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Proc Biol Sci. 2001 November 22; 268(1483): 2375–2381.
PMCID: PMC1088889

Sperm quality in the alternative reproductive tactics of Atlantic salmon: the importance of the loaded raffle mechanism.


The outcome of sperm competition in species with alternative male reproductive strategies may be determined by fair or loaded raffle mechanisms. The sperm production and quality of male Atlantic salmon using alternative reproductive tactics were investigated in order to determine the relative importance of sperm quality for male reproductive success. Sexually mature resident parr males produced greater numbers of spermatozoa per millilitre of ejaculate and invested more in their gonads as a percentage of body mass than their anadromous counterparts. Parr males had greater proportions of motile spermatozoa and a greater sperm ATP content as compared with anadromous males. Parr males invested relatively more in sperm quality and sperm numbers after the effect of body size was accounted for. In fertilization experiments, parr males fertilized greater proportions of eggs than anadromous males. A polynomial model exhibited a trade-off between testes mass and ejaculate expenditure and explained 60% of the variation. These results establish that, in sperm competition with dominant males, parr males may compensate for behavioural subordinance by producing physiologically superior spermatozoa.

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Selected References

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  • Thomaz D, Beall E, Burke T. Alternative reproductive tactics in atlantic salmon: factors affecting mature parr success. Proc Biol Sci. 1997 Feb 22;264(1379):219–226. [PMC free article]

Articles from Proceedings of the Royal Society B: Biological Sciences are provided here courtesy of The Royal Society