Abstract: Incidental mortality in fishing gear, especially gillnets, is considered among the most severe threats to the endangered Ganges River dolphin (Platanista gangetica gangetica). However, almost no information is available about actual interactions of the species with fisheries. An emaciated adult Ganges River dolphin was found stranded on Katka Beach where the eastern Sundarbans mangrove forest of Bangladesh meets the Bay of Bengal. The dolphin had a piece of fine-thread, mono-filament, 5-cm mesh-size gillnet, used to catch hilsa (Tenualosa ilisha) in large rivers and coastal areas, wrapped tightly around its rostrum. It also had a thicker strand, double-filament, 2.5- to 3.5-cm meshsize gillnet, used to catch medium-size fin fishes in large rivers and small creeks, entangled in its teeth at the end of the rostrum. The dolphin was disentangled and released. In another incident, the carcass of a nonlactating female Ganges River dolphin was also retrieved from a local fishing boat in the northeast portion of the Sundarbans. The dolphin had become entangled in a long-line fishing gear very similar to the rolling hooks used in the Yangtze River that have been cited as among the primary factors contributing to the probable extinction of the baiji (Lipotes vexillifer). These incidents confirm that Ganges River dolphins are vulnerable to being accidently killed by becoming entangled in gillnets and long-lines. These events also indicate the importance of monitoring mortality rates and establishing a protected area network in channel segments where the species occurs in relatively high numbers.
Key Words: Ganges River dolphin, Platanista gangetica gangetica, Irrawaddy dolphin, Orcaella brevirostris, gillnet, fishing gear entanglement, long-line, Sundarbans, Bangladesh
Document Type: Research article
Page Numbers: 362-366