Mass pilot whale stranding in Indonesia raises questions about ocean health

Villagers in central Indonesia rescued 34 short-finned pilot whales following a mass stranding on March 9, but despite their overnight efforts were unable to save 21 others.

Mongabay Indonesia’s Ebed De Rosary reports that residents first discovered the pod in the shallow waters off Deranitan village, in East Nusa Tenggara province, at approximately 3:30 p.m. local time. Local police coordinated with the local naval garrison and representatives from the fisheries ministry to launch a joint rescue operation.

Working past midnight, teams of officials, security personnel and residents using boats managed to guide 34 of the whales back out into deeper waters. Of the 21 whales that perished, authorities identified The largest was a male measuring 5.1 meters (16.7 feet). The species, Globicephala macrorhynchus, is not considered threatened on the IUCN Red List.

Imam Fauzi, head of the marine conservation area agency in Kupang, the provincial capital, said necropsies were conducted immediately to determine the cause of death. While the fisheries ministry is investigating the incident, local environmental NGOs like Walhi NTT are urging the government to expand the scope into a “thorough scientific investigation” to identify the root ecological triggers.

Christofel Oktavianus Nobel Pale, head of the aquatic resources management program at Nusa Nipa University, said the region’s unique topography, characterized by shallow waters, narrow bays and steep gradients, can disrupt the sensitive echolocation systems pilot whales use to navigate.

“Pilot whales have high social cohesion; when one individual, perhaps sick or disoriented, enters shallow water, the rest follow even into danger,” Pale told Mongabay Indonesia.

Yuvensius Stefanus Nonga, executive director of Walhi NTT, said the stranding is a “signal that must not be ignored,” suggesting it may indicate broader ecological disruption linked to climate change, shifting prey distributions, or human-caused ocean noise.

Indonesia’s waters serve as a critical migratory route for dozens of whale and dolphin species, yet, as Mongabay previously reported, the country’s Ocean Health Index, a framework that measures the health and sustainability of regional oceans, remains relatively low at 65 out of 100.

Experts emphasize that understanding the root causes of these frequent whale strandings is essential for improving national marine conservation policies.

Banner image: Short-finned pilot whale (Globicephala macrorhynchus). Image by ©bev435. CC BY-NC 4.0.