Leopard sharks Stegostoma tigrinum in southern Mozambique: population structure, spatial ecology, and first observations of courtship behaviour

Global shark populations have declined substantially due to overfishing and habitat degradation, yet ecological data remain scarce for many coastal species. The Indo-Pacific leopard shark Stegostoma tigrinum is threatened across much of its range, with the Western Indian Ocean-Southeast Asian subpopulation listed as Critically Endangered. This study presents a 14 yr (2011-2025) data set of underwater surveys and photo-identification records from Mozambique to characterise population structure and ecological patterns along the Inhambane coastline. A total of 9219 surveys recorded 631 S. tigrinum sightings, identifying 164 unique individuals. The population was strongly female-biased (~70%) and dominated by adult and subadult size classes (mean ± SD total length: 1.64 ± 0.30 m). Sighting rates were concentrated at a small cluster of reefs north of Tofo, with 35% of individuals resighted at least once and 27% recorded across multiple years. Sightings were strongly seasonal, peaking during austral summer and co-varying with seasonal patterns in bottom temperature and underwater visibility. An open-population Jolly-Seber (POPAN) model for the reefs north of Tofo estimated a superpopulation of ~88 individuals (95% CI: 50-154), with high apparent survival (Φ = 0.85) and low detection probability ( p = 0.17). Avoidance responses to divers occurred in 55% of sightings and increased significantly when the closest diver was within 5 m. Courtship interactions were documented 3 times, providing the first records of this behaviour for S. tigrinum in the Western Indian Ocean. Overall, this long-term data set provides a foundation for conservation planning and targeted management of S. tigrinum along the Inhambane coastline.