Length–weight relationships of invasive mosquitofish (Gambusia holbrooki Girard, 1859) in 23 river basins of Turkey

Gambusia holbrooki Girard, 1859 has established very strong populations in freshwater resources in Turkey after being introduced into Amik Lake (Hatay/Antakya) at the beginning of the 1920s. In this study, it was aimed to determine the female:male ratios and length-weight relationships of G. holbrooki populations in Turkey, which are considered as a threat, especially for endemic species. G. holbrooki specimen were sampled at total of 66 locations, including 39 lentic and 27 lotic locations, between 2016 and 2017. The female:male ratio was 1:0.39 for all of the investigated localities.