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Only 1 of 52 pilot whales survives mass stranding in Indonesia

One of 52 individual shortfin pilot whales (Globicephala macrorhynchus) that died washed ashore on the beach of Patereman Village, Modung District, Bangkalan Regency, East Java. Photo: BPSPL Denpasar

  • Two of the three whales that initially survived later became stranded again and died.
  • Researchers are trying to determine the cause of the mass stranding, just the latest one in Indonesia.

Just one of the 52 short-finned pilot whales that washed up on an Indonesian shore last week survived, an official said.

Volunteers and local authorities on the island of Madura initially managed to save three whales, pushing them back out to sea.

But the trio became stranded again at a different location, and two of them died, according to Permana Yudiarso, the head of the marine resources agency in neighboring Bali island.

Contact with the rocky ocean floor had injured them somewhat, said I Made Jaya Ratha, a veterinarian who was among those at the scene, though they were still in relatively good condition.

The governor of East Java province, Khofifah Indar Parawansa, said that according to volunteers, “some of the whales got back to the coast again as their mothers are still stranded at the beach.”

The pilot whales in Madura. Image courtesy of the Bali marine resources agency.

Researchers are now trying to figure out why the whales ended up on land, just the latest mass beaching incident in the country with the world’s longest coastline.

Results of the necropsies — autopsies performed on animals — now underway at Airlangga University in the provincial capital Surabaya will take about a month to come in, Permana said.

Observers cited water pollution, extreme weather and shipping activity as among the possible causes of the stranding — though they cautioned they could only speculate.

“The main cause can only be known from the necropsy of the alpha pilot whale apart from the social behavior and condition of the group members,” said Adriani Sunuddin, a researcher in the marine science department at the Bogor Agricultural Institute (IPB).

Pilot whales — which, despite their name, are actually a type of dolphin — are highly social, tending to travel in groups of 30 or more immediate family members.

“To my knowledge, nobody’s figured out yet why they strand the way they do,” marine biologist Amy Van Cise told Mongabay in 2018. “But when they do, you’re losing what seems to be basically an entire social group. If one animal in that group strands, they all strand together.”

Short-finned pilot whales have been recognized as a single species, but a recent study found that two unique subspecies actually exist: the round-headed “Shiho” type, left, and the square-headed “Naisa” type, right. Image by Natalie Renier, Woods Hole Oceanographic Institution.

Indonesia has sought to train its citizens to deal with sea mammal strandings, setting up groups of first responders around the country.

Sekar Mira, a researcher at the Indonesian Institute of Sciences (LIPI), said live whales must be separated from dead ones.

He also cautioned locals from pouring water into their blowholes, which could suffocate them.

The East Java government provided excavators for a burial that began over the weekend. Image courtesy of the Bali marine resources agency.

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