Population genetic structure of Kawakawa (Euthynnus affinis Cantor, 1849) in Malaysian waters based on COI gene

Abstract

Abstract. Binashikhbubkr K, Setyawan AD, Naim DM. 2023. Population genetic structure of Kawakawa (Euthynnus affinis (Cantor, 1849)) in Malaysian waters based on COI gene. Nusantara Bioscience 15: 258-268. Kawakawa (Euthynnus affinis Cantor, 1849) is widely distributed in the subtropical and tropical waters of the Indo-Pacific region. Still, insufficient data about its stock, management, and protection in Malaysia and nearby waters raises concerns about overfishing and depletion. Therefore, to ensure effective and successful management of a species, it is imperative to conduct a molecular-based assessment of the stock structure. The present study investigated the population genetic structure of E. affinis in Malaysian waters using the mtDNA COI gene. Furthermore, the 632 bp segment of the COI region was sequenced in 372 individuals from 19 distinct populations in Malaysian waters. The results revealed that the genetic divergence varied from low to high. The average Haplotype diversity (Hd) and nucleotide diversity (?) were calculated to be 0.5401 and 0.0045, respectively. Examining haplotype distribution unveiled the presence of 22 unique haplotypes within the COI gene of E. affinis. The analysis of the Neighbor Joining (NJ) tree and the Minimum Spanning Network (MSN) revealed the formation of three distinct clades among E. affinis samples. Analysis of Molecular Variance (AMOVA) showed a significant genetic structure among the 19 populations of E. affinis [(FST = 0.5354 (P < 0.05)]. The neutrality test and mismatch distribution analysis indicated that the specimens underwent a period of population expansion. This study is a significant milestone, providing the first comprehensive documentation of the genetic structure of E. affinis in Malaysia.

Morphometric variations of Kawakawa (Euthynnus affinis Cantor, 1849) in Malaysian and Yemeni waters

“…Previous research on E. affinis has mostly focused on various factors, including reproductive behavior, biological characteristics, stock assessment, genetic structure, and population dynamics (Santos et al 2010;Rohit et al 2012;Johnson and Tamatamah 2013;Sulistyaningsih et al 2014;Nissar et al 2015;Kumar et al 2019;Binashikhbubkr et al 2023). On the other hand, an investigation managed by Griffiths et al (2017) focused on the morphological relationships of 4 fish species in the Scombridae family found in Australian waters.…”