UAVs for Riverine Ecosystems

*Aerial view of braided channels in the Gandak River, April 2022. (© Technology for Wildlife Foundation)*

Ganges river dolphins and gharials are two iconic species endemic to the Indo-Gangetic Basin. The endangered Ganges river dolphin, largely blind, uses ultrasonic waves for navigation and hunting. As mammals, they surface briefly to breathe every 3-5 minutes. Documenting these dolphins is challenging due to their brief surface appearances and the murky waters they inhabit. Gharials, distinguishable by the male's long snout, are critically endangered with their population highly impacted by habitat loss.

In this project, we collaborated with the Wildlife Conservation Trust’s (WCT) Riverine Ecosystems and Livelihoods Programme. We studied the two species using a combination of techniques over two field trips to the the Gandak in 2022 and 2023. Simultaneously collecting data through UAVs, boat- based visual methods and acoustically through CPODs allowed us to test and compare which techniques were best suited for different aspects of understanding the two species. This enables us to plan more efficient and information-rich surveys for the future. This project has been summarized as a case study for WeRobotics as well as experiential blogs (1, 2, 3) by the TfW team.

Building on our learning there, we returned to the Ganges in 2024. In this project, we used UAVs to collect video footage of dolphins in pre-identified hotspots. This data has been analysed to estimate the size and body condition of individual dolphins, findings of which will be published. Details of the methods we used to be able to analyse dolphin size using drone footage have been summarised in our technical blogs (4, 5).

Aerial and boat-based survey methods being carried out in tandem by the WCT - TfW project team, April 2022. (© Nancy Alice/ Technology for Wildlife Foundation)

Drone pilot Nandini Mehrotra (centre) monitoring dolphin behaviour through the drone’s controller. (© Nancy Alice/ Technology for Wildlife Foundation)

Aerial group photograph of team members, April 2022. (© Shashank Srinivasan/ Technology for Wildlife Foundation)

Project team members launching a drone, April 2022. (© Nancy Alice/ Technology for Wildlife Foundation)

Project team members in action, April 2022. (© Nancy Alice/ Technology for Wildlife Foundation)

Tarun Nair conducting a visual survey, February 2023. (© Nancy Alice/ Technology for Wildlife Foundation)

TfW team members conducting a mapping mission from the banks of the River Gandak, February 2023. (© Nancy Alice/ Technology for Wildlife Foundation)

Project team members (L-R) Nandini Mehrotra, Dr. Nachiket Kelkar and Shashank Srinivasan in discussion, February 2023. (© Nancy Alice/ Technology for Wildlife Foundation)

Tarun Nair and Dr. Nachiket Kelkar conducting a visual survey, February 2023. (© Nancy Alice/ Technology for Wildlife Foundation)

Project team introducing Bihar Forest Department personnel to the use of UAVs for conservation. (© Nancy Alice/ Technology for Wildlife Foundation)

Group picture of project team in field, February 2023. (© Nancy Alice/ Technology for Wildlife Foundation)

Project teams from WCT and TfW in action, February 2024. (© Nancy Alice/ Technology for Wildlife Foundation)

Project team launching a drone from the banks, February 2024. (© Nancy Alice/ Technology for Wildlife Foundation)

(L-R) Dr. Nachiket Kelkar in dicussion with Nandini Mehrotra and Sravanthi Mopati, February 2024. (© Nancy Alice/ Technology for Wildlife Foundation)

(L-R) Ramya Roopa, Sravanthi Mopati, and Dr. Kadambari Despande conducting a visual survey, February 2024. (© Nancy Alice/ Technology for Wildlife Foundation)

Project team in action, February 2024. (© Nancy Alice/ Technology for Wildlife Foundation)

Group picture of the team members in the field, February 2024. (© Nancy Alice/ Technology for Wildlife Foundation)

Dolphin spotting from the river bank at Kahalgaon, Bihar. (© Nancy Alice/ Technology for Wildlife Foundation)

A single frame extracted from drone footage of a Ganges river dolphin surfacing, with zoomed inset of the same. (© Technology for Wildlife Foundation & Wildlife Conservation Trust)