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Reproductive success in wild and hatchery male coho salmon.

Neff BD, Garner SR, Fleming IA, Gross MR - R Soc Open Sci (2015)

Bottom Line: Salmon produced by hatcheries have lower fitness in the wild than naturally produced salmon, but the factors underlying this difference remain an active area of research.This paternity difference may result from inferior performance of hatchery males during sperm competition, female mate choice for wild males, or differential offspring survival.Regardless of its cause, the combination of inferior hierarchical position and inferior success at a position resulted in hatchery males having only half (51%) the reproductive success of wild males.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology , University of Western Ontario , London, Ontario, Canada N6A 5B7.

ABSTRACT
Salmon produced by hatcheries have lower fitness in the wild than naturally produced salmon, but the factors underlying this difference remain an active area of research. We used genetic parentage analysis of alevins produced by experimentally mixed groups of wild and hatchery coho salmon (Oncorhynchus kisutch) to quantify male paternity in spawning hierarchies. We identify factors influencing paternity and revise previously published behavioural estimates of reproductive success for wild and hatchery males. We observed a strong effect of hierarchy size and hierarchy position on paternity: in two-male hierarchies, the first male sired 63% (±29%; s.d.) of the alevins and the second male 37% (±29%); in three-male hierarchies, the first male sired 64% (±26%), the second male 24% (±20%) and the third male 12% (±10%). As previously documented, hatchery males hold inferior positions in spawning hierarchies, but we also discovered that hatchery males had only 55-84% the paternity of wild males when occupying the same position within a spawning hierarchy. This paternity difference may result from inferior performance of hatchery males during sperm competition, female mate choice for wild males, or differential offspring survival. Regardless of its cause, the combination of inferior hierarchical position and inferior success at a position resulted in hatchery males having only half (51%) the reproductive success of wild males.

No MeSH data available.


Paternity as a function of position in spawning hierarchies in coho salmon. The data (mean±s.d.) are plotted based on (a) total hierarchy size and (b) male origin.
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RSOS150161F1: Paternity as a function of position in spawning hierarchies in coho salmon. The data (mean±s.d.) are plotted based on (a) total hierarchy size and (b) male origin.

Mentions: The paternity analysis showed that the total size of a hierarchy (F2,38=23.70, p<0.001) and the position of a male within a hierarchy (F3,38=11.15, p<0.001) were the strongest predictors of paternity (figure 1a and table 2). In single-male hierarchies, the lone male sired all of the assigned alevins, although the presence of paternally unmatched alevins suggests that unobserved males could have sired up to a maximum of 3% of the alevins in those nests. In two-male hierarchies, the first male sired an average of 63% and the second male 37% of the alevins. In three-male hierarchies, the first male sired an average of 64% of the alevins, the second male 24% and the third male 12%. The addition of a third male thus had no effect on the paternity of the first male. Instead, the third male reduced the paternity of the second male by about 33% (=12%/36%). Across all hierarchy positions, hatchery males had lower paternity than wild males (F1,38=4.38, p=0.043; figure 1b). There was no significant effect of body mass on paternity in the model (i.e. once hierarchy size and position were accounted for: F1,38=2.07, p=0.16). Together, the variables included in the model explained 70% of the variance in paternity within male hierarchies.Figure 1.


Reproductive success in wild and hatchery male coho salmon.

Neff BD, Garner SR, Fleming IA, Gross MR - R Soc Open Sci (2015)

Paternity as a function of position in spawning hierarchies in coho salmon. The data (mean±s.d.) are plotted based on (a) total hierarchy size and (b) male origin.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555853&req=5

RSOS150161F1: Paternity as a function of position in spawning hierarchies in coho salmon. The data (mean±s.d.) are plotted based on (a) total hierarchy size and (b) male origin.
Mentions: The paternity analysis showed that the total size of a hierarchy (F2,38=23.70, p<0.001) and the position of a male within a hierarchy (F3,38=11.15, p<0.001) were the strongest predictors of paternity (figure 1a and table 2). In single-male hierarchies, the lone male sired all of the assigned alevins, although the presence of paternally unmatched alevins suggests that unobserved males could have sired up to a maximum of 3% of the alevins in those nests. In two-male hierarchies, the first male sired an average of 63% and the second male 37% of the alevins. In three-male hierarchies, the first male sired an average of 64% of the alevins, the second male 24% and the third male 12%. The addition of a third male thus had no effect on the paternity of the first male. Instead, the third male reduced the paternity of the second male by about 33% (=12%/36%). Across all hierarchy positions, hatchery males had lower paternity than wild males (F1,38=4.38, p=0.043; figure 1b). There was no significant effect of body mass on paternity in the model (i.e. once hierarchy size and position were accounted for: F1,38=2.07, p=0.16). Together, the variables included in the model explained 70% of the variance in paternity within male hierarchies.Figure 1.

Bottom Line: Salmon produced by hatcheries have lower fitness in the wild than naturally produced salmon, but the factors underlying this difference remain an active area of research.This paternity difference may result from inferior performance of hatchery males during sperm competition, female mate choice for wild males, or differential offspring survival.Regardless of its cause, the combination of inferior hierarchical position and inferior success at a position resulted in hatchery males having only half (51%) the reproductive success of wild males.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology , University of Western Ontario , London, Ontario, Canada N6A 5B7.

ABSTRACT
Salmon produced by hatcheries have lower fitness in the wild than naturally produced salmon, but the factors underlying this difference remain an active area of research. We used genetic parentage analysis of alevins produced by experimentally mixed groups of wild and hatchery coho salmon (Oncorhynchus kisutch) to quantify male paternity in spawning hierarchies. We identify factors influencing paternity and revise previously published behavioural estimates of reproductive success for wild and hatchery males. We observed a strong effect of hierarchy size and hierarchy position on paternity: in two-male hierarchies, the first male sired 63% (±29%; s.d.) of the alevins and the second male 37% (±29%); in three-male hierarchies, the first male sired 64% (±26%), the second male 24% (±20%) and the third male 12% (±10%). As previously documented, hatchery males hold inferior positions in spawning hierarchies, but we also discovered that hatchery males had only 55-84% the paternity of wild males when occupying the same position within a spawning hierarchy. This paternity difference may result from inferior performance of hatchery males during sperm competition, female mate choice for wild males, or differential offspring survival. Regardless of its cause, the combination of inferior hierarchical position and inferior success at a position resulted in hatchery males having only half (51%) the reproductive success of wild males.

No MeSH data available.