Putative extinction of Cobitis kellei: Evidence from Repeated Field Surveys and Hydrological Collapse

Abstract

Cobitis kellei, a loach species endemic to the stream Göksu in upper Tigris drainage / Türkiye, has not been observed since its first and only collection in 1974. Despite a previous assessment listing it as Critically Endangered (CR), no confirmed sightings have occurred within the last five decades. 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 were found. Supported by long-term anthropogenic degradation of the stream ecosystem, we propose the formal extinction of Cobitis kellei.