The genetic connectivity of the silky shark (Carcharhinus falciformis) across Indonesia

Abstract

<p>Silky shark (<em><a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/carcharhinus" title="Learn more about Carcharhinus from ScienceDirect's AI-generated Topic Pages">Carcharhinus</a></em><em> falciformis</em>) has been listed as CITES Appendix II and Vulnerable by IUCN red list. Reports from Indian, Pacific and Atlantic Ocean showed a sharply declining <em>C. falciformis</em> population every year, including in Indonesia. Despite this issue, information on local and regional <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/population-genetics" title="Learn more about genetic population from ScienceDirect's AI-generated Topic Pages">genetic population</a> structure of this species is still lacking. In this research, we aim to assess the population condition of <em>C. falciformis</em> across Indonesia Fisheries Management Area (FMAs), using mitochondrial genetic data. A total of 225 fins or tissue samples collected from various traditional fish market and shark-fin exporters across Indonesia, then sequenced using mtDNA control region, yielding 510 bp of sequence. The overall Haplotype diversity is high (h: 0.534 ± 0.035). Meanwhile, the <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/nucleotide-diversity" title="Learn more about nucleotide diversity from ScienceDirect's AI-generated Topic Pages">nucleotide diversity</a> (θπ) is low (range of 0.00067 – 0.00201) compared to the Atlantic and Red Sea. In addition, the <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/genetic-divergence" title="Learn more about genetic diversity from ScienceDirect's AI-generated Topic Pages">genetic diversity</a> of <em>C. falciformis</em> in Indonesia is lower than other pelagic shark species. Furthermore, AMOVA and Fst results showed a significant structure between Aceh and other locations in Indonesia. Samples from across Indonesia also showed a certain degree of haplotype sharing but with significant genetic structure with others, additionally, the combined dataset revealed a pattern that is similar to previous studies, which showed that the Atlantic population is different from the rest. The distinct genetic population of <em>C. falciformis</em> observed in Aceh may indicate that this population should be managed separately. Meanwhile, the shared genetic information within the Timor Sea indicates the necessity of establishing a co-management plan between Indonesia and neighbouring countries such as Timor-Leste and Australia to ensure the sustainable use of this marine resource.​​​​​​​</p>