First Evidence of Neonatal Whale Sharks (Rhincodon typus) in Saleh Bay, West Nusa Tenggara, Indonesia

The reproductive biology of the whale shark (Rhincodon typus), the world’s largest fish, remains poorly understood, in large part due to the rarity of observations of neonates and of breeding behaviours. Although several regions in Indonesia, including Saleh Bay (West Nusa Tenggara Province), have been identified as aggregation and sighting sites for juvenile whale sharks (2–7 m total length, TL), smaller individuals from these potential nursery areas have not been previously documented. In August 2024, fishermen operating lift-net fishing vessels (bagans) in eastern Saleh Bay reported five separate sightings of a small whale shark estimated at 1.2–1.5 m TL and approximately four months old. Subsequently, on 6 September 2024, a male neonate measuring approximately 135–145 cm TL, estimated to be around four months old, was incidentally caught inside a bagan lift-net. These observations represent the first records of neonatal whale sharks in Indonesia and among the smallest free-swimming individuals ever documented globally, and suggest that Saleh Bay may serve as a pupping and early nursery area for whale sharks. These findings highlight the ecological significance of Saleh Bay for the early life stages of whale sharks and underscore the importance of collaborative monitoring and citizen science involving bagan fishermen in advancing the research and conservation of this endangered species.