First Report on Invasion of Exotic Carp, Cyprinus carpio var. communis (Linnaeus, 1758) in a Himalayan River - Reservoir Ecosystem

Cyprinus carpio var. communis, an invasive exotic species, has been recorded for the first time as one of the most dominant species in reservoir and river-reservoir interface of Bichom, Arunachal Pradesh, India, in an investigation during May 2022–June 2023. The intensity of its invasiveness was very high, as evidenced by the relative abundance with an average catch of 0.26–2.90 kg/net/day. This species dominated the catches, contributing 5.5 kg/net/day to the total catch of the reservoir. A deeper survey has revealed that this exotic common carp entered the river and reservoir system from the nearby culture ponds of C. carpio during the flood that occurred in 2019 and has been established in the Bichom river-reservoir ecosystem. This is the first case report on the occurrence and invasion of C. carpio in the Bichom River and reservoir system, Arunachal Pradesh. The information generated here could be utilized as benchmark information on the geographic expansion of C. carpio in the river Bichom, a Himalayan river-reservoir ecosystem.