Decoding climate response: future of native snow trout and non-native brown trout in Himalayan rivers

Dr Vineet Dubey1, Ms Aashna Sharma1, Dr Jeyaraj Johnson1, Dr Kuppusamy Sivakumar1

1Wildlife Institute Of India, Dehradun, India

Successfully established wild populations of non-native brown trout (Salmo trutta fario) in higher altitude of Himalaya raise concerns for conservation of native snow trout (Schizothorax richardsonii) species over the past years. As such, assessing the way invasive-exotics and natives would respond to changing climate in vulnerable Himalayan riverscapes is of utmost importance.

The objective of the present study was to model the bio-climatic niches of native and non-native trout distributed throughout the high altitude Himalayan regions and create a set of projections under a collection of climate change scenarios. Our modeling approach was based on Generalised Linear Model, Generalised Additive Model, Generalised Boosting Model and Random Forests. All these models were integrated into ensemble forecasting approach for future predictions.

Biological investigations in the present study revealed empirical evidences on fast reproduction, better body conditions, and a short life-cycle facilitating the non-natives as potential competitors over the native trout. The range shifts of both native and nonnative trout raise concerns on the former as the exotic trout showed more flexible adaptive strategies in view of early maturation and fast reproduction.

The present study is a first step to link the species distributions models and biological traits of prime coldwater fishes of fragile Himalaya to better understand species-specific idiosyncratic response. Further, delineating the potential refuge for these wild populations would provide better insights for the protection of key watersheds areas and adopting mitigation strategies for future climate planning.


Dr Vineet Dubey is a research associate from Wildlife Institute of India and is studying the freshwater ecology and species associations in the Indian Himalayan Region. His doctoral work comprised comparisons of pre and post river interlinking  scenarios. He has experiences on wildlife surveys in National Parks and Tiger Reserves of India, a major one being all India Tiger estimation. He loves traveling, photography and wildlife exploration, all time favorite being in Himalaya.

Ms Aashna Sharma is a Senior Research Fellow pursuing her doctoral work on native-exotic trout interactions in the Himalayan Rivers. She has done extensive surveys on the aquatic fauna of high altitude Himalayan Regions including trans Himalaya. She has particular interest on macroinvertebrates of cold water streams. She loves singing, poetry and trekking to unexplored lands

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