DHARWAD — The Arabian Sea, stretching along the 343-kilometer coastline of Karnataka, has long been celebrated for its rich biodiversity and its role as a primary economic engine for thousands of fishing families. However, beneath the azure waves and amidst the bustling activity of commercial ports, a silent crisis is unfolding. A landmark study by researchers from Karnatak University, Dharwad, has unveiled a grim reality: human activities, ranging from industrial fishing to heavy vessel traffic, are driving an unprecedented wave of marine mammal deaths.
Between July 2023 and September 2025, the research team documented a staggering 65 strandings of whales, dolphins, and porpoises across 39 different beaches. These findings, which establish a critical baseline for marine conservation in the region, suggest that the very waters these protected species rely on for survival have become ecological minefields.
The Magnitude of the Crisis: Main Findings
The study, led by scientists from the Department of Zoology at Karnatak University, represents one of the most comprehensive systematic efforts to track marine megafauna mortality in Indian history. Historically, records of stranded whales or dolphins in India were largely anecdotal, consisting of sporadic reports spanning the last two centuries. This new research shifts the paradigm toward a data-driven, long-term monitoring framework.
Of the 65 recorded strandings, the Indian Ocean humpback dolphin (Sousa plumbea) emerged as the most frequent victim, accounting for over 60% of the total cases. This species is particularly vulnerable due to its biological preference for shallow, nearshore waters—the same areas where human commercial activity is most concentrated. Other victims included the elusive, deep-water Cuvier’s beaked whale and various species of porpoises, all of which play vital roles as keystone species that regulate marine food webs and maintain the health of the ecosystem.
The researchers utilized kernel density analysis—a sophisticated geographic mapping tool—to identify "mortality hotspots." The data revealed that the southern districts of Udupi and Dakshina Kannada are the most dangerous zones for marine mammals, showing the highest concentration of strandings.
Chronology of the Research: A Two-Year Vigil
The study was not merely a retrospective analysis but a rigorous, boots-on-the-ground operation that lasted over 26 months.
- July 2023: The project commenced with the establishment of a 343-kilometre patrol route. Researchers began weekly transect surveys, often conducted on foot or via coastal roads, to ensure no stretch of the beach went unmonitored.
- Late 2023 – Early 2024: The team focused on building a "Rapid-Response Network." They collaborated with local fishing communities, non-governmental organizations (NGOs), and citizen scientists. This network proved essential, as it allowed for real-time reporting of carcasses before they could be washed back out to sea or scavenged.
- 2024 Monsoon Season: Researchers noted a significant spike in strandings during the pre-monsoon and monsoon months. This period coincides with shifting oceanographic currents and intense fishing pressure as vessels race to maximize catches before seasonal bans or during windows of fair weather.
- September 2025: The data collection phase concluded, followed by a comprehensive analysis of the necropsy reports and spatial data to finalize the study’s findings.
Throughout this period, whenever a carcass was located, the team coordinated with veterinarians authorized by the local Forest Department. These experts performed on-site post-mortem examinations, often under challenging conditions on remote beaches, to determine the "probable cause of death" (PCOD).
Supporting Data: The Anatomy of a Stranding
The forensic evidence gathered during the study provides a harrowing look at the physical toll human industry takes on marine life. The researchers categorized the causes of death into several primary drivers:
1. Fisheries Interactions and Bycatch
The most common cause of death was accidental entanglement in active fishing nets. Dolphins, being mammals, must surface to breathe. When they become entangled in heavy commercial nets, they are unable to reach the surface and eventually drown. Necropsies frequently revealed lungs filled with water, a definitive sign of drowning.
2. Vessel Strikes and Propeller Injuries
The Karnataka coast is a hub for both commercial shipping and mechanized fishing boats. Many carcasses bore the marks of violent encounters with these vessels. Researchers documented "blunt force trauma" consistent with high-speed vessel strikes and deep, rhythmic lacerations caused by boat propellers. In several cases, these injuries were so severe that they caused immediate death or led to fatal infections.
