Habitat Suitability of Nayar River as Breeding and Nursery Grounds for Endangered Tor putitora in the Lower Himalayan Stretch of the Ganga River System

The Nayar River serves as a home to the fry, fingerlings and juveniles (residents) of Golden Mahseer, Tor putitora , where the brooders ascend annually for spawning (migrants) in search of suitable breeding cum nursery grounds from their abode in the Ganga. Here, we statistically explored the relationship of residents and migrants to ecologically relevant water parameters, land use land cover, and anthropogenic variables in the Nayar River. From July 2021 to June 2022, the samples of river water and Golden Mahseer were collected from six sampling stations at monthly intervals. Concurrently, a stretch of 44.54 km 2 of the immediate river valley was examined for the basin land cover. Based on variability within the respective stations, the clustering analysis classified the sampling stations into three clusters. The chi‐square value ( p < 0.05) of the observed variables supported the use of canonical correspondence analysis (CCA) for selected variables in both residents and migrants. The Cos 2 metric, an extension of the CCA biplot, identified the relation of the examined variables with different Mahseer inhabitants. The Cos 2 metric showed a strong correlation of migrants with current velocity, electrical conductivity, water temperature, pH, fishing pressure and riverbed substrates, while mining, rural areas, vegetation cover and electrical conductivity strongly correlated with residents. The study suggests a need for strict regulation on fishing, mining, and other anthropogenic activities along the river as the aggregate effects are negatively impacting the habitat quality for both residents and migrants of Golden Mahseer in the breeding cum nursery grounds of the Nayar and its Western and Eastern tributary.