Life history variation of invasive mosquitofish (Gambusia holbrooki) along a salinity gradient

摘要: The mosquitofish (Gambusia holbrooki) is among the most invasive fish worldwide, with well documented ecological impacts on ecosystem functioning and several native taxa. Although it has been suggested that salinity limits success of mosquitofish, there are few studies how affects its ecology. We examined differences in life history traits at 19 sampling sites from fresh (438 μS/cm; ca. 0.2‰ salinity) to polysaline waters (35.1 mS/cm; 23‰). Salinity affected density both male female mosquitofish; showed a unimodal response salinity, stronger for females thus affecting sex ratio. On other hand, endemic Aphanius iberus was only present eusaline waters, where were generally absent. Mosquitofish increased reproductive investment (higher gonadal mass) oligosaline cost somatic condition females. increase also implied an total mass contrast mass, demonstrating latter better indicator condition. Females higher presented more embryos advanced developmental stages, indicating earlier reproduction than water. After correction brood sizes, saltier environments heavier (independently maturation state). In summary, mainly which, despite presenting investment, reduced their density, hence supporting hypothesis success.