James Cook University undertook sampling of corals at 17 reefs throughout the Coral Sea Marine Park (CSMP) and 17 reefs on the outer shelf of the Great Barrier Reef Marine Park (GBRMP) between February 2019 and March 2020.

The study compared juvenile coral densities and their relationships with local abundance of adult congenerics at geographically isolated reefs within the CSMP versus highly connected reefs within the GBRMP.

This study revealed that juvenile corals were much less (42% less) abundant on isolated reefs in Australia’s CSMP, compared with more spatially proximal outer shelf reefs of Australia’s GBRMP.

Comparatively low abundance of juvenile corals in the CSMP is likely a result of a combination of factors, but low adult coral cover found at many reefs is likely limiting local larval production and supply. This may be further compounded by limited connectivity among the widely separated reefs in the CSMP, constraining larval supply from external sources.