Interview conducted by Advaith Jaikumar
Today, we had the pleasure of speaking with Dr. Elrika D'Souza, an esteemed expert in marine biology and a passionate advocate for preserving seagrass ecosystems and the remarkable dugongs that inhabit them. She works with the Nature Conservation Foundation as the Programme Manager of the Oceans and Coasts programme. With her extensive research experience and dedication to understanding plant-animal interactions in seagrass ecosystems, Dr. D'Souza has made significant contributions to the field of marine conservation.
May 28th marks World Dugong Day, a global event dedicated to raising awareness about the conservation of dugongs and their fragile habitats. This annual celebration aims to shed light on these gentle marine mammals' unique challenges and foster a deeper interest and commitment to their protection. In line with this occasion, we spoke to Dr. Elrika D'Souza today to share her insights and expertise on all things dugong!
1. What initially sparked your interest in studying marine ecosystems and specifically focusing on the conservation of dugongs?
My interest in studying marine ecosystems and focusing on the conservation of dugongs was initially sparked during my school years. I had always been fascinated by the underwater world and ocean life.
During my master's degree, I studied about dugongs in my academic courses, and while I had never seen one in person, the elusive nature of these marine mammals intrigued me.
I had the opportunity to work in the Andaman Islands, where I studied the status of corals. During my stay and research there, I became aware of the presence of dugongs in the area.
To my surprise, I discovered that no one had conducted extensive research on dugongs in the Andaman Islands. Not much was known about their population, behaviour, and habitat in the region. This knowledge gap piqued my curiosity even further and motivated me to focus my efforts on studying and conserving dugongs.
Three years after the 2004 tsunami, I finally had the opportunity to come back and research more about dugongs in their natural habitat. It was a transformative experience to witness these magnificent creatures grazing on seagrass meadows and observe their unique behaviours.
2. Have you encountered any unexpected or surprising findings during your research on dugongs and seagrass ecosystems that have challenged existing theories or shed new light on their ecology?
Most existing research on dugongs had been conducted in the waters of Australia or the Arabian Gulf, where larger herds with hundreds of dugongs are typically found. In contrast, the Andaman waters presented a relatively new field of research for studying dugongs. Here, we discovered that the population of dugongs was not as dense, and they were found in smaller herds of few animals rather than large herds.
Dugongs in the Andamans were primarily concentrated in areas with a cluster seagrass meadows. These seagrass meadows served as their feeding grounds, and we observed that dugongs would repeatedly graze in the same meadows.
We also found that the seagrass meadows in the Andaman waters were relatively low in numbers or smaller in size compared to other regions. Despite this, dugongs continued to rely on these meadows for their sustenance, and they could persist in areas with limited seagrass resources by repeatedly using the available patches.
3. Based on your research, what factors have contributed to the historical declines in dugong populations in the Andaman and Nicobar archipelago?
The primary factor is net entanglement, which has resulted in significant mortality among dugongs. These marine mammals can become entangled in fishing nets, leading to injury or drowning, ultimately affecting their survival. While occurrences of hunting have been reported, they appear to be relatively infrequent and not a widespread practice.
Interestingly, seagrass availability does not seem to be a significant reason for the decline in dugong populations. Seagrass meadows in the region are dynamic and have the ability to recover quickly from issues such as cyclones or from the feeding of dugongs.
Dugongs have preferred seagrass species, but they have been observed to adapt and consume other seagrass species when their preferred ones are unavailable. Hence, the decline in dugong populations cannot be attributed to a lack of seagrass resources.
4. Could you share some insights into the behavioural adaptations or alterations you have observed in dugongs in response to disturbances in their habitats?
Some behavioural adaptations that I have observed in dugongs include natural and human activity-related disturbances. Natural disturbances are common and can include cyclones, tsunamis, etc. Noise-related disturbances caused by human activities, such as boat traffic, jet skis, and tourist activities, have also influenced the behaviour of dugongs. In areas with increased human activity and noise in the waters, dugongs have exhibited noticeable changes in their feeding habits. While they would feed in certain areas during the day, with the rise in human activity, they have shifted their feeding behaviour to nighttime when disturbances and noise levels are generally reduced. This alteration in their feeding patterns allows them to avoid areas with higher human activity.
As mentioned earlier, the availability of preferred seagrass species plays a role in the behavioural adaptations of dugongs. Dugongs have specific preferences for certain seagrass species. However, when their preferred seagrass species are unavailable, dugongs select and consume alternative seagrass species or algae which might be less preferred.
5. In your post-doctoral research, you studied how seagrass species composition, sedimentation, and large herbivores affect blue carbon reserves in seagrass meadows. Could you explain the significance of blue carbon and its role in climate change mitigation?
Blue carbon refers to the carbon stored in coastal and marine ecosystems. It plays a significant role in climate change mitigation by acting as a carbon sink, absorbing and storing carbon dioxide (CO2) from the atmosphere. As human activities continue to increase CO2 levels, blue carbon ecosystems play a crucial role in trapping and sequestering more carbon than even terrestrial systems.
