 826-833 ◽  
Author(s):  
Terry D. Beacham ◽  
Clyde B. Murray ◽  
L. Walter Barner
Keyword(s):  
First Generation ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Captive Population ◽  
Wild Populations ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Photoperiod Regime ◽  
Spawning Time ◽  
Time Of Year ◽  
Development Temperature

Pink salmon (Oncorhynchus gorbuscha) embryos were obtained in April 1991 from the first generation of a 1989 brood line, which had been induced to spawn 6 months earlier than wild populations, which spawn in October. These embryos and subsequent juveniles were reared at a development temperature and under a photoperiod regime that induced some fish from this second generation to mature in October 1992, the correct time of year for spawning of wild populations. Other captive groups of pink salmon also matured in April 1993, permitting a comparison of fecundity, egg fertility, and egg size among female spawners in different photoperiods. Although the wild population spawns only in odd years, the captive population, originally derived from odd-year spawners, has been manipulated to spawn in even years. This shifting of the spawning time of the captive population may permit a transplant of odd-year genes into an even-year line, perhaps allowing the development of a run of even-year pink salmon in the Fraser River, British Columbia.

Quantitative genetic variation and genotype by environment interaction of embryo development rate in pink salmon (Oncorhynchus gorbuscha)

1998 ◽  
Vol 55 (9) ◽  
pp. 2048-2057 ◽  
Author(s):  
K P Hebert ◽  
P L Goddard ◽  
W W Smoker ◽  
A J Gharrett
Keyword(s):  
Genetic Variation ◽  
Pink Salmon ◽  
Genotype By Environment Interaction ◽  
Development Rate ◽  
Oncorhynchus Gorbuscha ◽  
Environment Interaction ◽  
Paternal Effects ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Genotype By Environment ◽  
Quantitative Genetic

Quantitative genetic variation of development rate was evident among 20 half-sib and 40 full-sib families within each of two seasonally separate components of a population of pink salmon (Oncorhynchus gorbuscha) (Ho: no sire effect on temperature units at hatch, P < 0.02). Differences between averages of families spawned 3 weeks apart may have had genetic or environmental sources (e.g., in constant 8°C, early embryos hatched at 606 temperature units, and late embryos, at 625). Statistical interactions between paternal effects and environment (embryos were cultured in four temperature regimes, two simulated natural regimes and two constant temperatures; Ho: no sire by regime interaction effect on temperature units at hatch, P < 0.09) were weak evidence that genotype by environment interactions contributed to variation. Paternal effects in analysis of variance (evidence of additive genetic variation) were detected only at later stages. Evidences of genetic variation and of interactions between genotypes and environments are pertinent to resource conservation because they suggest that harvest management or hatchery practice have the potential to reduce genetic variation in salmon populations.

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