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

Abstract

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.

Cleaning the River Ganga: Impact of lockdown on water quality and future implications on river rejuvenation strategies

“…There has been a decline in fish catch along the river, suggesting a lack of supportive habitat and degradation of water quality. Destructive fishing, overfishing and the Farakka barrage were cited by fishers as the major causes of declines in fish catch from river–floodplain fisheries in Bihar ( Dey et al, 2020 ). Due to less discharge during the summer season, priority species like Gangetic dolphin and Gharial find difficulty in movement and are confined to few fragmented habitats.…”

A review of governance and tenure in inland capture fisheries and aquaculture systems of India

“…Threats and drivers of change in river, stream and floodplain fisheries: Apart from the existing impacts from dams, barrages, and pollution, climate change, economic development and a renewed interest in large infrastructure projects are among significant future changes that could impact the productivity of riverine capture fisheries (Sinha and Khan, 2001;Vass et al, 2009;Badjeck et al, 2010;Das et al, 2013aDas et al, ,b, 2016Das, Sarkar and Roy, 2019). These drivers can modify environments and create uncertainties that could limit knowledge systems and the capacity for adaptive management of riverine capture fisheries (Dey et al, 2020). Examples of climate change impacts include more extreme rainfall events, overall temperature rise and frequent droughts and glacial melt in rivers of Himalayan origin (Whitehead et al, 2015;Anand et al, 2018).…”

Influence of water quality, local knowledge and river–floodplain connectivity on commercial wild crayfish harvesting in the Atchafalaya River Basin

“…Priyambodo et al 2015). Although less studied than coastal fisheries, local environmental knowledge has been identified as a driver in fisher methodological decisions in other river-floodplain fisheries, including the Ganga River and Pamba-Achankovil River in India (Santha 2008;Dey et al 2019), Xingu River in Brazil (Mesquita and Isaac-Nahum 2015), and upper Zambezi River in Namibia (Abbott and Campbell 2009), and appears important to ARB crayfish harvesters as well. Unlike global inland capture fisheries that are commonly focused on local consumption (Welcomme et al 2010;Lynch et al 2016) and multiple species (Welcomme et al 2010;Kolding and van Swieten 2011), crayfish harvesters primarily focus only on crayfish during the season [with many switching to primarily blue crab Callinectes sapidus Rathbun for their season] and sell their catch to distributers for sale in large, regional urban centers; like fishers worldwide, local environmental knowledge is still an important decision making factor for these harvesters.…”