## 4 Discussion
### Limitations to Study  
This study had several limitations that should be acknowledged. First, the number of tags deployed in each region was limited and varied across the regions, leading to potential sampling biases. For example, while 1375 individuals have been identified in Raja Ampat [6], only 14 individuals were satellite-tagged. Similarly, only five, eight, and six tags were deployed in Berau, Nusa Penida, and Komodo, respectively, despite larger population sizes of 155, 624, and 1085 individuals in these regions [7; 8; 25]. This disparity suggests that the movement patterns shown by the tagged manta rays might not fully represent the overall movement dynamics in each region. Further, the reef manta rays in Raja Ampat form a metapopulation consisting of at least three different local (sub)populations occupying different habitats [12], and the number of tags deployed in each of these local (sub)populations was varied, largely due to the financial and logistical challenges of obtaining and deploying the satellite tags. This variability may hinder our ability to compare the movement patterns of the reef manta rays within each region and across all the regions. The relatively short tracking durations constrain the understanding of movement patterns by omitting long-term behaviors, rare events (e.g., long-distance migration and responses to unusual environmental conditions), and environmental influences while also introducing potential biases in behavioral interpretation. The recursive analysis employed in this study identified several key areas and sites frequently visited by the satellite-tracked reef manta rays, as indicated by the high cumulative number of revisitations (Figure 3). However, the visitation times calculated through the recursive analysis may not fully reflect the actual residency patterns and visitation durations of the reef manta rays and should, therefore, be interpreted with caution. The recursive analysis was based on the trajectories of the GPS-tracked animals, as outlined in [PERSON] et al. [39]. In the current study, GPS position data were only transmitted when the satellite-tracked reef manta rays surfaced, limiting our ability to accurately determine their complete visitation time at specific sites. It is possible that the reef manta rays moved away significant distances from these locations while remaining submerged, returning to the surface after an extended period of time, at which point their locations were recorded again. As a result, the true extent of their visitation times at each site may be overestimated due to the gaps in tracking during periods of submersion. The limitations in accurately determining visitation times through the recursive analysis are closely tied to the variability in the Fastloc GPS data collected, which is influenced by several factors related to the tags' performance and the behavior of the manta rays. The difference in the number of Fastloc GPS data between the tags could be attributed to several factors, including variations in the frequency of Fastloc GPS data collection as set during programming, the tracking period, and environmental conditions that affect the ability of the tag's antenna to breach the sea surface, as well as the surfacing behaviors of the manta rays. Additionally, some tags may have experienced technical issues, such as malfunctioning sensors or limited connectivity. It is also possible that individual manta rays exhibited different movement patterns, which could have influenced the frequency of data transmission. Finally, the spatial configuration of the islands in the study regions may result in an underestimation of the actual distances traveled by the satellite-tagged reef manta rays, as the distance calculations used did not account for the necessity of navigating around landmasses. In reality, the reef manta rays may follow more circuitous routes to reach their destinations, leading to longer travel distances than those calculated.