Sperm competition between alternative reproductive tactics of the Atlantic salmon in vitro
2010
Vladić, Tomislav | Forsberg, Lars A. | Järvi, Torbjörn
The maintenance of brood stock in appropriate conditions is an important requirement for the production of high quality offspring. In this study, we investigated fertility of the two life history forms of Atlantic salmon males, precocious parr, brought up in breeding tanks in the hatchery and anadromous, migratory sea-ranched males, caught when returning to the home river. The sperm quality was assessed by experiments between equal amount of sperm from one adult and one parr male in competition to fertilize eggs of a single female. The paternity was determined by a microsatellite analysis. Parr males achieved greater reproductive success than anadromous males under competition, and anadromous adults had greater fertility in controls as compared to the sperm competition situation. In total, parr males achieved 3.6 times greater fertilization success than anadromous males. Sperm ATP content contributed significantly to male fertility. Our results provide evidence that ejaculates of precociously mature Atlantic salmon parr are of increased quality as an adaptation to high sperm competition intensity due to better maintenance in the fish farm than in the wild.
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