Preface

Rivers have played a fundamental role in the lives, history, and culture of mankind and civilization since pre-history. Early societies grew on the banks of the great rivers of the world. Similarly, rivers have been the lifeline of India's ancient culture. The river Sindhu (Indus) and the Indus valley became the cradle for the development of one of the earliest civilizations. The Ganga (Ganges River), arguably the most written-about river in the world, has been called the Mother of India's spirituality and has been immortalized in sculpture, art, literature, poetry, music, and dance. The drainage basin of the Ganges covers one of the most populated regions of the world, where the Indo-Aryan civilization has flourished for many centuries. Along with these two famous waterways, the major rivers of India harbour extremely rich biodiversity and contribute significantly to the food security and livelihood of India.

The riverine resources of India, covering the length and breadth of the country, connect people of diverse culture, lifestyles, and languages. The Indian mainland is drained by 14 major (drainage basin >20,000 km²), 45 medium (2,000 to 20,000 km²), and over 120 minor (<2,000 km²) rivers, in addition to numerous ephemeral streams. These river systems are grouped, according to their origin, into Himalayan and Peninsular rivers. Rivers Indus, Ganga, and Brahmaputra are the three major rivers, which together with their many tributaries, originate in the Himalayas. Their basins cover nearly two-thirds of the Indian subcontinent and are among the most densely populated regions of the world. The Ganges is the longest river of India, with a total length of 2,525 km, while the Brahmaputra is the third largest river in the world, with a distance of 918 km traversing the country. Rivers Ganges and Brahmaputra form extensive floodplains and a delta, the Sunderbans, which ranks among the largest in the world. A substantial part of northwestern India is included in the Indus drainage basin, which is shared with China, Afghanistan, and Pakistan.

Peninsular drainage into the Bay of Bengal from the east coast river system includes a number of major rivers, most notably the Mahanadi, Brahmani, Godavari, Krishna and Kaveri (Cauvery). Except for the Mahanadi and Brahmani, the headwaters of these rivers are in the high-rainfall zones of the Western Ghats, and they traverse the entire width of the plateau before reaching the Bay of Bengal.

The west-flowing peninsular rivers draining into the Arabian Sea include the rivers Luni, Sabarmati, Mahi, Narmada, Tapi (Tapti) and many small rivers originating from the Western Ghats. River Narmada, with a length of 1,289 km, and River Tapi, at 724 km, originate in the state of Madhya Pradesh and are prominent among west-flowing rivers in the country.

Rivers provide substantial ecological functions, services, and value to society. A large number of people in India depend on riverine fisheries for their livelihood. They also play a major economic role for the country in sustaining agriculture, industry, and energy generation, as well as providing biological resources. The diverse river system in India harbours one of the richest fish genetic resources in the world, and a complex mix of artisanal, subsistence, and traditional fisheries. With an estimated 930 species, India ranks eighth in the world and third in Asia for freshwater fish species diversity. Rivers flowing through the Eastern and Northeastern Himalayas and Western Ghats have been designated as global hotspots of freshwater biodiversity.

In recent decades, India's water resources, and especially her rivers, have been exposed to various anthropogenic stresses. Human greed and abuse have degraded these ecosystems significantly. Many rivers are severely impacted, resulting from channel and bank modifications, flow regulation and fragmentation, and chemical and organic pollution. Because of these uses, several long reaches of rivers passing through urban areas remain completely dry for large parts of the year, except during the monsoon. Consequently, flood plains are lost and river beds are even cultivated during dry periods. As a result of such habitat degradation, fish catches have greatly declined, the size of important indigenous fish species has decreased, and fish recruitment has been seriously affected.

The impact of human activities is already manifesting and is reflected by declining fisheries, increasing incidence of floods, lowered groundwater tables, and growing incidence of waterborne diseases. Since independence in 1947, India has witnessed rapid, unplanned urbanization in addition to industrialization and intensification of agriculture. As a consequence, the natural environment has deteriorated including the river water quality of many Indian rivers and at a rapid pace. One of the major reasons for this is the release of untreated wastewater to the rivers. It is indeed a matter of extreme concern that out of the world's 30 river basins identified as global level priorities for maintenance and protection of aquatic biodiversity, ten of these are Indian, namely: Brahmaputra, Cauvery, Ganges, Godavari, Indus, Krishna, Mahanadi, Narmada, Pennar and Tapi.

