Diving Deep with ROVs

In late August 2022, following the successful playtest of our board game on human-wildlife conflict, my colleagues and I embarked on another exciting journey. We travelled down south from Bangalore, to the coastal city of Pondicherry for a collaborative field expedition. Our mission was to assess the feasibility of using ROVs for surveying and data collection in deep sea. Over the next three days, we explored the capabilities of our SoFar Trident along India's east coast, venturing to depths of up to 30 metres.

ROVs, or remotely operated vehicles, offer a unique advantage by allowing underwater exploration in waters that may be hazardous for human divers. We got our SoFar Trident, named Varuna through the WCS Underwater Exploration Program. It can be operated via a mobile app, with information relayed through cables connecting the ROV when in action underwater. These cables facilitate the transmission of command and control signals, enabling remote navigation of the vehicle.

On the evening of day zero, our teams gathered from different cities. It was a mix of familiar faces and new introductions, as some team members who had previously interacted met in person for the first time. We discussed our aims for the coming days. Additionally, a few members who arrived early took the initiative to secure the boat for the next day and determine our exploration locations.

Day one kicked off with a delightful discussion over South Indian breakfast at a local restaurant. Following this, we headed to the harbour to test Varuna at the deepest accessible point from the coast. During the brief waiting period as the boat and captain conducted their checks, we did a quick inspection of the ROV and discussed the feasibility of mounting a waterproof action camera onto the external surface of the ROV.

We set out from the dock at 9am, but faced challenges once the boat was in the Bay of Bengal. The water away from the shore proved to be turbulent and the midday sun quickly wore us down. We made two successful launches to the water, amongst others. We were able to view the sea bed clearly in one of the instances, when we directed the ROV using our boat’s anchor as the guide. But the challenges took an intense turn for our crew. Despite their familiarity with boat operations and a lack of previous seasickness episodes, the combination of choppy seas and the immersive experience of monitoring the Trident's live-feed on a screen induced nausea and severe seasickness. Therefore, once we had gained a rough understanding of the conditions involving high current flow and low visibility at these depths, over a period of three hours in the water; we decided to return to shore.

Drawing from our past experiences with other Tridents, we are well aware of the paramount importance of regular motor maintenance to prevent corrosion, even when the Tridents were not actively used in the field. Consequently, our first task once on land was to clean the motors and external body of the Trident with fresh water.

We spent the following hours recovering from the first half’s experience by consuming lunch and coconut water. In the latter part of the day, we tried testing by adding a payload to our ROV, specifically mounting an external camera. We wanted to assess conditions related to depth pressure, visibility, and camera housing. Initially, we utilised scuba divers’ tanks available at a local dive training facility for our tests. However, we encountered limitations due to the size of the tanks. Subsequently, following a suggestion from the trainers, we shifted our testing to a nearby swimming pool. The pool’s management allowed us to use their facilities for a fee, helping with our trials.

Testing the ROV with additional payload.

On the following day, we were better equipped to handle the now-familiar conditions of the field site. Armed with Avomine, we commenced our day an hour earlier than the previous day, affording us a total of four hours in open water. The ingestion of the anti-nausea medication proved highly effective, preventing any further episodes of seasickness and enabling the successful operation of the ROV. Our improved situation allowed us to deploy the ROV to even greater depths greater than 20m, broadening our exploration to new sites. Upon returning to shore, we fixed on our plans for the next day, which included simultaneous dives using the trident as well as a diver.

Spotting a Moray eel through the ROV.

The final day of our expedition proved to be the most eventful. During one of the deployments, we had one of our colleagues dive alongside the ROV. Their role was to guide the ROV away from the boat's anchor rope to prevent any entanglement and ensure a faster, precise ascent to the ideal location. These dives occurred in two distinct locations, with one of the sites known for its rich underwater life presence. The live feed from the ROV, which captured a diverse array of species, including lion's mane fish, moray eels, starfish, and more, generated contagious excitement among the team. Additionally, we strategically placed markers on the ocean floor to assess visibility and made an attempt mimicking a transect survey with the assistance of an underwater camera and a diver.

This mission has enhanced our understanding of the capabilities and limitations of marine robot technology for conservation research. The Trident’s capability shone when it employed its exploration mode. It was swift to respond to controls and was able to accommodate additional payloads through its mounting system. However, it falls short in conditions of low visibility and fast-moving currents, making it less suitable for missions requiring repetitive activities such as transects or seabed mapping.

We have also effectively acquired three hours of deep-water footage (exceeding 25 metres) that includes a record of marine biodiversity along India's east coast. This achievement was made possible by deploying the Trident, which navigated through changing currents and varying visibility conditions. Furthermore, this mission allowed us to assess the viability of the Trident ROV in real-world conditions, providing valuable insights into future research possibilities.

From Drones to Dolphins

Nandini’s eyes light up every time she spots a dolphin surface on the screen. The mobile screen displaying the live feed from the drone currently hovering above the river’s surface - recording a pod of feeding Ganges river dolphins. Metres away from the shallow pool lies a gharial, India’s rarest crocodilian, basking in the evening sun on a sandbar. The team and I are currently on the banks of the river Gandak, a tributary of the river Ganga that flows through West Champaran district of Bihar. We are nearing the end of the day and the first of two field trips to develop systems for conservation and monitoring endangered river dolphins and gharials in regulated rivers of India’s Gangetic plains.

