Sex-specific effects of outbreeding on offspring quality in pike (Esox lucius)

Intraspecific genetic admixture occurs when previously separated populations within a species start interbreeding, and it can have either positive, negative or netural effects on reproductive performance. There is currently little knowledge regarding what determines the outcome of admixture. We tested for effects of admixture on offspring quality in three subpopulations of pike (Esox lucius). Gametes were collected in the field, and eggs from each female were experimentally fertilized with milt from a male from each population (one ‘pure’ and two ‘admixed’ treatments). Three offspring quality measures (hatching success, fry survival, and fry length) were determined and compared between (i) pure and admixed population combinations, and (ii) the sex-specific treatments within each admixed population combination (based on the origin of the male and female respectively). The results revealed that although there were no overall effects of admixture on offspring quality, the consequences for ...