Population structure of endangered spinetail devil ray (Mobula mobular) in the Lesser Sunda Seascape, Indonesia, revealed using microsatellite and mitochondrial DNA

For decades, bycatch from drift gillnet fisheries has increased in the LSS, posing a greater threat to their populations. Migratory species require population-based management to effectively address their conservation needs and ensure their long-term survival. The population structure of the spinetail devil ray in the LSS was investigated using microsatellite and mitochondrial DNA. Eight microsatellite markers and mitochondrial DNA (mtDNA) NADH-dehydrogenase subunit 5 were analyzed from 36 samples collected from three locations within the LSS: East Flores, West Manggarai, and East Java. The analysis of microsatellite data revealed significant genetic differences between the three locations, with East Flores and East Java showing the most significant differences. The mitochondrial DNA analysis also revealed significant genetic differences between the three locations, with East Flores and East Java showing the most significant differences. The genetic differentiation index (Fst) was used to compare the genetic differences between the locations. The results showed that East Flores and West Manggarai had a nonsignificant Fst value, indicating that they may belong to the same subpopulation. In contrast, East Flores and East Java, and West Manggarai and East Java had significant Fst values, indicating that they belong to different subpopulations. The results suggest that the spinetail devil ray in the LSS is divided into two distinct subpopulations: the Savu Sea (East Flores and West Manggarai) subpopulation and the East Java subpopulation. The study highlights the importance of population-based management for the conservation of the spinetail devil ray in the LSS. Even though there are two potential subpopulations in the LSS, co-management of this species should be prioritized due to the indication of shared haplotypes between the locations. This suggests that the two subpopulations may be connected and that conservation efforts should focus on protecting the entire population. The study provides valuable information for the development of effective conservation strategies for the spinetail devil ray in the LSS.