Population structure of yellowfin tuna (Thunnus albacares) in the western Pacific Ocean, inferred from microsatellite loci
Appleyard, S.A.; Grewe, P.M.; Innes, B.H.; Ward, R.D. (2001). Population structure of yellowfin tuna (Thunnus albacares) in the western Pacific Ocean, inferred from microsatellite loci. Mar. Biol. (Berl.) 139(2): 383-393. http://dx.doi.org/10.1007/s002270100578
In: Marine Biology: International Journal on Life in Oceans and Coastal Waters. Springer: Heidelberg; Berlin. ISSN 0025-3162; e-ISSN 1432-1793, more
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| Authors | | Top |
- Appleyard, S.A.
- Grewe, P.M.
- Innes, B.H.
- Ward, R.D.
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| Abstract |
Five polymorphic microsatellite loci were examined in 1391 yellowfin tuna (Thunnus albacares) from eight regions of the western (Coral Sea, eastern Australia, Fiji, Indonesia, Philippines and Solomon Islands) and eastern (California and Mexico ) Pacific Ocean. Across all samples, numbers of alleles per locus ranged from 7 to 30 (mean: 17.0), and observed heterozygosities per locus ranged from 0.223 to 0.955 (mean: 0.593). Temporal collections were available for three areas: no significant temporal heterogeneity was observed for the Coral Sea (1991/1992 and 1995/1996 collections) or eastern Australia (1994/1995, 1995/1996, 1996/1997 and 1997/1998), but there was slight but significant heterogeneity at one locus (cmrTa-161) between the two Philippines collections (1994/1995 and 1996/1997). Genotypes generally showed a good fit to Hardy–Weinberg expectations within populations; only cmrTa-208 in the pooled Coral Sea population gave a significant deviation after Bonferroni correction for 40 tests, with a small but significant excess of homozygotes. Four loci showed no evidence of population differentiation following contingency Chi-squared and F ST analyses. The fifth locus, cmrTa-161, showed small but significant differentiation (F ST=0.002, P<0.001). This heterogeneity was largely a result of the Philippines 1994/1995 and Fiji collections; there was no correlation with geographic distance. The average F ST across all five loci was very low (F ST=0.002), but it was significant (P<0.001). It is unclear whether this low but significant differentiation reflects noise in the dataset, perhaps arising from experimental error, or real population differentiation. The finding of very limited population heterogeneity accords with most of the earlier allozyme and mitochondrial DNA studies of yellowfin tuna in the Pacific Ocean. |
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