Abstract. Al Malik MD, Pertiwi NPD, Sembiring A, Yusmalinda NLA, Ningsing EY, Astarini IA. 2020. Short Communication: Genetic structure of Longtail Tuna Thunnus tonggol (Bleeker, 1851) in Java Sea, Indonesia. Biodiversitas 21: 3637-3643. Thunnus tonggol (Longtail Tuna) is an economically important fish found in Indonesia waters, however, the information regarding this fish is lacking. Known to be a neritic fish and found in shallow water, Java Sea is one of the ideal habitats for T. tonggol species. Due to high fishing rates activities in Java Sea, a better management plan to ensure the conservation and fisheries sustainability around this area is needed, especially to protect T. tonggol population. In order to complete the Indonesian tuna data, we aim to study the diversity and genetic structure of T. tonggol in Java Sea at three different locations; i.e. Semarang, Banjarmasin, and Jakarta. In this study, population genetic methods with the marker of mitochondrial DNA (mtDNA) control region were used in population structure analysis. A total of 115 specimens were collected from the fish market around the area of study locations and amplified using polymerase chain reaction (PCR) and sequenced using Sanger methods. The result showed genetic diversity (Hd) value of 0.99366, and nucleotide diversity (π) value of 0.01906. Both of these values indicated high genetic diversity. Population analyses using Analysis of Molecular Variance (AMOVA) showed nonsignificant differences between the three populations of study (mixing population), with the ΦST value of 0,00375 (p-value > 0.05). Based on this result, the fisheries management for T. tonggol in Java Sea needs to be managed as one single population management.

Abstract. Astarini IA, Ningsih EY, Simanungkalit D, Ardiana SA, Al Malik MD, Yusmalinda NLA, Sembiring A, Pertiwi NPD, Cahyani NKD, Collins A. 2021. Genetic variation of longtail tuna Thunnus tonggol landed in four fish markets in Indonesia based on mitochondrial DNA. Biodiversitas 22: 1644-1651. Longtail tuna (Thunnus tonggol, Family: Scombridae) is an economically valuable neritic species found in tropical and subtropical waters in the Indo-Pacific region. High catch numbers, which have been decreasing, could negatively impact this tuna’s population level. Little research has been conducted on the longtail tuna population in Indonesia. This study aims to determine the genetic diversity and potential population structure of longtail tuna landed in four fish markets in Indonesia (representing three sampling locations because two markets are relatively close to each other) based on sequences of a region of mitochondrial control region (d-loop). A total of 101 samples, out of 110, were identified and confirmed as T. tonggol species by amplifying and sequencing a fragment of d-loop (amplicons ranging from 482 - 523 bp). Neighbor-joining analysis resulted in a topology with all samples grouped into one clade with an average genetic distance of 0.020. Meanwhile, haplotype diversity (Hd) and nucleotide diversity (?) values of the longtail tuna samples were 0.9939 and 0.0192, respectively. The fixation index (Fst) value was -0.00507, with p> 0.05, which indicates that there is no significant population structure among the longtail tuna collected from four fish markets representing three sampling locations. The results of this analysis can be used as basic data in planning sustainable fisheries management efforts.

Abstract. Tapilatu ME, Wijayanti DP, Subagiyo, Sembiring A, Yusmalinda NLA, NIngsih EY, Malik MDA, Pertiwi NPD. 2023. Genetic diversity of wedgefishes and guitarfishes at landing sites in east Indonesia using Cytochrome Subunit I (COI). Biodiversitas 24: 3120-3127. Wedgefish and guitarfish are considered endangered and protected by law in Indonesia due to pressure from overexploitation. They are highly exploited because of their economic value. This condition impacts the decline in the number of populations to the value of genetic diversity. This study used mitochondrial DNA to assess the genetic diversity of wedgefishes and guitarfishes which landed in the eastern part of Indonesia. We found Rhynchobatus australiae (Whitley, 1939) to be the most common species (14 out of 26 sequenced samples), with Glaucostegus typus (Bennett, 1830) and Rhinobatos jimbaranensis (Last, White, & Fahmi, 2006) appearing infrequently. COI sequences were obtained from the NCBI database and utilized in the study to compare population differentiation. Among the R. australiae populations, the results showed that the genetic diversity (Hd) values from Papua, Bali, and Lombok were 1.00, 0.67, and 0.75, respectively. In Papua, G.typus populations showed genetic diversity values of 0.90. R. jimbaranensis from Bali showed a genetic diversity of 0.50. Papua populations indicated higher genetic diversity than Bali and Lombok populations. Furthermore, the analyses of pairwise FST values and AMOVA indicated moderate genetic divergence across reference populations of R. australiae and G. typus in this study. Based on this value, a cautious conservation strategy in optimizing fisheries management will be required to limit anthropogenic impacts.

Longtail tuna (Thunnus tonggol) is one of the oceanodromus neritic species and the migration pattern follows the water currents. Currently, this species has not been widely studied in Indonesian waters, so it is nesessary to study the identification of morphology and genetic diversity. The molecular approach employed in this study is DNA barcoding using mitochondrial D – loop locus. This study can explain the importance of species genetic information in stability and resilience. This study aims to determine the identification of morphology, phylogenetic and genetic diversity of longtail tuna at two locations in PPI Kedonganan, Bali dan PPP Muncar, Banyuwangi. The molecular analysis was done in several stages, i.e DNA extraction, Polymerase Chain Reaction, electrophoresis and sequencing. Based on the result of sequencing and analysis, 33 samples of longtail tuna was found. The result of phylogenetic tree reconstruction from two locations showed one clade with genetic distance value among longtail tuna species ranging from 0.000 – 0.042 for all close kinship samples. The haplotype diversity (Hd) value of longtail tuna was 0.9905 and nucleotide diversity (?) was 0.020. The high value of genetic diversity indicated that two longtail tuna populations have a high survival ability to adapt on environmental changes. Index fixation analysis (Fst) has a value of 0.0299, p - value > 0.05. The index fixation value indicated no significant population difference. The result of this study can be use as basic data in planning genetic conservation strategies with sustainable fisheries management efforts. Keywords: Tuna; Thunnus tonggol; Genetic Marker

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