Ganges river dolphin tagged and released in Assam

Move aims to understand their seasonal and migratory patterns, habitat utilisation, particularly in fragmented or disturbed river systems

Guwahati: A male Ganges river dolphin in Assam was tagged and released with the aim to understand their seasonal and migratory patterns and habitat utilisation, particularly in fragmented or disturbed river systems.

The initiative has been conducted under the auspices of the Ministry of Environment, Forest and Climate Change (MoEFCC) and implemented by the Wildlife Institute of India (WII) in collaboration with the Assam Forest Department and biodiversity organisation Aaranyak, with funding from the National CAMPA Authority, according to a release.

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This is the first tagging of the species in India under Project Dolphin to undertake a comprehensive range-wide research to develop a conservation action plan, and fill existing knowledge gaps for the long-term conservation of the species, it said. The Ganges river dolphin, the national aquatic animal, is unique in its ecology, being nearly blind and relying on echo location for its biological needs.

Approximately 90 per cent of the species’ population resides in India, historically distributed across the Ganga-Brahmaputra-Meghna and Karnaphuli river systems. However, its distribution has drastically declined over the past century.

Despite its wide range, significant knowledge gaps remain regarding this species due to its elusive behaviour, it surfaces for only 5-30 seconds at a time, posing a significant challenge in understanding the ecological needs of the species and for any scientifically sound conservation interventions.

“Tagging river dolphins will contribute to evidence-based conservation strategies that are urgently needed for this species. I am delighted that this historic step has been undertaken”, Wildlife Institute of India (WII) Director Virendra R Tiwari said.

Project investigator Vishnupriya Kolipakam said this is a significant advancement in understanding the ecological needs of river dolphins, which will help conserve critical habitats within these vast river ecosystems. ‘This is vital not only for aquatic biodiversity but also for sustaining thousands of people who depend on these resources,” he said.

The tagging was made possible by advancements in technology, the lightweight tags emit signals compatible with Argos satellite systems even with limited surfacing time and are designed to minimize interference with dolphin movement. Plans are underway to extend this initiative to other states inhabited by Ganges river dolphins to build a comprehensive understanding of their population dynamics and habitat requirements.

Ganges river dolphins are apex predators and serve as umbrella species for the river systems, which makes it important to ensure their well-being, as it will ensure the sustenance of the entire river ecosystem. There is a paucity of information on Ganges river dolphin habitat needs, movement patterns or home-range information and it was decided to undertake satellite tagging of dolphins in its distribution range.