## 4 Discussion
### Implications for Conservation and Management  
This study shows that satellite-tracked reef manta rays from four regions in central and eastern Indonesia (Berau, Nusa Penida, Komodo, and Raja Ampat) demonstrated restricted movements and high residency patterns within tagging regions, especially within and around the marine protected areas (MPAs) which have been set up in these regions (Figure 4). These patterns suggest that the existing MPAs should provide a significant level of protection for reef manta rays, given that many of the known cleaning stations and feeding sites for reef manta rays are located within these protected areas, particularly in Nusa Penida [8], Komodo [7], and Raja Ampat [6]. Though [PERSON] and [PERSON] [58] showed some exchanges of individuals between Nusa Penida and Komodo through photographic identification, our study using satellite telemetry found no evidence of such exchanges, suggesting they may not be particularly common. Our study involved relatively small sample sizes and limited tracking durations in these regions. While the lack of exchange observed is notable based on the available telemetry data, tracking a larger number of rays over extended periods would be necessary to better understand the frequency of movement between these regions. The limited long-distance movements and the high residency of reef manta rays demonstrated in our study underscore the necessity of managing reef manta ray populations in these four regions as distinct management units. Notably, a recent study employing passive acoustic telemetry and network analysis identified three separate subpopulations inhabiting different areas of Raja Ampat, which led those authors to strongly recommend the development of tailored management strategies for each local subpopulation [12]. The satellite-tagged reef manta rays in our study spent considerable time within MPAs across all the tagging regions. Despite the full protection of reef manta rays in Indonesian waters [4], these animals remain vulnerable to anthropogenic threats, particularly from net fisheries operating outside and in the vicinity of MPA boundaries. For instance, oceanic manta rays in East Flores (Figure 1) have frequently been caught incidentally in net fisheries [61]. Given the island formations in the Lesser Sunda and several long-distance movements observed in the photo-identified reef manta rays from both Nusa Penida and Komodo [58], these manta rays are potentially at risk from net fisheries, similar to reports from other regions in the Indo-Pacific. Alarmingly, between 2011 and 2020, oceanic manta rays and other mobulids in Sri Lanka faced massive bycatch, leading to significant declines in catch rates [62]. Similarly, in Mozambique, both the population of manta rays and the number of sightings have continuously declined due to increased mortality from fisheries [63; 64]. Our satellite-tagged reef manta rays, moreover, frequently ventured into areas outside of MPAs, as indicated by their extended home ranges. To mitigate threats to manta rays, particularly in the Lesser Sunda region, the provincial government of Bali (home to Nusa Penida) and the provincial governments of Nusa Tenggara Barat and Nusa Tenggara Timur could adopt strategies similar to those implemented in Raja Ampat, including the implementation of shark and ray sanctuaries and specifically restricting the use of fishing gears known to negatively impact manta rays [5; 24]. Although the Manggarai Barat government has declared a manta ray sanctuary to protect their population in Komodo [65], additional measures are needed to reduce potential threats across the Lesser Sunda. One effective strategy could involve implementing a ban on net fishing within MPAs, as successfully enacted in Raja Ampat [5]. While the Lesser Sundas are protected by a network of relatively small MPAs, net fisheries could be banned within 12 nautical miles from the coast to account for the mobility of reef manta rays in coastal areas and shallow waters throughout the Lesser Sunda Islands [58].