Status of fish assemblage structure in the Ganga and Indus riverine systems of the western Himalaya

Abstract The Ganga and Indus riverine systems are the major freshwater resources in the western Himalaya. The aim of this review was to critically analyze the status of inland fisheries in both the Ganga and Indus Riverine systems of the western Himalaya. Data from secondary sources such as research publications, scientific documents, technical advisories, and books were retrieved. The fish diversity of both riverine systems reveals that the number of endemic and native species like Tor tor , Tor putitora , Glyptothorax spp., Nemacheilus spp., and Schizothorax richardsonii is decreasing. Moreover, in most of the rivers of both riverine systems, exotic species, especially those belonging to the Cyprinidae family, for example, Cyprinus carpio , are increasing and are also dominant, followed by the families Cobitidae and Sisoridae. The Ganga and Indus riverine systems' diverse fish populations have declined because of various anthropogenic activities, especially water pollution and dam construction, which are responsible for the change in river hydrology. Frequent data were available on the Ganga riverine system, which shows a continuous decline in fish diversity. A similar trend was observed in the lower stretches of the Indus riverine system. But negligible information was available on the upper stretches of the Indus riverine system; this may be due to a large research gap. However, adequate knowledge of both river systems is necessary to develop conservation and management strategies for the sustainable development of fishery resources in India in the future.