Drone pilot Nandini Mehrotra (centre) monitoring dolphin behaviour through the drone’s controller.

Ganges river dolphins (GRDs), as their name suggests are endemic to the Indo-Gangetic Basin. They are frequently spotted alone or in small groups, and typically a mother and calf travel together.¹ They are essentially blind hunters who use ultrasonic sound waves to detect fish and other prey.² Like most cetaceans, GRDs spend much of their time underwater, surfacing briefly to breathe.³ The movement of these animals is now known from observation to follow seasonal patterns, moving upstream when the water level rises before entering smaller streams. Due to the same —short glimpses of their presence above water and an inability to record their presence underneath because of turbid conditions that make camera entrapment impossible—monitoring their presence and mobility is difficult.

Historically, the rivers of Bangladesh, Bhutan, India, Myanmar, Nepal, and Pakistan were all included in the gharial’s habitat range.⁴ Today, its range is restricted to a few big rivers in India, Nepal, and Bhutan. It is easily identified from other crocodiles because of the adult male’s long and slender snout resembling the Ghara (a type of earthen pot used for storing drinking water).⁴ The gharial, a keystone species for the health of freshwater systems, works as do other crocodile species to move nutrients from the riverbed to the surface, boosting fish populations and assisting in the maintenance of the aquatic ecosystem. Gharials are cold-blooded creatures that emerge from underwater to bask themselves in the sun in order to regulate their body temperature or, nest.⁵ As the mud on their bodies dries, they blend in with the sandbars they bask in and are easy to overlook in their environment.

Ganges river dolphin (Platanista gangetica) and the gharial (Gavialis gangeticus) are both listed in the IUCN’s Red List as Endangered species and Critically Endangered species, respectively. Among the main causes of the Ganges river dolphins' (GRD) population decline in their range are poaching, becoming fishery bycatch, the construction of flood-control infrastructure, embankments, the presence of motorboats, dredging, siltation, progressive habitat degradation by sluice gates, and aquatic pollution.⁶ Adult gharial population nosedived from an estimated 436 adult gharials in 1997 to fewer than 250 mature individuals in 2006.⁷ Reasons for their decline can be cited to the increased use of gill nets for fishing in gharial habitat and the loss of riverine habitat as dams, barrages, irrigation canals and artificial embankments being built. Siltation and sand-mining further change the river courses; land near rivers being used for agriculture and grazing by livestock during the dry-season. Another reason for the decline has been attributed to over-hunting for skins and trophies, egg collection for consumption, killing for indigenous medicine and excessive and irreversible loss of the species habitat.⁸

A gharial (Gavialis gangeticus) basking with open jaws—a sign of relaxation—in the Gandak River.

The Gandak plays host to the second largest population of the critically endangered gharials in the country and is a significant habitat range to the migratory Ganges river dolphins. The riverine habitats of both species are threatened by water flow regulation by dams and barrages in this region. In regulated rivers, water level is determined by human needs- to meet various domestic and industrial demands for water or for flood control and drainage. Though we have relied on simple forms of river regulation to provide water security from early river valley civilizations, river regulation today is an important tool for socioeconomic development. Local controls are now replaced by the coordinated regulation of flows throughout entire river basins and large-scale water transfers from wet to dry regions via sluice gates and barrages. 

Reduced water flow leads to a reduction in foraging grounds and habitat. Dry-season flow regulation leads to sudden changes in depth, water temperatures, and bank erosion. This leaves GRDs at risk of being stranded in shallow river channels. Gharials may face breeding failures with unexpected water release that may wash away eggs. Such serious impacts need to be better understood to be addressed. Changes in dry-season river flow regulation are unpredictable and large-scale, making high-resolution data collection to monitor the species’ habitat in real-time indispensable. Such methods could enable swift communication of risks resulting from dam operations, to concerned water management authorities facilitating quick response to minimise mortality or injury risk to river dolphins or gharials, and eventually help inform ecologically oriented management of rivers. Despite a significant increase in awareness about river conservation, water management paradigms have not been able to address threats to species from dry-season river flow changes.

Spotter in the kayak on the River Gandak as observed from the survey boat.

The project's goal is to better understand these species and their conservation needs by using multiple methods in tandem and hence addressing previous knowledge gaps. It will be essential to continue extrapolating from real-time monitoring for prompt conservation action and efficient management of both human and ecological requirements. 

The first task between the collaborating team members from Wildlife Conservation Trust (WCT) and Technology for Wildlife Foundation (TfW) was to identify an appropriate field-site for study. The field site requirement was an area suitable to conduct study by air, water and land. Proof of abundance was to be obtained in land by visual bank-based surveys and in air by the use of UAVs in the area of interest. Attached to the boat as part of the boat-based methods was the CPOD (Cetacean and Porpoise Detection) device. It was used to collect data on GRDs’ frequencies, sound pressure levels, and general activity in the study area. To narrow down the field of study the team conducted a river survey in a zigzag transect, using a boat and kayak over the area of interest. The kayak was manned by a spotter and a kayaker, while the boat carried the rest of the team, following behind the kayak. 

