The oceanographic isolation of the Ogasawara Islands and genetic divergence in a reef‐building coral

The Ogasawara Islands exhibit significant oceanographic isolation, leading to substantial genetic divergence in the reef-building coral Galaxea fascicularis. This study reveals that the coral population in Ogasawara is highly differentiated from its nearest neighbors, primarily due to limited and asymmetric eastward migration from the Ryukyu Islands. Using a combination of population genetics, demographic modeling, and inverse particle tracking based on oceanographic data, researchers confirmed that long-distance larval dispersal—exceeding 44 days—is the only plausible mechanism for gene flow into Ogasawara, with no reciprocal dispersal. These findings underscore the archipelago's role as a dispersal sink and highlight its importance for marine conservation, alongside its recognized terrestrial significance.

Wepfer, P. H., Nakajima, Y., Fujimura, A., Mikheyev, A. S., Economo, E. P., & Mitarai, S. (2022). The oceanographic isolation of the Ogasawara Islands and genetic divergence in a reef‐building coral. Journal of Biogeography, 49(11), 1978–1990. Portico. https://doi.org/10.1111/jbi.14475