Native Himalayan fish species facing onslaught of exotic brown trout species, finds WII study

The researchers have argued that the exotic brown trout is increasingly popular due to recreational angling and food delicacies.

A new study has found that the native Himalayan snow trout is facing the onslaught and invasion of the exotic brown trout which are not only restricting the species distribution but also hindering their movement in the high altitude river basins. The study which has been published in the Journal of Applied Ecology noted that the Himalayan snow trout prefer to inhabit the downstream or the mainstream of the river segment for healthy chances of its survival. The study has found that a large number of brown trout is forcing the snow trout to shift to the upper stream of the river segment, the Indian Express reported.

Aashna Sharma who is associated with the Wildlife Institute of India (WII) in Uttarakhand told the Indian Express that the development is very concerning as the snow trout can only find sub-optimal habitat in the upper stream of the river. She also said that the upper stream cannot support the entire life of native snow trout. To the question of how things came to this pass, Sharma said that the development is a disastrous outcome of common preference for the invasive brown trout for sport leisure and delicacy choices that people prefer. The researchers have argued that the exotic brown trout is increasingly popular due to recreational angling and food delicacies.

The researchers also underscored the fact that the exotic brown trout was first introduced in the water of the Himalayas by the British primarily for sport. So far as the probable mitigation strategy against the development goes, researchers have stressed on the importance of not constructing dams and multi-purpose projects in the upper streams of the segment.

Study co-author J. A. Johnson from WII has noted that the indigenous snow trout is an iconic and indispensable species of the high altitude Himalayan rivers ranging from Jammu and Kashmir to Arunachal Pradesh. Johnson added that since not much information is available about the host of other species inhabiting the high altitude Himalayan rivers, snow trout is regarded as a keystone species and an indicator for the overall health of the entire river ecosystem.