Post-Release Survival and Behavioral Recovery of a Rehabilitated Short-Finned Pilot Whale (Globicephala macrorhynchus) in the South China Sea Revealed Through Satellite Tracking.

Post-release monitoring is critical for evaluating the success of rehabilitating stranded cetaceans, yet such data are scarce for many species in the South China Sea (SCS). We satellite-tracked a rehabilitated subadult male short-finned pilot whale (Globicephala macrorhynchus; named "Haitang"), following a live stranding on Hainan Island, China. We collected tracking locations and behavioral data over a 52-day period and conducted a dedicated 3-day expedition to resight Haitang at sea in the sixth week post-release. Results confirm Haitang's survival beyond the critical 6-week benchmark. Its daily movement distance (6.2-145.9 km) and speed (0.6-5.9 km/h) were consistent with those of healthy, free-ranging conspecifics. Furthermore, diving behavior including time-at-depth budgets, maximum dive depth (621 m), diel patterns, and thermal-depth profiles reflected natural foraging activity and environmental adaptation. Notably, high density and spatial proximity of local conspecifics during the post-release expedition indicate favorable conditions for social integration and long-term survival. Movement trajectories suggest that the Qiongdongnan slope represents a critical habitat for this species in the northern SCS. This study provides the first empirical evidence of successful rehabilitation and release of short-finned pilot whale in the SCS, supporting future stranding response and conservation initiatives.