Coexistence of Fisheries with River Dolphin Conservation |
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Authors: | NACHIKET KELKAR JAGDISH KRISHNASWAMY SUNIL CHOUDHARY DIPANI SUTARIA |
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Affiliation: | 1. Post‐graduate Program in Wildlife Biology and Conservation, Wildlife Conservation Society—India Program, National Centre for Biological Sciences, GKVK Campus, Bellary Road, Bangalore 560 065, India;2. Wildlife Conservation Society—India Program, Centre for Wildlife Studies, 12th Main, Banashankari, Bangalore 560 012, India;3. Ashoka Trust for Research in Ecology and the Environment, 659, 5th A Main, Hebbal, Bangalore 560 024, India;4. Vikramshila Biodiversity Research and Education Centre, T.M. Bhagalpur University, Bhagalpur 812 007, India;5. Office #207, School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia |
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Abstract: | Abstract: Freshwater biodiversity conservation is generally perceived to conflict with human use and extraction (e.g., fisheries). Overexploited fisheries upset the balance between local economic needs and endangered species’ conservation. We investigated resource competition between fisheries and Ganges river dolphins (Platanista gangetica gangetica) in a human‐dominated river system in India to assess the potential for their coexistence. We surveyed a 65‐km stretch of the lower Ganga River to assess habitat use by dolphins (encounter rates) and fishing activity (habitat preferences of fishers, intensity of net and boat use). Dolphin abundance in the main channel increased from 179 (SE 7) (mid dry season) to 270 (SE 8) (peak dry season), probably as a result of immigration from upstream tributaries. Dolphins preferred river channels with muddy, rocky substrates, and deep midchannel waters. These areas overlapped considerably with fishing areas. Sites with 2–6 boats/km (moderately fished) were more preferred by dolphins than sites with 8–55 boats/km (heavily fished). Estimated spatial (85%) and prey–resource overlap (75%) between fisheries and dolphins (chiefly predators of small fish) suggests a high level of competition between the two groups. A decrease in abundance of larger fish, indicated by the fact that small fish comprised 74% of the total caught, may have intensified the present competition. Dolphins seem resilient to changes in fish community structure and may persist in overfished rivers. Regulated fishing in dolphin hotspots and maintenance of adequate dry season flows can sustain dolphins in tributaries and reduce competition in the main river. Fish‐stock restoration and management, effective monitoring, curbing destructive fishing practices, secure tenure rights, and provision of alternative livelihoods for fishers may help reconcile conservation and local needs in overexploited river systems. |
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Keywords: | alternative livelihoods fisheries fish‐stock restoration Ganges River dolphins human‐dominated river systems resource competition resource overlap competencia por recursos delfines del Rí o Ganges formas de vida alternativas pesquerí as sistemas fluviales dominados por humanos restauració n de poblaciones de peces traslape de recursos |
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