Genetic connectivity and diversity of endangered species the scalloped hammerhead sharkSphyrna lewini(Griffith & Smith 1834) population in Indonesia and Western Indian Ocean

The scalloped hammerhead shark Sphyrna lewini is an endangered species which expected to population declined worldwide including in Indonesia due to overexploited. However, there is a lack of information regarding recent population structure to promote proper management and conservation status in Indonesia. This study aimed to investigate the genetic diversity, population structure and connectivity of S. lewini population in Indonesia from three major sharks landing sites in Aceh (n= 41), Balikpapan (n= 30), Lombok (n= 29), and additional sequences retrieved from West Papua (n= 14) and Western Indian Ocean population (n= 65). Analyses of mitochondrial CO1 gene successfully identified a total of 179 sequences of S. lewini with an average 594 bp nucleotide with 40 polymorphic loci in 4 haplotypes for Indonesian population and 8 haplotypes for Western Indian Ocean. The overall values of genetic diversity in Indonesia was high (Hd= 0.7171; π= 0.0126), with the highest was in Aceh (Hd= 0.6683; π= 0.0198), and the lowest was in Papua (Hd= 0.1429; π= 0.0005), while in Western Indian Ocean the overall value was fairly low (Hd= 0.2322; π= 0.0010). The AMOVA and F ST revealed three significant population subdivisions in Indonesia ( F ST = 0.4415; p < 0.001) with separated population for Aceh and West Papua, and a mixing population between Balikpapan and Lombok ( F ST = 0.044; p = 0.089), whereas relatively no significant differentiation within population in Western Indian Ocean ( F ST = −0.0131; p = 0.6011), and significant different level showed by Indonesian population compared with Western Indian Ocean population ( F ST = 0.7403; p < 0.001). The construction of haplotype network exhibited evidence of gene flow and haplotype sharing between populations. This result indicated a complex and limited connectivity population of S. lewini in Indonesia, and between Western Indian Ocean in regional scale which need co-management action across region.