Pacific Bluefin Tuna Thunnus orientalis From Taiwanese and New Zealand Waters Constitute a Homogeneous Population As Inferred from Molecular Markers

Tissue samples of Pacific bluefin tuna were collected from Taiwanese (n = 53) and New Zealand (n = 70) waters to determine their genetic diversity. Forty specimens from each sample set were selected randomly for sequence analyses of the cytochrome b (Cyt b) gene and the non-coding D-loop. A NJ tree of the Cyt b gene was shallow, revealing a monophyletic topology. A NJ tree of the D-loop showed non-significant geographical grouping, with mean nucleotide diversity 0.032±0.004. Seven microsatellite loci were scored in all specimens and expressed high diversities in both samples. Nei's genetic identity, F_ST and R_ST between two sets of samples were 0.971, 0.003 (p = 0.243) and 0.019 (p = 0.099), respectively. A factorial correspondence analysis showed that the two sets of samples have almost overlapping distributions, and indicate that T. orientalis from New Zealand and Taiwanese waters have high genetic homogeneity.