The Hidden Depths of Marine Mammals in Southeast Asia
SINGAPORE – Contrary to popular belief, Southeast Asia is home to a diverse array of marine mammals, not just in distant waters like Australia, the United States, or Japan. Singapore, for instance, is home to elusive creatures such as the dugong and the Indo-Pacific humpback dolphin. These creatures, along with others, play a crucial role in maintaining the health of our oceans.
Discovering Marine Mammals in Singapore
Mr. Marcus Chua, a mammal expert at the NUS Lee Kong Chian Natural History Museum, highlights the significance of these gentle giants. Their presence indicates that local habitats can support large predators and herbivores alike.
Dr. Louisa Ponnampalam, co-founder of Malaysian marine mammal research and conservation group MareCet, shares her concerns. Losing marine mammals is a red flag, indicating unhealthy water environments, which have direct implications for human well-being.
To mark International Marine Mammal Protection Day on February 19, experts discussed South-east Asia’s marine mammals, their threats, and future research opportunities. Let’s delve deeper into these majestic creatures.
Where to Spot Marine Mammals in Southeast Asia
South-east Asia, a biodiversity hotspot with over 3,000 fish species and 600 types of corals, is home to various marine mammals. In September 2024, a humpback whale was spotted off Pulau Redang, Malaysia, marking its first sighting on the east coast. January 2025 saw another humpback whale sighting off the Philippines.
Several factors determine the suitability of habitats for different marine mammals:
- Depth
- Temperature
- Distance from shore
- Proximity to estuaries
- Presence of ecosystems like mangroves or seagrass
- Water clarity
- Level of human disturbances
Meet the Marine Mammals of Southeast Asia
Humpback whales, once near extinction due to hunting, have made a recovery due to conservation efforts. They are known for their distinctive tail flukes and elaborate mating calls, which can last up to 30 minutes.
Sperm whales, categorized as vulnerable to extinction, are known for their large brain and distinctive block-shaped heads. They are commonly spotted off Southeast Asian coasts between April and July due to their migratory patterns.
Bryde’s whales, nicknamed the “tropical whale,” prefer warmer waters and are known for their lunge feeding and bubble net foraging techniques, which help them herd fish into smaller groups for easier eating.
False killer whales, often mistaken for shark by the untrained eye, are known for their aggressive hunting habits, dining on squid, tuna, and even other dolphins. They can be found off Thailand between December and February.
Irrawaddy dolphins, found in estuaries and coastal waters from Vietnam to Myanmar, are known for their unique appearance and hunting technique, which involves squirting streams of water to herd fish.
Indo-Pacific humpback dolphins, found in estuaries and coastal areas, are known for their pink hue in the Asian region. They play a vital role in the marine ecosystem by maintaining fish populations.
The Indo-Pacific finless porpoise, lacking a dorsal fin, is found in estuaries and shallow waters around Singapore and Malaysia. They spend much of their time near the surface, feeding on small fish and crustaceans.
Dugongs, or “sea cows,” are crucial for seagrass habitats, consuming up to 30kg of seagrass daily. Their presence indicates healthy marine environments.
The Threats to Marine Mammals
Marine mammals face various threats, including marine litter, discarded fishing gear, ship strikes, and commercial fishing practices. Entanglement in ropes and plastic pollution can lead to injury, starvation, and death.
According to the Food and Agriculture Organisation of the United Nations, over 500,000 marine mammals are accidentally captured annually. Ship strikes, common in busy waters like the Malacca Strait, pose a significant risk to these animals.
Dead turtle entangled in fishing nets.PHOTO: ADOBE STOCK
Maritime traffic also contributes to underwater noise pollution, disturbing marine mammals. This issue is not yet legally recognized as a significant threat in South-east Asia.
Coastal development, including land reclamation and dredging, fragments marine habitats, isolating smaller populations and increasing stress on these animals.
Legends from the Deep
Marine mammals are deeply intertwined with local culture and mythology. In Vietnam, whales are worshipped as deities, with elaborate ceremonies held for stranded or dead animals. In Chinese mythology, the Baiji, a freshwater dolphin, is the reincarnation of a maiden who drowned in the Yangtze River.
Indo-Pacific humpback dolphin bones were found in temples dedicated to Mazu, the Taoist sea goddess, used by sailors for protection at sea. Dugong tears were believed to have aphrodisiac properties in Malaysia and Cambodia.
