Population differentiation across small distances in a coral reef-associated vermetid (Ceraesignum maximum) in Palau
Despite being one of the world’s leading countries in coral reef conservation and management, very little data exist for coral reef-associated species in the island nation of Palau, hampering managers’ ability to more effectively protect coral reef ecosystems. Here we examine populations of the vermetid Ceraesignum maximum, a common species on coral reefs, with short or absent pelagic larval stage, in order to elucidate patterns of gene flow within Palauan reefs. We collected specimens (n = 582) from 20 sites across Palau. Cytochrome oxidase subunit I analyses show private haplotypes at all sites examined, with a clear separation between outer and inner reef locations, and a unique population within isolated Nikko Bay. Oceanographic isolation between the waters of Nikko Bay, inner and outer reefs may contribute to our observed genetic differentiation. Our results indicate past demographic expansion of C. maximum across the region and also indicate that multiple sites of both inner and outer reef locations would need to be protected to conserve this species’ genetic diversity, including unique Nikko Bay. These results demonstrate the utility of C. maximum as a good species to investigate gene flow across small scales (< 10 km) as seen in Palau.
KeywordsMollusca Population genetics mtDNA COI Connectivity
The authors thank Dr. Rob Toonen and Anuschka Faucci (Hawai’i Institute of Marine Biology) for the initial idea of utilizing Ceraesignum in population genetic analyses. Arius Merep (Palau International Coral Reef Center; PICRC) is thanked for the acquisition of some specimens, and the other staff at PICRC are thanked for their help with logistics. Zoe Kintaro, Minelli-Rain Olkeriil, Leah Marie Bukurou, Bill Tony, Blesam Tarkong, Skarlee Renguul, Kaitlin Ord Isalias, Zacateca Adelbai and Nelson Masang, Jr. (all Palau Community College; PCC) are thanked for laboratory help. This work was funded under the SATREPS scheme supported by the Japan Science and Technology Agency (JST) and the Japan International Cooperation Agency (JICA) as part of the P-CoRIE project between the University of the Ryukyus, PICRC, and PCC. IF-S was supported by a Marie Curie Action of the European Union's Seventh Framework Programme (FP7/2007–2013) under REA Grant Agreement 600391 (FELLOWSEA: Campus do Mar International Fellowship Program). Comments from two anonymous reviewers greatly improved an earlier version of the manuscript.
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Conflict of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
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