Ecological and anthropogenic factors shaping fish survival in Kashmir streams

Abstract

The Himalayas harbor one of the most diverse assemblages of freshwater hill stream fishes, shaped by steep environmental gradients such as altitude, temperature, and flow rate. This review synthesizes current knowledge on how these gradients influence fish diversity, distribution, and physiological adaptations. Unlike earlier descriptive accounts, this paper critically examines the ecological and physiological mechanisms underlying species’ responses to environmental stressors, with attention to recent advances in climate and conservation research. The review also highlights urgent conservation challenges—hydropower development, habitat fragmentation, pollution, and climate change—and evaluates ongoing initiatives in the region. Specific recommendations are proposed, including maintaining environmental flows, restoring riparian zones, and developing community-led conservation models. A systematic literature review framework was employed to identify relevant studies from 2000–2025, ensuring comprehensive coverage of both classical and recent works. This study emphasizes the need for integrated research on diversity, physiology, and conservation to safeguard Himalayan hill stream fishes. One of the most diverse assemblages of freshwater hill stream fishes inhabits the Himalayas, shaped in steep environmental gradients of altitude, temperature, and flow rate. This review synthesizes the knowledge on how those gradients shape fish diversity, distribution, and physiological adaptations. Unlike earlier accounts that were largely descriptive, this paper places ecological and physiological mechanisms of species responses to environmental stressors into focus, with due attention to recent advances in climate and conservation research. It highlights urgent conservation challenges-hydropower development, habitat fragmentation, pollution, and climate change-and assesses ongoing initiatives in the region. It puts forward specific recommendations: maintenance of environmental flows, restoration of riparian zones, and community-led models for conservation. For this purpose, a systematic literature review framework was used to identify relevant studies from both classical and recent works between the years 2000-2025. The study argues for an integrated research approach on diversity, physiology, and conservation to safeguard Himalayan hill stream fishes.