Conservation and management of rivers in India only started receiving some attention in the last 40 years. Considerable emphasis has been placed on the improvement of water quality through interception, diversion, and treatment of domestic sewage and industrial effluents. However, water quality continues to deteriorate further, largely due to the reduction or total absence of flow and increasing degradation of the watershed. Looking to the future, it is important for India to take a new approach to the management of its riverine resources. The growing emphasis on biota and ecosystems has led many researchers to embrace the term ‘river health,’ giving a sense of the integration of physical, chemical, and biological characteristics to differentiate ‘healthy’ from ‘sick’ riverine ecosystems. There are many indicators of river health used by ecologists worldwide at scales large enough to be useful for management. These include measures of structure and function of both biotic and physical components.

Data available on the fishes, fisheries, and the health of these rivers in India are fragmented and scattered. To remedy this glaring lacuna, the Central Inland Fisheries Research Institute (CIFRI)—a premier research organization of India—has generated a valuable database dealing with the ecology, biodiversity, fisheries, aquatic health, management, and conservation of major Indian rivers over the past several years. During the 8^th Fisheries Forum symposium in Kolkata, November, 2008, it was suggested that a concerted effort be made to collect, compile, and integrate the available literature and data on the major rivers of India. This will lead to a realistic and scientific assessment of the current status of the health of these rivers. In order to fill in the information gap, the Aquatic Ecosystem Health and Management Society (AEHMS) published a special issue of Aquatic Ecosystem Health & Management (AEHMS, 2010) that included a compendium of peer-reviewed articles focusing on the ecosystem health of the Ganges based on papers presented at the fisheries forum in 2008. Since then the joint collaboration has continued between CIFRI and AEHMS. To maintain the momentum, plans for two additional publications were drawn up following an organizational meeting held in New Delhi during February 2011, namely:

1. Ecosystem health and management of River Ganges

2. Health and fisheries of the major river ecosystems of India

In order to proceed with publication plans, an authors' workshop entitled “Ecosystem Health of Major Rivers of India: River Ganges Case Study” was organized jointly by CIFRI and the AEHMS in Barrackpore during April 2012, where contributors presented their research findings. As a result of this workshop and a follow-up meeting in July 2012, several papers were submitted to the AEHMS for publication. At this juncture, it was felt that it would be useful and productive to organize a special India-wide symposium to provide a broad platform for scientists to share their research findings on the history, ecology, biodiversity, geomorphology, hydraulics, conservation, and management of the River Ganges, as well as other major rivers of India.

A great opportunity emerged, to convene a collaborative symposium by CIFRI, AEHMS, & Inland Fisheries Society of India (IFSI) in celebration of a great event: the 100th Indian Science Congress at Kolkata. A symposium entitled, “Health and Fisheries of Major River Ecosystems of India with emphasis on River Ganges” (Kolkata, India, 5–6 January 2013) was convened during which over 40 papers were presented during the two days of deliberations. This provided an excellent collection of top-down assessment of the status of the ecosystem health of Indian rivers.

Based on the Indian Science Congress symposium, two publications were planned: namely a special issue (AEHMS, 2013) entitled, “Ecology of the Mighty Ganges: Health, Fisheries and Management” as well as this double issue, regarding the ecology of Major Rivers of India.

In this special double issue, 15 articles have been compiled, covering river systems from the Western Ghats to northeastern rivers. These articles focus on the ecology and management of inland fisheries, including fish and benthic diversity, ecological integrity, water quality, conservation prioritization strategies based on fish assemblages, threats and conservation challenges to key aquatic fauna like crocodiles and dolphins, and impact assessment of river-linking projects. This issue also discusses historical, cultural and socioeconomic aspects of fishers in India. It is hoped that it will be a valuable resource for researchers, managers, teachers, students, and policy makers involved in riverine environments and fisheries management.

Finally, we would like to thank all contributors to the special issue and the AEHMS team: I. F. Munawar (Managing Editor), Jennifer Lorimer, Robin Rozon, Susan Blunt, Lisa Elder and Mark Fitzpatrick.

 

“Ganga has been a symbol of India's age-old culture and civilization, ever-changing, everflowing, yet the same Ganga.”

Pandit Jawaharlal Nehru

Prime Minister of India

From his will and testament