Search

Local ecological knowledge (LEK) can offer insights into fisheries management by describing long‐term changes that are difficult to unravel in data‐poor river‐floodplain fisheries. LEK is derived from complex interactions between fishers' observations of environmental change and their institutional capacities to manage fisheries. Hence, it is important to understand where and how LEK and formal scientific studies on fish species' decline could complement each other. In this paper, the causes of decline of 58 fish and two shrimp taxa were identified from LEK data (1999–2019) obtained from river–floodplain fisheries of the Gangetic plains (Bihar, India). Qualitative analyses of LEK were used to generate species‐specific hypotheses and historical insights on their declines. Destructive fishing, overfishing and the Farakka barrage were cited by fishers as the major causes of declines. Potential reasons for these perceptions were explored in relation to fishers' experiences of conflicts in the region over fishing rights and access. [ABSTRACT FROM AUTHOR]

Ganga, the national river of India, is now sadly depleted in flow and utterly polluted due to construction of dams and barrages, discharge of untreated municipal and industrial wastes, floral offerings, cremation of dead bodies on its bank. Kanpur to Trighat is identified as the most polluted section of the river. This critical state of the river has been revealed in the paper based on an analysis of the published accounts and research results by various institutes and individuals. It also sheds light on the strategies and action plans to rejuvenate the Ganga to its pristine quality. [ABSTRACT FROM AUTHOR]

The lower stretch of Gangetic delta in the Indian sub-continent is noted for its rich mangrove biodiversity, natural calamities, and livelihood-supporting matrix of millions of people and is the only mangrove base of Royal Bengal tiger (Panthera tigris tigris) in the planet Earth. The present trend of industrialization, urbanization and construction of barrage in the upstream zone has changed the landscape of the deltaic complex and the characteristics of the aquatic sub-system have also changed accordingly. This ecosystem offers an ideal site to study a number of physico-chemical parameters in relation to changing scenario of the region. The presence of heavily populated cities of Kolkata, Howrah and the Haldia industrial belt on the bank of the Hooghly estuary has made the mighty River Ganga highly vulnerable to anthropogenic stress. Spatial and tidal variations of important physico-chemical parameters in the Hooghly estuarine stretch of Gangetic delta complex were studied during the summer month April, 2008. The water quality reflects the impact of Bay of Bengal (sea) water almost on all the variables as revealed from the significant difference of parameter values in high and low tides (except surface water temperature and potassium). The 12 selected stations from the upstream to downstream regions exhibited uniformity with respect to surface water temperature. Significant spatial variations (at 5% level of significance) were observed with respect to parameters like surface water salinity, pH, alkalinity, DO, BOD, COD, NO3, PO4, SiO3, extinction coefficient, SO4, Na, K, Cl and total nitrogen. Along with tidal influences, the anthropogenic factors contributed by the adjacent cities and towns exert a regulatory influence on parameters like BOD, COD, NO3, PO4, extinction coefficient, SO4 and total nitrogen. [ABSTRACT FROM AUTHOR]

The Tapi is a major interstate, westerly flowing river with 14 tributaries, of which the left bank tributaries support large settlements in Maharashtra State. It has been identified as one of the water scarce basins of India. There are many dams and barrages in the basin to store and divert water for agricultural and industrial purposes. This results in low flow and deterioration of water quality in the region particularly in non‐monsoon months. This paper presents the details of a GIS‐based rainfall‐runoff modelling study carried out to assess the runoff flow in the sub‐catchments and at the outlet of the Tapi Basin. Using mean monthly rainfall data at seven gauging stations in the basin, and land use and soil characteristics as reported by the Central Pollution Control Board (CPCB), the annual runoff flow at the watershed outlet was estimated to be 18,814 MCM. A comparison of runoff generated in the sub‐catchments and the observed runoff at Central Water Commission (CWC) monitoring stations is presented. Results of the simulation indicate that the reduced river flows caused by the number of dams/reservoirs constructed upstream are useful as a guideline for the development of environmental flow regulations for rivers and streams in the Tapi Basin. [ABSTRACT FROM AUTHOR]