In the early 1980s, nearly 5,000 Gangetic river dolphins swam in India's river systems. Today, it is difficult to spot even one. The strange creatures, often called "blind dolphins" because their eyes lack lenses, are native to one of the most densely populated regions on the planet: they share their habitat with some 400 million humans.
To put that into perspective, every fish-seeking dolphin in the Gangese River Basin has roughly 220,000 human mouths to compete with for food. Those are tough odds, and they've pushed the species into rapid decline over the past century. But now a new survey – the largest ever conducted on dolphins in the area – suggests the animals may be holding up better than we thought.
The "My Ganga, My Dolphin" campaign, conducted by the World Wildlife Foundation (WWF) with the help of local fishing communities, has successfully surveyed a 3,350-kilometre stretch of India's Ganga River. It took 6,000 hours and involved 21 teams, but in the end 1,263 of the endangered dolphins were found – nearly twice the number reached in previous counts.
"It's not as simple as saying their numbers have doubled," cautions WWF India's Suresh Babu. In part, the jump can be chalked up to a larger survey area. "[But] it could be that in certain stretches [of the river] a breeding population has established itself," he says.
The survey results highlight interesting patterns that could help us protect these animals in the coming years. Because the dolphin is an indicator species, its health is a good reflection of the wellbeing of the entire river ecosystem.
"Some stretches of the river have reported an increase, while there has been a decrease in others. And the reasons [for that] need to be analysed," explains Babu. It's possible that areas with low dolphin counts are polluted or experiecing some kind of imbalance.
During the count, the team also interviewed local villagers to better understand the public's perception of their aquatic neighbours. By mapping the responses with the new population data, they'll be able to put critical education programmes in place.
"What needs to be realised is that there is a lot of connection that people in these habitats have with these animals," Babu told Scroll. "If they are not involved in conservation, I don’t see how it would work."
Listed as endangered on the IUCN Red List since 1996, the Gangetic dolphin (Platanista gangetica) remains mysterious not for lack of effort on the part of researchers, but because it's a notoriously difficult animal to study.
Unlike the dolphins we see in the open ocean, freshwater dolphins prefer to spend their time in the deepest parts of their habitat, using their flukes to trawl the muddy bottom for prey hiding in the sediment. This makes topside surveys particularly challenging: the only time you'll spot a river dolphin is when it comes up for a quick breath.
Though some protections are now in place, the few remaining Gangetic dolphins are still poached for their meat and oil, which are prized in traditional medicine and used as fishing bait. Entanglement in fishing gear and habitat disruption caused by irrigation canals and dam building are also major threats.
It takes females up to ten years to reach sexual maturity, and one calf is typically born only every two or three years, making the prospect of a thriving, breeding population particularly exciting for everyone involved in the survey.
This is only the first leg of an ongoing analysis of the larger Basin, and we don't have the full picture just yet, but Babu is encouraged by the success of the work thus far. "With this count, and data gathered from the community, we hope that a robust conservation strategy can be developed in the months to come," he says.
Top header image: WWF India