- A recent study used reports from fishers, divers, Indian defence agencies and forest departments, over a five-year period, to monitor dugongs in the Andaman Islands.
- Dugong monitoring is challenging in areas such as the Andaman Islands. Citizen scientist and stakeholder networks are an effective and low-cost method for spotting dugong populations in such areas.
- Dugong populations have declined globally in recent decades due to habitat loss, bycatch, hunting and boat collisions and were believed to be locally extinct in Little Andamans island.
A citizen science network, created by scientists from the Wildlife Institute of India (WII), studied elusive dugongs in the waters of the Andaman Islands in a long-term monitoring stud over five years and found that dugongs are more common in the Islands than previously thought. Formed with stakeholders, including fishers, divers, Indian defence personnel and forest departments, the network reported on observations of dugong herds in the waters around the Andaman Islands between 2017 and 2022, as part of the long-term monitoring study.
Dugongs are one of the only four surviving species of the order Sirenia — a once diverse group of marine mammals that include manatees — and are found in the coastal waters of at least 39 countries in the Indo-Pacific region. Dugongs are categorised as vulnerable according to the International Union for the Conservation of Nature (IUCN) Red List.
Compared to other regions where the dugong is found, its population is low, with an estimated 250 in Indian waters. While there are known records of dugongs in the Andaman Islands, they are rarely spotted there.
Due to the island formation’s large size, relatively low dugong populations and the elusive nature of dugongs, traditional systematic surveys cannot reliably detect dugongs in the region. In this case, anecdotes from multi-stakeholder sea-farers represent a cost-effective method to fill the existing data gaps in dugong research, notes the study that was published in January this year.
The elusive dugong
Dugongs live in seagrass meadows found in warm shallow coastal waters, which are their sole food source. They are often found in herds that range widely in size from just a few members to hundreds based on food availability. While large herds and populations are common along the coasts of Australia and in the Arabian Gulf, they are rarely spotted in Indian waters. A 2016 report from the Wildlife Institute of India (WII) estimated the total dugong population in all Indian coastal waters was around 200 individuals.
This was not always the case, however. In this study, senior fishers reported sightings of herds from 40-50 years ago that were 15-20 individuals in size and a researcher interviewed in this study anecdotally reported commonly seeing herds of around 10 individuals in some parts of the Andaman Islands in the 1990s.
Seagrass meadows, however, are highly sensitive to severe weather events and human activities. Dredging, trawling, and runoff can significantly disrupt these ecosystems. The tsunami in 2004 disrupted seagrass meadows around Little Andaman, part of the Andaman Islands, so significantly, that dugongs were thought to be locally extinct.
The recent findings seem to indicate that dugong populations in the Andaman Islands are recovering. According to Kuppusamy Sivakumar, an author on the paper and researcher at WII, “I don’t expect bigger sized herds of dugongs in the Andaman and Nicobar Islands due to smaller sized seagrass meadows that won’t support larger herds. However, sightings of about 11 individuals in a herd in the Andaman waters itself is amazing.”
The authors reported 63 dugong herd sightings, ranging in size from three to 13 individuals, between 2017 and 2022, which is significantly higher than any report in recent decades. Further, calves were spotted in more than half of the herds observed which, according to Sivakumar, “is good news! A calf sighting is always good news.”
However, these results may not necessarily indicate a significant or long-term improvement in dugong conservation efforts. Sivakumar continued, “Dugongs are slow breeding animals and are critically endangered in India; therefore, any visible improvement in the population size may take time.”
Vardhan Patankar, a marine biologist who has worked extensively in the Andaman and Nicobar Islands, similarly cautioned, “It’s great that researchers were able to report a sighting of many calves; however, this number is extremely low compared to Arabian Gulf waters and Australia.” He continues, “Relatively high sightings of herds with mother-calf populations does not indicate that the population is stable or recovering. It’s just that due to technology and overall awareness, the reporting has increased in recent years.”