3. The "Ghost" Threat and Plastic Ingestion
Beyond active fishing, "ghost nets"—abandoned, lost, or discarded fishing gear—continue to fish indiscriminately for years. The study found animals entangled in these derelict nets. Furthermore, the internal examinations of several mammals revealed digestive tracts severely blocked by plastic debris. In a world where plastic pollution is ubiquitous, these apex predators often mistake floating plastic for prey, leading to slow starvation.
4. Seasonal and Geographic Correlation
The kernel density analysis showed a clear overlap between nutrient-rich upwelling zones—which attract fish and, subsequently, dolphins—and areas of high-intensity human activity. The concentration of deaths in Udupi and Dakshina Kannada suggests that the density of mechanized boats in these regions is a primary factor in the high mortality rate.
Official Responses and Collaborative Efforts
The research was made possible through a unique collaboration between academia and state authorities. The Karnataka Forest Department played a pivotal role, granting the necessary permissions for necropsies and providing logistical support.
"This study provides us with the ‘actionable intelligence’ we have lacked for decades," noted a representative involved in coastal conservation. "Previously, we knew animals were dying, but we didn’t have the spatial mapping to say where it was happening most or the forensic data to say why with such certainty."
Local fishing unions have also been engaged in the dialogue. While the fishing industry is often viewed as the antagonist in marine conservation stories, the researchers emphasized that many fishermen are willing to cooperate if provided with the right tools. The "Rapid-Response Network" relies heavily on the eyes and ears of the fishing community, who are often the first to see a stranded animal.
However, the report also highlighted significant hurdles. Nearly 50% of the strandings were classified as having an "unknown cause of death." This was primarily due to the advanced state of decomposition of the carcasses by the time they reached the shore. In the tropical heat of Karnataka, a carcass can become forensically unviable within 24 to 48 hours. Furthermore, the "true" death toll is almost certainly higher, as many animals that die at sea never wash ashore, instead sinking to the ocean floor or being carried away by deep-sea currents.
Implications for the Future: A Call for Sustainable Management
The findings from Karnatak University serve as an urgent warning that the current trajectory of coastal activity is unsustainable. The researchers have proposed several critical interventions to mitigate the crisis:
1. Gear Innovation: The introduction of bycatch-reduction devices and acoustic "pingers" on fishing nets could help warn dolphins away from active gear. Transitioning to more sustainable net materials that degrade more quickly if lost could also reduce the impact of ghost nets.
2. Vessel Traffic Regulation: Implementing "speed zones" in known marine mammal hotspots, particularly during the sensitive pre-monsoon seasons, could significantly reduce the incidence of fatal vessel strikes.
3. Marine Protected Areas (MPAs): The identification of hotspots in Udupi and Dakshina Kannada provides a roadmap for where the government might establish seasonal or permanent protected zones where certain types of high-impact fishing are restricted.
4. Enhanced Marine Forensics: To solve the problem of "unknown" causes of death, the researchers advocate for a more robustly funded necropsy program, including mobile refrigeration units that can preserve carcasses for more detailed laboratory analysis.
5. Plastic Mitigation: On a broader scale, the study reinforces the need for stringent plastic waste management in coastal towns to prevent the "silent killing" of marine life through ingestion.
Conclusion
The dolphins and whales of the Arabian Sea are more than just charismatic megafauna; they are indicators of the ocean’s overall health. Their presence ensures a balanced ecosystem that, in turn, supports the very fisheries that the human population depends on.
The work of the researchers at Karnatak University, Dharwad, has moved the conversation from anecdotal concern to scientific certainty. As the 2026 season approaches, the data is clear: without targeted intervention and a shift toward more conscious coastal management, the "shadows in the surf" may eventually disappear forever, leaving behind a sterile sea and a crippled blue economy. The survival of Karnataka’s marine heritage now rests in the hands of policymakers, who must decide if the price of progress is worth the silence of the sea.
