Distinct Yellowfin Tuna (Thunnus albacares) Stocks Detected in Western and Central Pacific Ocean (WCPO) Using DNA Microsatellites

Abstract

The yellowfin tuna, Thunnus albacares (Bonnaterre, 1788), covers majority of the Philippines’ tuna catch, one of the major fisheries commodities in the country. Due to its high economic importance sustainable management of these tunas has become an imperative measure to prevent stock depletion. Currently, the Philippine yellowfin tuna is believed to be part of a single stock of the greater WCPO though some reports suggest otherwise. This study therefore aims to establish the genetic stock structure of the said species in the Philippines as compared to Bismarck Sea, Papua New Guinea using nine (9) DNA microsatellite markers.DNA microsatellite data revealed significant genetic differentiation between the Philippine and Bismarck Sea, Papua New Guinea yellowfin tuna samples. (FST = 0.034, P = 0.016), which is further supported by multilocus distance matrix testing (PCoA) and model-based clustering (STRUCTURE 2.2).With these findings, this study posits that the yellowfin tuna population in the Philippines is a separate stock from the Bismarck Sea population. These findings add evidence to the alternative hypothesis of having at least 2 subpopulations of yellowfin tuna in the WCPO and calls for additional scientific studies using other parameters to investigate this. Accurate population information is necessary in formulating a more appropriate management strategy for the sustainability of the yellowfin tuna not only in the Philippines but also in the WCPO.

Putting all the pieces together: integrating current knowledge of the biology, ecology, fisheries status, stock structure and management of yellowfin tuna (Thunnus albacares)

“…These results are consistent with those obtained from tagging studies in the north EPO and collectively support the assumption that YFT display site fidelity (Schaefer et al 2007(Schaefer et al , 2011. The possible existence of different sub-populations has also been detected within the central PO using the mtDNA COI gene sequences (Li et al 2015), and between the central and western regions of the PO, using ten microsatellite loci (Aguila et al 2015). Significant genetic differentiation has also been revealed among sites in the north-western IO, using both the mitochondrial ATPase 6 and 8 regions (498 bp) and two microsatellite loci (Dammannagoda et al 2008).…”

“…In contrast, a few recent studies completed for the IO and PO have looked at YFT population structure at a much smaller scale than previously considered for stock assessments and management strategies (Dı ´az-Jaimes and Uribe-Alcocer 2006; Dammannagoda et al 2008;Kunal et al 2013;Aguila et al 2015;Li et al 2015). The analysis of seven simple sequence repeat loci showed significant differentiation between 2015) confirmed the presence of two distinct populations in the EPO and WCPO.…”

RETRACTED: Close Kin Proximity in Yellowfin Tuna (Thunnus albacares) as a Driver of Population Genetic Structure in the Tropical Western and Central Pacific Ocean

“…Numerous types of studies have detected some level of genetic differentiation in yellowfin populations within the Pacific Ocean. Morphometric calculations have been used to propose semi-independent eastern, central, and western populations (Suzuki et al, 1978); allozymes differentiated fish caught in the western and central Pacific from eastern fish (Ward et al, 1997); microsatellites detected structure between the Philippines and Papua New Guinea (Aguila et al, 2015); and genome-wide single nucleotide polymorphisms (SNP) distinguished fish from eastern and central Pacific, and to a lesser degree central from western Pacific regions (Grewe et al, 2015). Some of the same studies did not detect structure in sympatric species, like skipjack, at the same intra-ocean scale and using the same molecular markers (Ely et al, 2005).…”

The population genomics of yellowfin tuna (Thunnus albacares) at global geographic scale challenges current stock delineation

“…The evidence of within-ocean population genetic structure was recently shown in three different studies that used potentially adaptive SNPs 3 , mitochondrial DNA sequences 20 and neutral microsatellites 21 . Using putatively adaptive loci selected from among sequences obtained by reduced-representation libraries and genotyping-by-sequencing through a proprietary Diversity Arrays Technology protocol, DArTseq™, Grewe et al .…”