Composition of green turtle feeding aggregations along the Japanese archipelago: implications for changes in composition with current flow
- 455 Downloads
In order to develop effective conservation strategies for endangered migratory species, the link between feeding and breeding grounds needs to be clarified. In this study, the genetic compositions of consecutive Japanese feeding aggregations of green turtles (Chelonia mydas) along the Kuroshio Current were examined by mixed-stock analyses of mitochondrial DNA control-region sequences. The results indicated that the southern feeding aggregation around Yaeyama (24.3°N, 124.0°E) was sourced from various Pacific rookeries in the Yaeyama, Ogasawara, Western Pacific, and Indian Oceans and Southeast Asia. Among northern feeding aggregations, the Ginoza (26.5°N, 128.0°E) aggregation was also sourced from the Western Pacific Ocean, but the Nomaike (31.4°N, 130.1°E), Muroto (33.2°N, 134.2°E), and Kanto (35.6°N, 140.5°E) aggregations were contributed mostly by the closer Ogasawara rookeries. The reduced contribution from tropical Pacific rookeries to northern feeding aggregations and the significant correlation between genetic differentiation and geographical distance matrices of feeding aggregations indicated that most hatchlings from these regions transported by the Kuroshio Current settle in upstream feeding grounds along the Japanese archipelago, implying that current flow influences the composition of feeding aggregations. Differences in the composition of relatively close neritic feeding aggregations have important conservation implications, for which both regional and multinational conservation strategies are needed.
KeywordsMarkov Chain Monte Carlo Haplotype Frequency Green Turtle Kuroshio Current Feeding Ground
We would like to acknowledge the followings for providing information about the stranded turtles on Ishigaki Island and field sampling assistance in Yaeyama Islands: the member of the Ishigaki Island Sea Turtle Research Group; K. Okuzawa and the staff of the Ishigaki Tropical Station and Yaeyama Station, Seikai National Fisheries Research Institute; D. Imakita (Faculty of Agriculture, Kinki University); and Y. Kawabata, T. Yasuda, K. Ichikawa, and H. Watanabe (Graduate School of Informatics, Kyoto University). The staff of the Ogasawara Marine Center and fisheries cooperative associations in Hahajima Island and Chichijima Island and M. Kaneko (Club Noah Hahajima) kindly helped with sampling in Ogasawara Islands. Sampling in Ginoza was supported by N. Kamezaki and the Sea Turtle Association of Japan. M. Kinoshita, H. Sawada (Graduate School of Agriculture, Kyoto University), R. Matsuoka, and T. Nishizawa (IREIIMS, Tokyo Women’s Medical University) provided assistance with the DNA extraction, amplification, and sequencing analyses. T. Hamabata and H. Koike (Graduate School of Social and Cultural Studies, Kyushu University) kindly provided data on the Muroto and Nomaike aggregations. We thank the two anonymous reviewers for valuable comments on this manuscript. This study was partly supported by a Grant-in-Aid for JSPS Fellows (J.O. 17-1976), for Research Activity Start-up (J.O. No. 19880017), for Young Scientists B (J.O. No. 22710236), and the Global COE Program, Informatics Education and Research for a Knowledge–Circulating Society.
- Bowen BW, Bass AL, Chow S-M, Bostrom M, Bjorndal KA, Bolten AB, Okuyama T, Bolker BM, Epperly S, Lacashella E, Shaver D, Dodd M, Hopkins-Murphy SR, Musick JA, Swingle M, Rankin-Baransky K, Teas W, Witzell WN, Dutton PH (2004) Natal homing in juvenile loggerhead turtles (Caretta caretta). Mol Ecol 13:3797–3808CrossRefGoogle Scholar
- Excoffier L, Laval G, Schneider S (2005) Arlequin ver. 3.0: an integrated software package for population genetics data analysis. Evol Bioinform Online 1:47–50Google Scholar
- Hamabata T, Nishida S, Kamezaki N, Koike H (2009) Genetic structure of populations of the green turtle (Chelonia mydas) in Japan using mtDNA control region sequences. Bull Grad School Soc Cult Stud Kyushu Univ 15:35–50Google Scholar
- IUCN (2010) IUCN red list of threatened species. Version 2010.4. Accessed on 14 Mar 2011. http://www.iucnredlist.org
- Moritz C, Broderick D, Dethmers K, FitzSimmons N, Limpus C (2002) Population genetics of Southeast Asian and Western Pacific green turtles, Chelonia mydas. Final report to UNEP/CM0053Google Scholar
- Musick JA, Limpus CJ (1997) Habitat utilization and migration in juvenile sea turtles. In: Lutz PL, Musick JA (eds) The biology of sea turtles. CRC Press, Boca Raton, pp 137–163Google Scholar
- Nishizawa H, Okuyama J, Kobayashi M, Abe O, Arai N (2010) Comparative phylogeny and historical perspectives on population genetics of the Pacific hawksbill (Eretmochelys imbricata) and green turtles (Chelonia mydas), inferred from feeding populations in the Yaeyama Islands, Japan. Zool Sci 27:14–18CrossRefGoogle Scholar
- Pella J, Masuda M (2001) Bayesian methods for analysis of stock mixtures from genetic characters. Fish Bull 99:151–167Google Scholar