Saleh Bay Emerges as Prime Candidate for World's First Verified Whale Shark Nursery

Marine scientists have confirmed the presence of a neonatal whale shark in Saleh Bay, located in West Nusa Tenggara, Indonesia, a development that positions the bay as a leading candidate for the world's first scientifically verified pupping ground for the species, Rhincodon typus. This significant observation, detailed in the journal Diversity, addresses a long-standing gap in marine biology concerning the reproductive cycle of the planet's largest fish. The documented individual was an incidentally caught male neonate, measuring between 135 and 145 centimeters in total length, with an estimated age of approximately four months based on established growth curves.

This finding is notable because documented sightings of free-swimming whale sharks under 1.5 meters are exceptionally rare globally, with only 33 such records existing over more than a century of research. Prior to this confirmation, local fishermen operating traditional lift-net vessels, known as bagans, in eastern Saleh Bay reported five separate sightings of small whale sharks, estimated between 1.2 and 1.5 meters in length, during August 2024. The subsequent capture and release of the four-month-old male on September 6, 2024, provided the crucial data point supporting this hypothesis.

Mochamad Iqbal Herwata Putra, Focal Species Conservation Senior Manager at Conservation International Indonesia (KI), stated that this evidence signals strongly that Saleh Bay functions ecologically as a nursery area for these massive fish. The bay's ecological profile appears uniquely suited for the early life stages of whale sharks, offering relatively calm waters shielded from the open ocean turbulence. This environment is coupled with high nutrient productivity from local mangrove, seagrass, and coral reef ecosystems, creating a stable feeding ground rich in the plankton and small fish necessary for neonatal growth.

Despite its ecological promise, the bay's vulnerable neonates face tangible threats, including entanglement in fishing gear, potential water quality declines from proximate coastal activities, and increased vessel traffic. This scientific breakthrough is now galvanizing conservation initiatives, with KI and its collaborators actively engaging government authorities to formalize protection by establishing Indonesia's inaugural whale shark-focused Marine Protected Area (MPA) within Saleh Bay. The role of local bagan fishermen has been indispensable, providing on-the-ground observations that advance critical marine research for this IUCN-listed endangered species.

Saleh Bay, which spans 1,459 square kilometers, is already recognized as a significant habitat, hosting the second-largest population of whale sharks in Indonesia after Cendrawasih Bay. To support conservation goals and promote sustainable eco-tourism, a Whale Shark Learning Center was inaugurated on February 3, 2025, in Labuan Jambu Village, Sumbawa Besar. This center, a collaboration between Konservasi Indonesia, the West Nusa Tenggara Provincial Government, and the French Embassy in Indonesia, aims to educate the community and visitors on whale shark ecology and responsible interaction protocols. Researchers, however, maintain that further long-term monitoring is requisite before Saleh Bay can be officially confirmed as a definitive birthing site.