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Picture Courtesy: The Guardian

Context:

The Expert Appraisal Committee (EAC) of the Union Ministry of Environment, Forest and Climate Change has asked the Tamil Nadu government to substantially revise the design of the proposed International Dugong Conservation Centre at Manora in Thanjavur district, citing concerns over extensive concrete construction in ecologically sensitive coastal areas.

Dugong:

The dugong (Dugong dugon) is a large marine mammal often called a “sea cow” because of its gentle grazing habits. It belongs to the same biological group as manatees, but unlike them, dugongs live exclusively in marine (saltwater) environments.

Distribution in India

Dugongs prefer shallow, warm coastal waters where seagrass meadows are abundant. In India, their presence is mainly recorded in:

• Andaman and Nicobar Islands
• Gulf of Mannar
• Palk Bay
• Gulf of Kutch

These regions provide suitable feeding grounds and relatively calm waters essential for their survival.

Ecological role: Dugongs are strict herbivores, feeding primarily on seagrass varieties such as Cymodocea, Halophila, Thalassia, and Halodule.
While grazing, they disturb the sea floor, which helps recycle nutrients and encourages new seagrass growth. Because of this ecological function, they are often referred to as “farmers of the sea.”

Lifespan: Dugongs are long-lived animals, with a lifespan that can extend to around seven decades. They are generally solitary, though they may sometimes be seen in small groups or as mother–calf pairs, especially during early life stages.

Reproductive Characteristics

Dugongs have a slow reproductive cycle, which makes population recovery difficult:

• Females reach sexual maturity at approximately 9–10 years of age
• A single calf is born after a long gestation period
• The interval between births ranges from 3 to 5 years

This low reproductive rate leads to very gradual population growth.

Population status:

The dugong population in Indian waters has declined sharply and is now estimated to be around 200 individuals. Habitat degradation, accidental entanglement in fishing gear, boat strikes, and loss of seagrass beds have reduced both their numbers and geographic range.

Conservation status:

• Listed as Vulnerable on the IUCN Red List at the global level
• Categorized as Regionally Endangered within Indian waters

Dugongs receive the highest level of legal protection under Schedule I of the Wild Life (Protection) Act, 1972, which prohibits hunting and trade.

Dugong conservation reserve:

In 2022, India notified its first Dugong Conservation Reserve in Palk Bay, Tamil Nadu. The protected area spans 448.3 square kilometres and focuses on safeguarding critical seagrass habitats and reducing human-induced threats.

Agreements:

India supports global dugong conservation through:

• Membership in the Convention on Migratory Species (CMS) since 1983
• Participation in the Dugong Conservation Memorandum of Understanding (MoU) signed in 2008

Challenges in Dugong Conservation:

• Degradation of seagrass ecosystems: Dugongs depend entirely on the seagrass meadows for their food, yet these important habitats are declining at an alarming rate worldwide. A major global assessment by Waycott et al. (2009) synthesised data from 215 studies and found that the rate of seagrass loss accelerated from about 9% per year before 1940 to around 7% per year after 1990, making seagrasses one of the most threatened coastal ecosystems on Earth.

• Impacts of Climate Change: Climate change affects the health of the seagrass ecosystems that underpin dugong survival. Research on climate interactions with coastal habitats shows that rising sea temperatures, increased ocean acidity, and more frequent extreme weather events can damage seagrass meadows, reduce dugongs’ food supply and forcing them to move to less suitable areas.

• Effects of pollution and marine debris: Nutrient pollution, sedimentation from rivers, industrial discharge, and widespread plastic waste all reduce coastal water quality, limiting light penetration necessary for seagrass growth. A report by the United Nations Environment Programme (UNEP) indicates that poor water quality is a key driver of seagrass decline globally, which directly impacts dugong foraging success.

• Small and isolated populations: In countries like India, dugong populations are small and highly fragmented. With an estimated 200 individuals distributed across the Gulf of Mannar, Palk Bay, Gulf of Kutch, and the Andaman & Nicobar Islands, these tiny populations are more vulnerable to local extinctions, genetic decline, and environmental disasters, making conservation even more challenging.

Conclusion:

Dugong conservation remains a challenge because the species depends on fragile seagrass habitats, reproduces slowly, and lives in coastal areas heavily used by humans. Habitat loss, fishing-related deaths, pollution, and climate change together make population recovery difficult, highlighting the need for strong habitat protection and community-based conservation.

Source: The Guardian