The endangered Ganges river dolphin heads towards local extinction in the Barak river system of Assam, India: A plea for conservation

Choudhury, Nazrana Begam; Mazumder, Muhammed Khairujjaman; Chakravarty, Himabrata; Choudhury, Amir Sohail; Boro, Freeman; Choudhury, Imrana Begam

doi:10.1016/j.mambio.2019.03.007

Cited by 17 publications

(9 citation statements)

References 25 publications

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“…Only 44.44-62.30% of KL fishers receive incentives (Figure 5), whereas most do not. Although incentive schemes have been shown to motivate fishers to follow fishing rules in hilsa fisheries [17], the inclusion of fishers in KL fisheries has yet to be considered for incentive provision, despite their limited capacity to cope with the temporal and spatial closure [18,19]. Despite their great socioeconomic value, only a few limited studies have focused on the socioeconomic aspect of fisheries [20][21][22].…”

Section: Discussionmentioning

confidence: 99%

Analyses of Protection and Conservation According to the Fish Act 1950 in Bangladesh’s Kaptai Lake Fisheries Management

Rayhan

Schneider

Islam

et al. 2021

Water

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Kaptai Lake (KL), the largest inland watershed in Bangladesh (ca. 700 km2) and one of Southeast Asia’s largest artificial reservoirs, features an abundant variety of indigenous fishery species. Moreover, it provides a plethora of ecological benefits to society. Nevertheless, the KL is suffering from multidimensional natural and anthropogenic stressors that threaten these wetlands’ sustainability. Though the legal framework assures sustainable conservation of fisheries resources, the implementation scenarios of fisheries laws, regulations, and policies in the KL wetland are insufficient. This study aimed at assessing the fisher’s perception of the regulation implementation efficiency of the Protection and Conservation Fish Act of 1950, while analyzing the effectiveness of the legal framework in the context of biodiversity conservation and the management sustainability of KL. By integrating qualitative and quantitative data collected through participatory Rural Appraisal (PRA) tools viz. 225 interviews with fishers, four focus group discussions, and 12 key informant interviews, the investigation was performed in four selected areas in KL. The findings show that fishers routinely disregard laws and restrictions of the Protection and Conservation of Fish Act 1950 due to various socioeconomic and political forces. Although the annual fish harvest rate from KL appears to be increasing, the lake is losing its charismatic biological diversity primarily due to inappropriate and ineffective enforcement of fishing regulations. Many fishers believe that they still follow the act’s significant laws and regulations while being involved in several destructive and prohibited fishing practices. There is a link between community awareness, the scope of the act’s provisions, the effectiveness of its enforcement, and the strength of its execution. One of the leading causes of biodiversity loss in the KL is inadequate and ineffective fishing regulations. Improvement in the enforcement of the fishing act may be the prominent option to ensure better biodiversity conservation and sustainable management of this wetland. This result calls for functional and policy attention to revising the regulations to account for socioeconomic and political elements contributing to environmental degradation. This study also highlights the urgent need for transdisciplinary collaboration initiatives and synchronous cooperation among the agencies in order to effectively implement the fishing laws and contribute to better conservation and sustainability of the Kaptai lake fisheries resources.

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Section: Discussionmentioning

confidence: 99%

Analyses of Protection and Conservation According to the Fish Act 1950 in Bangladesh’s Kaptai Lake Fisheries Management

Rayhan

Schneider

Islam

et al. 2021

Water

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“…Global population decline and isolation risks of river dolphins is frequently attributed to declining flows due to dams or barrages [11,16,18,32,43,44]. As a result, the need for adequate flow to conserve the remaining endangered river dolphins is heightened globally [10,19,20,44,45].…”

