Multidimensional crisis in the conservation of Amu Darya false shovelnose sturgeons

A robust reassessment of extinction risk is crucial for developing evidence-based conservation strategies and preventing irreversible biodiversity loss. Sturgeons are among the most threatened freshwater fishes worldwide, yet extinction risk evaluations for the critically endangered Amu Darya false shovelnose sturgeons (Pseudoscaphirhynchus kaufmanni and P. hermanni) still largely depend on legacy information that does not reflect recent human disturbances. To re-evaluate the extinction risk of these sturgeons, we combined updated occurrence records, traditional morphometric data, mitochondrial genetic markers, and ethnobiological surveys from field expeditions, market inspections, and community interviews conducted during 2019-2024. Our results showed dramatic contraction in distribution range and an almost complete loss of population structure. The long-snouted form of P. hermanni is likely already extinct, and the short-snouted form now persists only in fragmented habitats in the middle and lower Amu Darya. Morphological comparisons revealed a marked decrease in body length and weight, indicating size-selective removal linked to illegal poaching. Genetic analyses also revealed declining diversity and signals of demographic bottlenecks, consistent with severely reduced adaptive potential. Taken together, our results indicate an urgent need for coordinated transboundary conservation to avert the imminent extinction of the two critically endangered species.

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