The majority of blue carbon is stored in the sediments beneath seagrass meadows. However, disturbances such as rising water temperatures, cyclones, storms, and habitat loss can affect the ability of these ecosystems to sequester carbon. When these systems are lost, the carbon that was previously trapped in the sediment can escape back into the atmosphere, contributing to further CO2 emissions.
While researchers believe mangrove systems may trap more carbon than seagrass meadows, it is important to recognize the significance of all blue carbon ecosystems and its combined effect. Any loss or degradation of these systems would release entrapped carbon, thereby exacerbating climate change.
6. What innovative conservation strategies have been implemented or proposed to restore seagrasses in the Andaman and Nicobar, and Lakshadweep archipelagos, and how do you envision these seagrass insurance sites aiding in the recovery of seagrass ecosystems?
A: In the Andaman and Nicobar archipelago, we have been exploring innovative conservation strategies to enhance dugong habitats. One of the key approaches involves fostering relationships with local communities and engaging them in conservation efforts. By collaborating with fishermen and communities, we aim to create safer environments for dugongs. This includes encouraging practices such as avoiding the use of gill nets, reducing boat speeds or staying away from areas inhabited by dugongs, and raising awareness about the impacts of tourism and fishing activities on dugong activity. The active involvement of people in these regions can significantly contribute to the recovery and well-being of dugongs by providing them with better feeding grounds and reducing threats.
In the Lakshadweep archipelago, the focus has been on conserving seagrasses that have been over grazed by green sea turtles. We have been exploring the idea of seagrass insurance sites in the lagoons of the islands. These sites serve as refuges for various organisms, including seagrasses, and act as insurance policies to safeguard their populations. By creating these seagrass insurance sites, we can enhance the recovery and protection of seagrass ecosystems, benefiting not only green sea turtles but also the many other organisms dependent on these habitats.
7. Have you noticed any cultural representations of dugongs among local coastal communities?
A: Yes, among both indigenous and settler communities, there are cultural representations of dugongs. For example, in certain tribes of the Andaman Islands, dugong hunting played a significant role in their history and prosperity. Although hunting is now prohibited, these tribes still hold cultural significance for dugongs. Some communities collect dugong bones, and the tusk is used for medicinal purposes or as an ornament. While hunting has decreased, these cultural connections with dugongs still exist.
8. Considering the interconnectedness of marine ecosystems, how do you believe the conservation of seagrasses and dugongs contributes to the broader goal of marine biodiversity preservation?
A: Seagrasses are often overlooked, yet they play a vital role in marine ecosystems. By conserving seagrasses and protecting dugongs, we indirectly contribute to preserving a large interconnected ecosystem. Seagrasses are crucial habitats and food sources for various organisms, including invertebrates, herbivorous fish, and green turtles. By safeguarding seagrass ecosystems, we create stable environments for these dependent species to thrive. Additionally, seagrasses help stabilise coastlines and improve water clarity by trapping sediments. Therefore, by conserving seagrass habitats and protecting dugongs, we contribute to the overall health and preservation of marine biodiversity.
9. How do you see the future of dugong conservation efforts, and what are the key challenges that need to be addressed to ensure the long-term survival of these remarkable marine mammals?
A: The future of dugong conservation efforts is multifaceted and varies across different regions. In places like the Andaman Islands, one of the key challenges lies in infrastructure development proposals that often overlook the importance of marine ecosystems. Raising awareness and initiating conversations are crucial to ensure long-term survival before implementing any changes that may adversely affect dugongs and their habitats. Researchers, conservationists, and government bodies must collaborate and have open dialogues to find sustainable solutions. It's important to remember that dugongs are slow-breeding species, with a single calf born every five to seven years. Therefore, even under the best circumstances, recovery will take time. However, if all threats are significantly reduced, there is still hope for their long-term survival, albeit with patience and dedicated efforts.
10. Could you share a favourite anecdote or encounter with a dugong? Something that left a lasting impression on you?
A: During the first few years of my research, I hoped to encounter as many dugongs as possible. However, one particular dugong stood out among all the others. It was incredibly accustomed to human presence, displaying an unparalleled level of comfort. People often went on swims with this dugong, and it seemed almost as if it was curious about our presence. What struck me the most was the combination of its calm demeanour and the underlying sense of hyperawareness that I had around it, which comes with being in the presence of a wild animal in such an open space. I would remind myself of the dugong's docile nature and this left an indelible mark on my memory.
Interestingly, much later, I had another encounter with the same dugong. I had grown tired on this occasion and was returning when I noticed it following me. We ended up in very shallow waters, and even at that moment, the dugong's unwavering gaze was fixed upon us as it continued to swim alongside. There was a close call when it almost collided with a coral, but its captivating gaze remained focused. The memory of that dugong, staring at us with such curiosity and connection, is something I will never forget.
As we commemorate World Dugong Day, it becomes ever more crucial to raise awareness and take action to protect these remarkable marine mammals and their fragile habitats. Dr. D'Souza's invaluable expertise has provided us with a deeper understanding of the challenges faced by dugongs and the potential avenues for their long-term survival. It is through collaborations between researchers, governments, and local communities that we can pave the way for a brighter future for dugongs, ensuring their continued presence and the preservation of the delicate seagrass ecosystems they call home.