Section: Plos Onementioning

confidence: 99%

In-stream habitat availability for river dolphins in response to flow: Use of ecological integrity to manage river flows

et al. 2021

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Population decline and extinction risk of river dolphins are primarily associated with flow alteration. Previous studies predominantly highlighted maintenance of adequate flow for low water seasons when habitats contract and the risk of local extinction escalates. Although river dolphins are sensitive to reduction in river flow, no studies quantify the relationships between flow and ecology of river dolphins to mitigate the potential adverse impacts of flow alteration. We quantify the relationships between flow and the ecology of river cetaceans concerning Ganges River dolphins (GRD; Platanista gangetica gangetica) usable area availability (AWS) for the low water season at wider flows (50–575 m3/s) at finer spatial and temporal scales. This study reveals that distribution of area usable to GRD is highly regulated by the adequate flow and river attributes (velocity and depth) interactions that likely offer energetically efficient modes of locomotion to GRD, suggesting the hydro-physical environment as a major determinant of river dolphin distribution and abundance. Flow and AWS relationships indicate that the flow during the dry season negatively contributed to AWS, whereas that of pre-monsoon maximized the AWS, suggesting that modifying flow regimes does alter in-stream habitats at varying spatial scales and may influence life-history strategies. Substantial fragmentation in suitable pool availability and loss of longitudinal connectivity exhibited by dry season flow suggested a higher risk of adverse biological effects during the dry season, which may reduce population viability by reducing survivorship and reproduction failure. Owing to river dolphins’ dependence on the attribute of freshwater flow, they can be expected to be more affected by flow regulations as interactive effects. Considering the seasonal effects and changes in the availability of usable areas by flow alteration, adopting effective habitat retention plans by water-based development projects appears critical to avoid further ecological risks in aquatic species conservation. Identifying priority riverscapes for river cetaceans and prioritizing investment opportunities is an essential first step towards effective riverine cetacean conservation.

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“…Global population decline and isolation risks of riverine cetaceans is frequently attributed to declining flows due to dams or barrages [16,32,18,41,42,11]. As a result, the need for adequate flow to conserve the remaining endangered riverine cetaceans is heightened globally [19,20,43,42,10].…”

Section: Interactive Effects Of Velocity and Depth On Area-weighted Smentioning

confidence: 99%

In-stream habitat availability for river dolphins in response to flow: use of ecological integrity to manage river flows

Paudel

Koprowski

Thakuri

et al. 2020

Preprint

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Population decline and extinction risk of riverine cetaceans are primarily associated with flow alteration. Previous studies predominantly highlighted maintenance of adequate flow for low water seasons when habitats contract and the risk of local extinction escalates. Although riverine cetaceans are sensitive to reduction in river flow, no studies quantify the relationships between flow and ecology of riverine cetaceans to mitigate the potential adverse impacts of flow alteration. We quantify the relationships between flow and the ecology of river cetaceans with reference to Ganges River dolphins (GRD; Platanista gangetica gangetica) usable area availability (AWS) for the low water season at wider flows (50-575 m3/s) at finer spatial and temporal scales. This study reveals that distribution of usable area to GRD highly regulated by the adequate flow level as the interaction of appropriate velocity and depth at particular geomorphic that likely offer energetically efficient modes of locomotion to increase surfacing behavior efficiency, suggesting the hydro-physical environment as a major determinant of river cetaceans distribution and abundance. Flow and AWS relationships indicate that the flow during dry season negatively contributed to AWS, whereas that of pre-monsoon maximized the AWS, suggesting that modifying flow regimes does alter in-stream habitats at varying spatial scales and may influence life-history strategies. Substantial fragmentation in suitable pool availability and loss of longitudinal connectivity exhibited by dry season flow suggested a higher risk of adverse biological effects during the dry season, which may reduce population viability by reducing survivorship and reproduction failure. Owing to riverine cetaceans’ dependence on the attribute of freshwater flow, they can be expected to be more affected by flow regulations as interactive effects. Considering the seasonal effects and changes in the availability of usable areas by flow alteration, adopting effective habitat retention plans by water-based development projects appears critical to avoid further ecological risks in aquatic species conservation. Identifying priority riverscapes for river cetaceans and prioritizing investment opportunities is an essential first step towards effective riverine cetacean conservation.

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The endangered Ganges river dolphin heads towards local extinction in the Barak river system of Assam, India: A plea for conservation

Cited by 17 publications

References 25 publications

Analyses of Protection and Conservation According to the Fish Act 1950 in Bangladesh’s Kaptai Lake Fisheries Management

Analyses of Protection and Conservation According to the Fish Act 1950 in Bangladesh’s Kaptai Lake Fisheries Management

In-stream habitat availability for river dolphins in response to flow: Use of ecological integrity to manage river flows

In-stream habitat availability for river dolphins in response to flow: use of ecological integrity to manage river flows

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