Once the field of study was determined, the teams split into three. The first team worked on setting up and retrieving information from the CPOD and surveying dolphin presence and activity. The second team worked on tracking gharial abundance in the area of interest and its fringes. The last team ran aerial transects simultaneously over the same area, whilst coordinating over the radio. As such, valuable proof of record was gathered on the focus species over the duration of the field trip. 

References:

1. Ganges River Dolphin | Freshwater Dolphin | Species | WWF

2. Ganges River dolphins strongly alter their acoustic behaviour in response to underwater noise, finds study from India - Dr. Nachiket Kelkar

3. Surfacing and diving behaviour of free-ranging Ganges river dolphin, Platanista gangetica gangetica on JSTOR. (n.d.). www.jstor.org

4. The Gharial: Going Extinct Again1 | IGUANA • VOLUME 14, NUMBER 1 • MARCH 2007

5. Studies on the Indian Gharial | Journal of the Bombay Natural History Society

6. The endangered Ganges river dolphin heads towards local extinction in the Barak river system of Assam, India: A plea for conservation

7. Gharial: Threats | Wikipedia

8. Gharial-Gavialis gangeticus | IUCN Red List

Anatomy of an Unsuccessful Project: The Tiger and the Thermal Camera

Early in October, a former colleague and current field biologist with one of our NGO partners called me, and when I didn’t answer, sent me a message. “Hi. Trying to contact you for some help. Please call me when you are free”. It was Ashtami, the 8th day of Durga Puja, and I was on leave in Calcutta, visiting puja pandals across the city. We take our holidays at TfW quite seriously, and amidst all the festivities, unable and unwilling to take a call, I asked him to send me a voice note or an email.

The email arrived. “Hope this email finds you well. This is to inform you that a tiger has killed two people in Valmiki Tiger Reserve [The only Tiger Reserve in Bihar]. These incidents happened on the fringe area of forest and sugarcane fields. Bihar Forest Department is trying to capture this animal using box trap cages and chemical immobilization method. Forest department has placed rescue teams and also installed several trap cages. It's difficult to locate the animal in the sugarcane field. We would need a drone with IR/thermal camera to locate the animals. Is it possible for you to visit and assist the rescue team of the forest department in tracking and locating the tigers in the sugarcane field?”

This sort of request is familiar to us; we’ve managed field operations for a similar project in Uttar Pradesh in 2017, and know of numerous other similar projects across India. However, at this point in time, we do not own our own drone+thermal camera. Aside from the prohibitive cost (~INR 6 lakhs), our core function as an organisation is not to respond to emergencies, but to help our partners amplify their conservation impact. However, receiving this request almost made me feel guilty about not acquiring our own drone+thermal camera.

However, It turned out that there was already a drone + thermal camera in the field, but with some software issues. It was now Dashami, the final day of Durga Puja. I took some time out before the day started to provide trouble-shooting advice via text messages. I was later informed that they were not able to get this drone to work.

The next day, with both Durga Puja and my holidays over, another former colleague at the same organisation messaged me: “Can you help with drone services there or get someone else who can on an emergency basis.” The message continued with the news that a young girl had been killed that morning, and that it was only a matter of time before the Forest Department would need to shoot the tiger dead. Locating the tiger was of the utmost importance, either to tranquilise it or to kill it, ideally before it killed more people.

As part of India Flying Labs, and with links to the Drone Federation of India, we are embedded in India’s drone industry and have access to a large network of drone operators and manufacturers. I put the word out that there was an urgent conservation mission in rural Bihar that needed at least one drone + thermal camera as well as trained operators. In terms of work, this involved numerous phone calls, emails and text messages, as well as assessments on our part of how capable we felt a drone operator was of working on this particular project. I finally spoke to someone from an organisation who, in our opinion, had the capacity to help. I gave them the full project brief, and then connected them to my former colleagues. Later the same day, the tiger killed another person.

The next evening, when I called the field biologist to check on the situation and how he was, he said, “Not good”. The tiger had killed a mother and her pre-teen son early in the morning, and had been shot dead during a Forest Department operation in the afternoon. This particular tiger, designated a man-eater and posthumously identified as the three-year old male T104, had killed between 9 and 12 people (there are conflicting reports), with four confirmed kills in its last three days alive. The impact of his actions on Bihar’s tiger conservation efforts will manifest in the future, and they are unlikely to be positive in any way. It is unlikely that these recent events have helped convince local communities around Valmiki Tiger Reserve that tiger conservation is in their best interests.

I wasn’t in the field for this project; my role was purely to network and connect people who believed that they needed drone services urgently with those who would possibly be able to provide it. In the end, matters escalated rapidly, and concluded before additional resources were allocated. I’m too removed from the situation to assess whether a working drone + thermal camera would have helped locate the tiger earlier, preventing the later human deaths. The fact remains that we’ll never know; many people, and a tiger, are now dead.

Note: The email and text exchanges detailed have been edited to maintain the senders’ anonymity.