Coexistence of fisheries with river dolphin conservation

Kelkar, Nachiket, Krishnaswamy, Jagdish, Choudhary, Sunil, and Sutaria, Dipani (2010) Coexistence of fisheries with river dolphin conservation. Conservation Biology, 24 (4). pp. 1130-1140.

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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.

Item ID: 16902
Item Type: Article (Research - C1)
ISSN: 1523-1739
Keywords: alternative livelihoods; fisheries; fish-stock restoration; Ganges River dolphins; human-dominated river systems; resource competition; resource overlap
Date Deposited: 11 May 2011 00:23
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity @ 100%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8302 Fisheries - Wild Caught > 830299 Fisheries- Wild Caught not elsewhere classified @ 100%
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