EAPSI: Investigating the Role of Peripheral Habitats in the Adaptive Potential of Coral Reef Fishes

Roberts May B, Santa Cruz CA

Investigators

Abstract

Coral reef organisms and habitats are faced with a growing number of stressors, the effects of which are increasingly monitored and studied. Less is understood about the underlying genetics, the evolutionary tools for species to adapt and persist through some of these environmental changes. This study aims to identify whether the potential for local adaptation differs across populations within a species range by examining particular genetic characteristics in multiple coral reef fish species. Researchers will compare between populations of fishes at the center of their species range and those at the edges of the species range to test whether peripheral habitats may serve as regions harboring populations with greater adaptive potential. For this project, fish populations at their northern range boundary in the temperate coral reefs of Japan will be compared to populations at the center of their ranges in the tropical reefs of the Philippines and Indonesia. This study aims to increase understanding about the role of edge populations in local adaptation and speciation as well as to gain information to better predict the vulnerability of these species to changes in climate and environment. This research will be conducted under the mentorship of molecular biologist, Dr. James Reimer at the University of the Ryukyus. Dr. Reimer has valuable experience and insight on the population genetics of the marine system in this region and provides access and instruction to key field equipment and laboratory techniques. This project will consist of the collection of the edge population samples for eight reef fish species in Japan, subsequent DNA extractions, sequencing and finally, analyses. Study species were chosen in part, based on their distribution location and size, reproductive mode, and pelagic larval duration. Researchers suspect that these life history characteristics influence potential patterns in the targeted genetic indicators of adaptation and speciation. Samples collected during this study will be compared with previously collected Philippine and Indonesian samples. Using information generated from RAD sequencing of both population types, researchers will compare levels of genetic variation and the frequency of genes under selection between center and peripheral populations of each species. The findings from this research will help to answer whether these particular indictors of adaptive potential differ between populations within a species range in these reef fish. Further studies can then be conducted to better understand mechanisms of speciation, local adaptation, rapid evolution, as well as to improve the accuracy of future predictions for coral reef health. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Japan Society for the Promotion of Science.