Wildlife Week 2019: Maharashtra's humpback dolphins locked in battle for safe habitats and food security

"Gado asa ithe..."There are dolphins around here, said Suba, a gill net fisherman, as he scouted for a place to lay his gill net one late evening. As we went out further away from the shore in his boat, I could sense Suba’s annoyance. He was after a catch of bangda (mackerel) and saundala (false trevally)."The catch report is good today, I don’t want to lose my fish to anyone!", Suba said as we stopped to lay the net.The Indian Ocean's Humpback dolphins (Sousa plumbea) are called "Gada reda" in Malvan, situated in the coastal district of Sindhudurg in Maharashtra. The name loosely translates to 'the mad bull', for the brute strength and intelligence they exhibit breaking into fishing nets to steal a prized catch. Almost all the gill net fishermen in the coastal district of Sindhudurg have lost their fish catch, the structural integrity of their gill nets, or their entire fishing gear to humpback dolphins at least once in their lifetimes.[caption id="attachment_7446741" align="alignnone" width="1280"]

Two dolphins swimming in the ocean. image credit: Ketki Jog[/caption]

Human-Dolphin interactions

Tracing the oral history of these interactions, roughly over the past 50 years, reveals the nature of this relationship.  The attitudes of the fishermen towards dolphins and these interactions have changed from anger and hostility to annoyance and indifference. With mechanisation, mending or replacing nets has become easier, cheaper and less time-consuming.  In spite of the modernisation, however, gill net fishing has gone from operating in deeper (30-40 m depth) to largely shallow and near-shore waters (5-10 m).Fishery targets are shifting down the food chain as the populations of predators declines to below commercially viable numbers. The habitat and resource overlap between dolphins and fisheries are therefore becoming increasingly apparent, leading to a perceived increase in these interactions.[caption id="attachment_7446751" align="alignnone" width="1280"]

A fisherman casting their nets at sunset. image credit: Pixabay[/caption]The local narratives also offer a window into the ecology of the dolphins. As per the local knowledge, dolphins inhabited the estuarine areas, further upstream, until about 30 years ago. Many fishermen also believe that the resident humpback dolphin population has risen since the past few years. “They used to be right around the Devbag sangam (confluence). But there are so many boats in the water now. Too much noise and too little fish!”, said Sadand Tandel. “The moment we put our nets in the water, the dolphins come. It’s almost like they know what’s happening”, a gill net fisherman from Devbag recounted, “like they can tell the difference between the engine noise of a gillnetter and purse seiner too. They won’t go behind the purse seiner.”  While describing their own experiences with humpback dolphins, fishermen often anthropomorphised certain dolphin traits and behaviours. These anthropomorphic accounts point towards how these dolphins have adapted to their area over time and to the changes in their habitats. The human dimension could also be crucial in understanding the behavioural ecology of the dolphins during these interactions.

Effects of overfishing

The pressures of overfishing are now largely visible in Sindhudurg. As the fish catch declines, larger and once common fish species are slowly becoming a rarity. The decrease in the catch, however, has not translated into a decrease in demand. As a result, even large-scale fishing operations like purse seining (a net is tightened around a school of fish) and trawling have moved to inshore waters, in search of more fish. A shift in livelihoods from fishing to tourism is also imminent because of the dwindling profits.[caption id="attachment_7446731" align="alignnone" width="1280"]

Fishermen hard at work and a dolphin can be seen keeping an eye on its food. image credit: Ketki Jog[/caption]Since the past two years, it has become common practice for fishermen to be involved either part-time or full-time in tourism-related activities like recreational diving, boating, and water sports. Through these socio-economic shifts, the human-dolphin interactions will also likely increase. With diminishing, resources dolphins will be driven for their search of forage fish into the path of fishery operations. During our team’s surveys, we have witnessed large groups of humpback dolphins swimming around active fishing gear like gill nets and purse seines. Some of them show tell-tale signs of injuries due to gear, with deep cuts along the dorsal fins. Along the coast of Maharashtra, many reported dolphin strandings also show signs of emaciation and gear entanglements.

Conservation

These economic shifts could be a useful mechanism to shift the nature of these interactions. However, with rising pressures of coastal development on the dolphins' habitats, negative interactions with fisheries could possibly escalate negative human attitudes. Measures to reduce or counter these interactions could only prove superficial and insufficient without a wider look at the social-ecological drivers. In light of the impact of fishery interactions, in the form of bycatch and entanglements for the dolphins, and economic losses for the fishermen, place-based management could be a more effective conservation alternative.[caption id="attachment_7446781" align="alignnone" width="1280"]

Some dolphins have been spotted with cuts on their fins due to interactions with fishing nets. image credit: Ketki Jog[/caption]Studying both the human and animal aspects of these interactions will add to our understanding of this nuanced and complex relationship. It would be worthwhile to acknowledge that these interactions may never really cease to exist, but a thorough understanding of its intricacies will bring us closer to peaceful coexistence. Better communication and knowledge sharing among fishing communities and researchers will also be an important step in devising context-specific and integrative conservation measures.While sorting the catch after the fishing trip, Suba noticed ironically, a few plump mackerel and sardines with some missing juicy chunks of meat. “This is how I know those dolphins ate my fish”, he said, “pomfrets are their favourite”.The author is a doctoral candidate at James Cook University, Australia and is studying cetacean-fisheries interactions along the Sindhdurg coast of Maharashtra.