Navua River Delta is an important reproductive area for one shark species.

Neonate and young-of-the-year (YOY) Bull Sharks are regularly captured in this area (Cardeñosa et al. 2016). Fishing surveys between 2014 and 2017 in the Navua River Delta captured 40 Bull Sharks, including three re-captures (Glaus et al. 2019). Most captures were neonates determined by the presence of an open (n = 20) or semi-healed (n = 7) umbilical scar. Animals were primarily captured in the austral summer, which aligns with the Bull Shark parturition season in Fiji (Glaus et al. 2019). Bull Sharks measured between 60–91 cm total length (TL) (Glaus et al. 2019). The size-at-birth for the species ranges between 56–81 cm TL (Ebert et al. 2021). Two YOY individuals with healed umbilical scars measuring 100 and 107 cm TL were captured in late June and early November 2016, respectively. In the Deuba River, a tributary of the Navua River, five neonate Bull Sharks were captured in the same fishing surveys (Glaus et al. 2019). Fisher reports and Traditional Ecological Knowledge show that Bull Sharks are captured up to 8 km upstream of the Navua River mouth. Descriptions of sharks caught in the river (rounded snout, grey-brown in colour, white underbelly) morphologically matched neonate or YOY Bull Shark whose presence in the river is ecologically sound (Cardeñosa et al. 2016). Additionally, this area is used by pregnant Bull Sharks. Two of the 15 pregnant Bull Sharks that were detected on passive acoustic receivers in four rivers on Viti Levu were tracked into the Navua River during three parturition seasons in 2016, 2017, and 2018 (Brunnschweiler et al. unpubl. data 2024). Collectively, these findings underscore the importance of the Navua River as a critical habitat for the Bull Shark’s reproductive cycle.