Dugong

Context: A new global report released at the IUCN Conservation Congress in Abu Dhabi has warned that India’s dugong (sea cow) populations in the Gulf of Kutch, Gulf of Mannar–Palk Bay, and Andaman & Nicobar Islands.

About Dugong:

What it is?

• Dugong (Dugong dugon) is a large herbivorous marine mammal, closely related to manatees and more distantly to elephants.
• They are slow-moving, gentle sea-grazers that inspired ancient myths of mermaids due to their appearance and behaviour.

Habitat (Indian & Global):

• Found in warm, shallow coastal waters of the Indian and Pacific Oceans.
• Major Indian habitats: Gulf of Mannar–Palk Bay (TN), Andaman & Nicobar Islands, and Gulf of Kutch (Gujarat).
• Globally distributed from East Africa to Australia, with the largest stable population near northwestern Australia.

Conservation Status:

• IUCN Red List: Vulnerable (declining populations since 1982).
• Wild Life (Protection) Act, 1972 (India): Schedule I – highest level of legal protection.

Key Features of Dugongs:

• Grow up to 3 m long and weigh 300–420 kg: Dugongs are large, streamlined marine mammals whose considerable size supports slow movement and constant grazing in shallow coastal waters.
• Have a whale-like tail fluke and paddle-shaped flippers: Their tail fluke enables gentle, rhythmic swimming, while broad flippers help in manoeuvring through seagrass meadows where they forage.
• Exclusively herbivorous, feeding mainly on seagrass meadows: Dugongs rely entirely on seagrass for nutrition, making them one of the few strictly plant-eating marine mammals and tightly linking them to coastal ecosystems.
• Consume 30–40 kg of seagrass daily, acting as “ecosystem engineers”: Their heavy grazing naturally trims seagrass beds, preventing overgrowth and encouraging healthy regrowth, which sustains diverse marine life.
• Seagrass habitats maintained by dugongs are excellent blue carbon sinks: By promoting seagrass productivity and turnover, dugongs indirectly support the storage of large amounts of carbon in sediments, aiding climate regulation.
• Long lifespan (up to 70 years) but very low reproductive rate: Female dugongs give birth only once every 3–7 years, making population recovery slow and increasing vulnerability to environmental and human pressures.

Major Threats to Dugongs:

• Habitat Loss & Seagrass Degradation: Coastal pollution, sedimentation, turbidity, dredging, and port development destroy seagrass meadows—the dugong’s only food.
• Fisheries Bycatch: Accidental entanglement in fishing nets is the biggest killer across Tamil Nadu, A&N Islands, and Gujarat.
• Marine Pollution & Heavy Metals: A recent study detected arsenic, cadmium, chromium, mercury & lead in dugong tissues, entering through wastewater discharge and agricultural runoff.