Fish diversity, community structure and ecological integrity of the tropical River Ganges, India

Abstract

The Ganges River is one of the largest river systems in the world and sustains a rich biodiversity of fish and fishers. In recent years, a decline in fish diversity and catch has become apparent due to various anthropogenic activities in the river basin. This study analyses the current fish diversity, distribution and community structure along the longitudinal gradient of the river and evaluates the ecological integrity of the riverine stretch applying a multimetric assessment approach. One hundred forty three fish species were recorded from the river and Cyprinidae was the dominant family. The middle stretch of the river exhibited dominance of small bodied erytopic, indigenous and exotic fish species with periodic and opportunistic life history strategies with significant decline of the large bodied prized Indian major carps. A tropic shift towards dominance of carnivore catfish species is evident. Non-metric multidimensional scaling revealed greater distribution and abundance of fish species with increasing river width and depth, higher sediment organic carbon, silt and clay along the river gradient. A significant change in the catches composition was evident from 1961 to 2010 in the middle stretch of the river at Allahabad. It reflected a progressive decline in proportion of Indian major carps (IMC) and the anadromous Shad Tenualosa ilisha and a significant increase in the proportion of exotic fish Cyprinus carpio and Oreochromis niloticus which represented 43–48% of the total catch. Assessment of biotic integrity showed that 28% of sample locations in the river supported fish assemblages under acceptable conditions.

Identifying potential causes of fish declines through local ecological knowledge of fishers in the Ganga River, eastern Bihar, India

“…Flow regulation and alteration by dams and barrages, pollution and overfishing of spawn have been unequivocally identified as the major drivers of fishery declines by many studies (Das et al, 2013;Jhingran & Ghosh, 1978;Kelkar, 2014b;Payne et al, 2004;Payne & Temple, 1996;Sarkar et al, 2012;Talwar & Jhingran, 1991). The spatial scale of these studies was basin-wide so flow alterations were identified as the main threat.…”

“…Fish stocks in the Ganga River have been declining (Das et al, 2013;Payne et al, 2004;Payne & Temple, 1996;Ray, 1998;Sarkar et al, 2012;Vass et al, 2009). In the Ganga River in Bihar, open-access river-floodplain fisheries from 1991 onwards have brought severe conflicts over fishing rights and access to fishing areas.…”

Freshwater fishes of Orissa, India

“…Orissa constitute about 18.11% to the freshwater fish fauna of India (Dutta et al 1993). Earlier reports on freshwater fish fauna of Odisha such as Hora (1938Hora ( , 1940, Misra (1938), Chauhan (1947), Jayaram and Majumdar (1976), Dutta et al (1993), Ramakrishna et al (2006), Pathak et al (2007), Karmakar et al (2008), Das (2008), Baliarsingh et al (2013), Mishra et al (2013), Singh et al (2013), Behera and Nayak (2014), Satapathy and Misra (2014), Singh (2014), Dandapat (2015), Mohanty et al (2015), Sarkar et al (2015), Das et al (2016) and Samal et al (2016) agreed with dominance of cyprinids over other freshwater fish families. The dominance of cyprinid species in natural water bodies is common all over the South Asia and reported in several studies (e.g.…”

“…Offline search include offline journals, textbooks, reports and gray literature those are not available online. Pathak et al (2007) River Mahanadi 112 Karmakar et al (2008) Subamarekha River in Mayurbhanj and Baleswar districts 13 Das (2008) Ansupa Lake in Cuttack district 23 Baliarsingh et al (2013) Freshwater bodies from Similipal Biosphere Reserve, Mayurbhanj district 55 Mishra et al (2013) Baitarani River at Jaipur district 25 Singh et al (2013) River Mahanadi 96 Behera and Nayak (2014) Chilika lake in Puri, Khurda and Ganjam districts 14 Satapathy and Misra (2014) River Pilasalunki at Phulbani district 23 Singh (2014) River Mahanadi: Hirakud Reservoir, Satakosia, Kantilo, Banki 56 Dandapat (2015) Samuka River near Sahada Village in Balasore district 10 Mohanty et al (2015) Chilika lake in Puri, Khurda and Ganjam districts 71 Sarkar et al (2015) Ansupa Lake in Cuttack district 28 Das et al (2016) River FIGURE 1 Reported locality of freshwater bodies in Orissa, India (map source: Google Earth)…”

Life aquatic: the amazing self-purifying properties of the Ganges River.

“…(2) The Ganges harbours a surprising amount of biodiversity, including the gorgeous Ganges river dolphin, the widely feared Ganges shark, and the awkward-looking gharial crocodile, which can be up to 20 feet in length. (3) Unfor- Self-purifying properties of the Ganges River Scoping Review tunately, many of the interesting animals that inhabit the Ganges are endangered, and many others have long gone extinct.…”