Putative extinction of Cobitis kellei: evidence from repeated field surveys and hydrological collapse

Abstract

Cobitis kellei, a loach species endemic to the Göksu Stream in the upper Tigris drainage (Türkiye), has remained long-lost since its first and only collection in 1974 and was previously assessed by the IUCN as Critically Endangered (CR). Here, we report the results of extensive field investigations conducted between 2016 and 2021 using standardized backpack electrofishing surveys across the entire known range of the species. Our data document a complete hydrological collapse of the habitat, with no individuals of the species found. Supported by long-term anthropogenic degradation of the stream ecosystem, we hypothesize the extinction of C. kellei.