Baby whale shark offers rare clue to where ocean’s giants are born

A rare newborn whale shark discovered in Indonesia’s Saleh Bay could provide scientists with one of their strongest clues yet about where the world’s largest fish give birth.

The 1.5-metre-long juvenile was filmed by local fishermen in Saleh Bay, on the Indonesian island of Sumbawa, in September 2024. Scientists estimate it was only about four months old, making it the first neonatal whale shark documented in Indonesia and one of only a few dozen ever recorded worldwide, BBC writes. 

Whale sharks can grow to around 12 metres and weigh as much as six elephants. Yet despite their size and their presence in tropical and warm waters around the world, scientists have never directly observed a whale shark mating or giving birth.

Marine scientist Mochamad Iqbal Herwata Putra of Konservasi Indonesia said the discovery offered a "rare glimpse" into an early stage of the species’ life that scientists almost never see.

Saleh Bay may provide ideal conditions for young whale sharks. The enclosed cove is fed by nutrient-rich water from the deep ocean and is surrounded by mangroves that support abundant krill and other food.

Local fishermen operate floating fishing platforms known as bagans, using lights at night to attract fish into nets. It was from one of these platforms that fishermen alerted scientists after spotting the young whale shark shortly after 4:30 a.m.

Herwata Putra suspects the sheltered bay could serve as a birthing ground or nursery, although scientists cannot yet determine whether the shark was born there or arrived shortly afterward.

Ben D'Antonio, a research scientist at the Shark Research Foundation, said the discovery could be significant in identifying habitats essential to the species’ survival.

Finding a nursery ground is "a fundamental discovery", D'Antonio said, noting the importance of cooperation between scientists and local fishing communities.

Whale shark populations have declined by more than half since the 1980s, and the species is classified as endangered. The fish face threats from fishing, shipping and climate change, while their important habitats remain poorly understood.

Scientists’ knowledge of whale shark reproduction has largely come from a 10-metre female found in Taiwan in 1995. Nicknamed "Megamamma", the shark contained 304 fertilised eggs and embryos, showing that whale sharks hatch eggs internally and give birth to live young.

Only 33 neonatal whale sharks have been documented by scientists, with sightings spread across tropical regions from the Atlantic Ocean to the Arabian Sea and the Galapagos.

Researcher Freya Womersley has identified another possible clue. Many of the recorded newborns were found near permanent oxygen minimum zones — areas of the ocean with very low oxygen levels that are avoided by many predators. Such areas may provide young whale sharks with protection while also concentrating plankton, giving them a rich food source.

Womersley believes further research could eventually reveal the species’ elusive breeding grounds. "I think it's only a matter of time before someone finds the right shark, puts the right device on it, the stars align, and we get that incredible footage," she says. "I say 'a matter of time' – how long that is, I do not know."

In Saleh Bay, attitudes toward whale sharks are also changing. Once viewed by some fishermen as competitors, the animals have become a major attraction for ecotourism.

Konservasi Indonesia is seeking to establish a marine protected area in the northern part of the bay specifically for whale sharks.

"This area is like home for the whale sharks," says Herwata Putra. "If we can protect this critical habitat, we can help the recovery of the regional population.”

By Sabina Mammasli