Citizen science networks
The large network of citizen scientists that the researchers managed to organise, made significant contributions to the study. On this point, Patankar noted, “Due to the vastness of the islands it is challenging to engage a population and one needs a strong rapport and network with communities.”
“Initially, it was a challenging task for us to bring all stakeholders on board,” Sivakumar explained. “At the beginning, we started with the Forest Department of Andaman & Nicobar Islands and then with other line departments such as Fisheries, Education, Tribal Welfare, Coast Guard, Navy, Marine Police, etc.”
“After getting the confidence of various governments departments, organisations, and NGOs, we approached the main stakeholders (i.e., fishing community and indigenous people). Thanks to my enthusiastic and dedicated students who have tirelessly conducted a series of sensitisation programs targeted, but not limited towards, sea-faring stakeholder agencies,” he added.
A major advantage of citizen science is that local communities often have knowledge and insights into the study system that researchers coming into that region are not aware of. Additionally, the process of developing citizen science networks and gathering data can improve awareness of conservation issues. Patankar describes citizen science as, “… a great educational tool, as it creates necessary interest and citizen scientists see the benefit of their data collection process.”
“Many people we interacted with initially, were not aware of the fact that dugongs are found in their neighbouring waters. Dugong being the state animal of the Andaman and Nicobar Islands, this state of knowledge was surprising.” said Sivakumar when asked about the overall attitude of stakeholders regarding dugongs at the beginning of their experiment.
He then described the changes he noticed as the experiment progressed. “Later, the same stakeholder groups started reporting dugong sightings to us and we felt an attitudinal change in terms of the magnitude with which the sightings were reported. Not just that, the word spread and more people whom we did not even meet or engage in our programs began to report dugong sightings. We thus, believe that engaging citizen scientists in research and conservation, is an efficient tool, as it is the first step towards sensitisation.”
Challenges with citizen science
While citizen science is a potentially useful and cost-effective tool, both for gathering data and educating the public, it does have its disadvantages. Creating and maintaining such a large and diverse network of shareholders requires significant effort by researchers, so consistent funding is critical. Additionally, because researchers are not directly observing the dugongs, reports can be difficult to verify.
On this point, Patankar said, “The efficacy of these methods is not influenced by [which stakeholders are] involved but rather by how much rigour they put in while collecting data, and data validity efforts by researchers during the analysis phase.”
“It is generally advisable to photo-document as much as possible since it validates the sightings directly. But that is not always possible in the sea or while flying,” said Sivakumar. “Verifiable evidence in the form of pictures and videos again is stakeholder-specific. Fishers do not rely on smart-gadgets, and thus cannot provide footage. But their knowledge of the sea is immense and reliable. On the other hand, all other important sightings have been photo-verified by SCUBA divers and defence bodies, which are more active in sharing footage.”
Read more: Why India needs its fishers to save the vanishing dugongs and their habitat
Future plans
This study was only a part of a larger, multi-phase recovery programme for dugongs in the Andaman Islands proposed by Sivakumar. The first phase, which has been ongoing for the last seven years, is coming to an end this year. “However, this programme must continue for the next 15 years to get visible outcomes as this species is a slow breeder and it takes time to recover. Further, continuous contact with stakeholders, especially the local communities, is very important. Otherwise, all our efforts in the past will be in vain.”
CITATION:
Gole, S., Prajapati, S., Prabakaran, N., Johnson, J. A., & Sivakumar, K. (2023). Herd Size Dynamics and Observations on the Natural History of Dugongs (Dugong dugon) in the Andaman Islands, India. Aquatic Mammals, 49(1), 53-61.
Dugong. (2016, June 20). Wildlife Institute of India. https://wii.gov.in/campa_Dugong#:~:text=Dugongs%20are%20protected%20in%20India,in%20its%20number%20and%20range.
Banner image: Dugong in Ritchie’s archipelago, Neil Island, Andamans. Photo by Vardhanjp/Wikimedia Commons.