Exploring of alien fish species diversity in Amochhu of Bhutan

Abstract

A number of alien fish species are introduced into aquatic ecosystem undermining their adverse impacts to the natural ecosystem, despites having a good ichthyofauna diversity inclusive of some endemic fish species in Bhutan. The survey was undertaken to explore and document alien fish species diversity in Amochhu and Haachhu due to high vulnerability from anthropogenic influences. A total of 13 sites -11 sites at Amochhu and one site each from adjoining fish hatcheries at National Research and Development Center for Riverine and Lake Fisheries, Haa and National Research and Development Center for Aquaculture, Gelephu were selected for the survey. The present survey recorded 37 fish species inclusive of five alien fish species namely Cyprinus carpio, Cyprinus carpio, Ompok pabda, Clarias gariepinus and Salmo trutta. The presence of Cyprinus carpio, Clarias gariepinus and Salmo trutta was confirmed in wild habitat; whereas, Oreochromis mossambicus was observed established under confinement. The current survey found out that the Salmo trutta had established a self-sustaining population, and Ompok pabda was recorded for the first time in Amochhu. However, this survey could not ascertain the pathway of introduction of those alien fish species. There is a need for the government to intervene and put in proper policy measures to control introduction of both alien and cultured fish species in waterbodies of Bhutan; and in parallel, it is felt important to educate general public on the consequences of introducing alien fish species into the waterbodies.