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Inland fisheries in South and Southeast Asia represent important sources of food, and many are extensively stocked. Stocking often catalyses wider changes in inland fisheries is considered in this context. Stocking can be beneficial, providing additional sources of food, incentives to manage, and income‐generating opportunities. However, there are also identifiable risks: stocking can be used to avoid or ignore addressing reasons underlying the degradation of inland fisheries and economic development, tenure arrangements, and culture technologies involved in stocking can combine to transform the very nature of inland fisheries. These transformations can degrade environments and alter the nature and distribution of benefits, potentially marginalising and impoverishing fishers. There is consequently a need to consider and assess more explicitly in advance the implications of stocking for the nature and distribution of social and environmental costs and benefits, and the risks related to access to, and availability of, food. [ABSTRACT FROM AUTHOR]

Predictable aggregations of large marine mammals are valuable conservation targets, but aggregated populations can also be exposed to site‐level threats.The globally vulnerable Dugong dugon has a wide distribution but is found in large numbers mainly in Australia and the Arabian Gulf. Though Australian dugong populations are well studied, much less is known of the dugongs in the Arabian Gulf.The spatial and temporal persistence of dugongs around Bahrain, with a focus on large dugong groups (>50 dugongs), was determined using an occupancy modelling framework supported by historical records, structured interviews, citizen science network reports, and small‐scale boat and unmanned aerial vehicle surveys.Historical records and current distributional studies confirmed that large dugong groups have been reliably sighted around Hawar Island (Bahrain) since at least 1986, forming large, clumped groups that persist almost year round. The largest recorded so far in the world, these fluid groups (maximum of ~700 dugongs) account for ~60% of the dugongs found in Bahrain and ~12% of all dugongs in the Arabian Gulf.The delineated occupancy core area of large dugong groups (~145 km2) straddles the Bahrain–Qatar border, reflecting the transboundary nature of these groups.Careful management of human‐induced stressors (in particular, fishing, boating, and coastal development) combined with regular monitoring of Hawar Island's large dugong groups and their seagrass habitat is critical to safeguard this globally important population.The effectiveness of any conservation management is predicated on strengthening cooperation among all range states in the Arabian Gulf. A key recommendation of this study is to establish a regional network of marine protected areas encompassing core aggregation sites for dugongs, particularly the Hawar Islands in Bahrain, the north‐western waters of Qatar, Marawah Island in the United Arab Emirates in addition to the shallow waters between Saudi Arabia, Qatar, and United Arab Emirates. [ABSTRACT FROM AUTHOR]

Modification of river flows by dams and barrages has fragmented riverine habitats and threatened the survival of Indian subcontinental river dolphins.In this study, habitat use by endangered Ganges river dolphins in response to dry‐season operations (December‐March) of the Farakka barrage on the Ganga River, located about 20 km upstream of the India–Bangladesh border, was assessed.Ten surveys were conducted in: (i) the Ganga River below the barrage, where rapid changes in water levels were expected owing to barrage operations; (ii) the Farakka feeder canal with stable water levels; and (iii) the Hooghly River downstream of the canal. Dolphin distribution, water depth, fishing boat count and temperature were recorded in all surveys and the data were analysed in a dynamic occupancy modelling framework. Temporal trends in river discharge, primary productivity and fish availability were also estimated to explain river dolphin responses.Occupancy and colonization by dolphins increased in all stretches by spring/March, correlated with rising water temperature and increased fishing intensity, which was related to upstream migration of hilsa fish. In the Ganga River, dolphin occupancy in deep river pools remained stable, but resulted in increased overlap with fisheries as river flow declined. The feeder canal, with stable flows, witnessed increased colonization by dolphins, but also greater risk of bycatch in fishing nets. The canal that appeared as a hydrological refuge thus became an 'ecological trap'.The findings highlight the need for integration of flow maintenance and fishery regulations in the monitoring and management of canals as effective refuges for riverine species. We advocate the inclusion of ecological flow criteria and fishery regulations to reduce dolphin bycatch mortality, in the context of establishing river dolphin conservation plans and transboundary water‐sharing guidelines. The revision of the India–Bangladesh water‐sharing treaty in 2026 could incorporate the above considerations. [ABSTRACT FROM AUTHOR]

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]

