Genetic diversity and population structure of the non-native Eastern mosquitofish (Gambusia holbrooki) in Mediterranean streams

<p>Mosquitofish is a small, voracious, highly fecund freshwater fish species originated from northeastern America, that was introduced worldwide to control mosquito populations. In this thesis we have studied the genetics of the invasion of Mediterranean streams by the mosquitofish (<em>Gambusia holbrooki)</em> to discover some of the aspects that drive their successfully invasive life history. Comparison of introduced populations with the American sources of invasion indicated that there was no loss of genetic diversity due to the invasion process. Local genetic diversity levels and overall population structure were maintained among generations in introduced populations. We observed adaptive response to pollutants in the Flix reservoir, Ebro River, but that human perturbations do not prevent mosquitofish dispersal along rivers. Finally, unregulated human-assisted translocations probably increase the opportunities for colonization of new environments, and therefore need to be controlled.