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.

Effect of varying temperature regimes on the development of pink salmon (Oncorhynchus gorbuscha) eggs and alevins

1986 ◽  
Vol 64 (3) ◽  
pp. 670-676 ◽  
Author(s):  
Clyde B. Murray ◽  
Terry D. Beacham
Keyword(s):  
Developmental Stages ◽  
Incubation Temperature ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Egg Survival ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Temperature Changes ◽  
Temperature Regimes ◽  
Rapid Temperature ◽  
Development Temperature

Eggs and alevins from six odd-year, brood-line stocks of pink salmon (Oncorhynchus gorbuscha) spawning in southern British Columbia were incubated under varying temperature regimes and subjected to rapid temperature changes at specific developmental stages. Increasing or decreasing temperature regimes had no significant effect on egg and alevin survival. The inclusion of 2 or 4 °C in the temperature regime reduced egg survival. Rapid temperature changes from 12 to 1 °C late in development reduced alevin survival when compared with transfers from 8 to 1 °C. Hatching and emergence time varied inversely with mean incubation temperature. Decreasing temperature regimes produced longer and heavier alevins and fry than increasing temperature regimes. Low mean incubation temperatures from fertilization to fry emergence resulted in longer and heavier alevins and fry than those at higher mean temperature. Transfers from 8 or 12 °C to 1 °C early in development had a greater effect on alevin length and weight than transfers late in development. Temperature regimes can be manipulated to enhance survival, control development time, and increase alevin and fry size.

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.

Supplementary Checks on the Scales of Pink Salmon (Oncorhynchus gorbuscha) and Chum Salmon (O. keta)

1965 ◽  
Vol 22 (6) ◽  
pp. 1477-1489 ◽  
Author(s):  
H. T. Bilton ◽  
W. E. Ricker
Keyword(s):  
British Columbia ◽  
Chum Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Commercial Fisheries ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Clear Cut ◽  
Second Year Of Life ◽  
Second Year ◽  
Similar Incidence

Among 159 central British Columbia pink salmon that had been marked by removal of two fins as fry and had been recovered in commercial fisheries after one winter in the sea, the scales of about one-third showed a supplementary or "false" check near the centre of the scale, in addition to the single clear-cut annulus. This evidence from fish of known age confirms the prevailing opinion that such extra checks do not represent annuli, hence that the fish bearing them are in their second year of life rather than their third. Unmarked pink salmon from the same area, and some from southern British Columbia, had a generally similar incidence of supplementary checks. In both marked and unmarked fish the supplementary checks varied in distinctness from faint to quite clear. In a sample of scales of 14 double-fin marked chum salmon which were known to be in their 4th year, all fish had the expected 3 annuli, and 12 fish had a supplementary check inside the first annulus.

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