Abstract: Small hydropower projects (SHPs) are promoted as environmentally benign alternatives to larger dams; however, the impacts of SHPs have been poorly studied, especially in tropical developing countries, where their growth is being encouraged. This study assessed the impacts of two SHPs on freshwater fish communities in the Western Ghats biodiversity hotspot of India. Two dammed and one undammed tributary of the Netravathi River, having similar stream order, elevation, and surrounding land‐use types, were identified as test and control sites respectively. Stream geometry, water chemistry, and fish assemblages were compared across upstream, dewatered, and downstream location categories within and across the three streams. Flow alterations induced by SHPs affected the dewatered river stretches most severely. Stream wetted width and depths diminished drastically in dammed dewatered segments, and consequently this region was characterized by elevated water temperature and reduced dissolved oxygen. Fish species composition varied significantly between dammed and undammed sites, across the upstream, dewatered, and downstream location categories. Dammed segments had lower fish species richness, diversity, and endemicity, and were dominated by eurytopic species (adapted to lentic conditions), unlike the control site, which was dominated by rheophilic species (adapted to flowing waters). Regression analyses indicated that fish species richness in dammed streams increased with distance from the dam in the upstream direction. The SHPs were found to have severe impacts on stream geometry, water chemistry, and aquatic biota, especially in the dry season. Given the ambitious targets of planned SHP growth, most of which are within ecologically fragile regions, changes in SHP operations and policies are proposed to enable the conservation of river fish diversity. These include mandatory environmental impact assessments, conserving undammed headwater streams in regulated basins, maintaining adequate environmental flows, and implementing other mitigation measures. [ABSTRACT FROM AUTHOR]

Abstract: Limited visual perception in aquatic environments has driven the evolution of diverse sensory modalities in aquatic mammals. Dolphins largely use echolocation for prey capture in the face of limited visual and olfactory cues. Multiple foraging modes exist, although an understanding of how sensory systems are adapted to environmental and prey characteristics is limited. This is especially true for animals with extreme sensory specialisation, such as South Asian river dolphins of the genus Platanista. This taxon is effectively blind and retains plesiomorphic traits from its once‐diverse ancestors. Distributed in murky rivers of the Indus‐Ganga‐Brahmaputra basins, it is thought to use mainly echolocation for feeding on fish and shrimp. We hypothesised that foraging modes used by Platanista differ according to prey position in the water column (at the river surface, mid‐column, and bottom) and are mediated by ecomorphology, acoustics, prey characteristics, and habitat features. To test this, we combined a detailed review of the literature (anatomy–physiology–morphology studies, observations in captivity) with preliminary field observations and acoustics studies to investigate foraging mode selection. Platanista displays peculiar foraging and feeding behaviours, including side swimming, rotational feeding, and grasp‐suction feeding. Feeding is restricted to small prey with low body depth. At the river surface and bottom, echolocation‐based foraging may not be efficient due to acoustic reflection or reverberation effects. Platanista uses echolocation clicks to scan and detect prey at distances of about 20 m across the river mid‐column, possibly switching to passive listening at the surface, and electroreception at the bottom, to maximise prey capture rate and feeding success. Platanista is remarkable for its ability to persist in some of the most intensively used and abused river basins of the world. Using echolocation, electroreception, and passive listening might reduce overall foraging costs and contribute to the adaptability of the taxon. [ABSTRACT FROM AUTHOR]

The Wroughton's free-tailed bat Otomops wroughtoni (Chiroptera: Molossidae) is a globally rare and data-deficient species. This species has been recorded only from four locations, in India and Cambodia, with the type locality in the Barapede caves, India. In this paper, we present an analysis of echolocation and social calls of O. wroughtoni from the Barapede caves. Echolocation calls of free-flying O. wroughtoni were narrowband and shallow frequency-modulated (shallow-FM), with peak frequency ranging between 14-17 kHz. Social call sequences of roosting O. wroughtoni showed five distinct signatures. Multivariate analyses of echolocation calls of O. wroughtoni and the other three molossid species found in India (Tadarida teniotis, T. aegyptiaca, Chaerephon plicatus), showed strong support for acoustic differentiation of these species. Our study will help identify probable occurrence of O. wroughtoni and the other species in unsurveyed areas through field acoustic surveys. It also proposes hypotheses about the ecology and foraging behaviour of O. wroughtoni that could be tested through further studies. [ABSTRACT FROM AUTHOR]