Climate modification will speed spread of invasive fish to northern Europe

Spanish and French researchers have evaluated the spread of the invasive mosquitofish Gambusia holbrooki, which is native to the us and lives in Mediterranean rivers in Spain and France. The scientists warn that climate change will extend the current distribution area of this and other invasive species to the north.

“This study shows that temperature affects the abundance of this species, its reproduction and other characteristics of its life cycle”, Emili García-Berthou, lead author of the study and a researcher at the UG’s Institute of Aquatic Ecology, tells SINC.

“Over a latitudinal gradient greater than 5º, the abundance of this species in river mouths varies, as do its reproductive effect, its size at maturity and prevalence of parasites”, the Catalan researcher adds.

The research team sampled a total of 929 gambusias during the warm months of 2004 in the mouths (final 1,500 metres) of eight Mediterranean rivers from the south of France to Murcia.

Although this ecological impact has been “well documented” in america and Australia, other studies in Spain have used observational and experimental data to show that Gambusia holbrooki “competes with and displaces cyprinodontiform fish (small fish that live in fresh or brackish water), like the Spanish toothcarp (Aphanius iberus) and the Valencia toothcarp (Valencia hispanica), both of which are endemic to the Peninsula and have seen their distribution area greatly reduced, now being thought to be at risk of extinction”, explains García-Berthou.

Spain was the first European country in which Gambusia holbrooki was introduced, in 1921.