A new study led by James Cook University Senior Research Officer and Lecturer, and University of New South Wales PhD candidate, Hillary Smith, has examined the effectiveness of coral seeding devices to help corals survive in warming oceans.
The research found that corals seeded onto specialised ceramic devices and placed onto reefs had higher survival rates than corals in natural conditions. Even more corals survived when seaweed was manually removed from reefs.
"Just like planting a seedling in a small flowerpot and plucking weeds, the same strategies seem to benefit baby corals," said Ms Smith.
"Coral seeding devices worked best when paired with sea-weeding, or removal of overgrown macroalgae at this reef."
However, the benefits faded after one year, highlighting the need to refine coral seeding to ensure it is cost-effective and scalable.
She said as coral reefs continue to degrade under human pressure, direct restoration and intervention strategies are evolving quickly, but overcoming high mortality rates in early life stages remains a major challenge.
"Our results show that survival of seeded corals needs to be monitored over multiple years to understand if the method has long-term ecological benefits," said Ms Smith.
"We found that sea-weeding combined with seeding can give young corals a crucial head start, but it's not a silver bullet. Long-term survival depends on many site-specific factors, and restoration strategies need to be tailored accordingly."
Although seeding devices initially outperformed natural coral survival, costs remain a barrier.
"This area of research is rapidly developing and it's possible that new device designs, more efficient coral aquaculture processes, and novel deployment technologies could boost survival outcomes to reduce the cost of coral seeding," said Ms Smith.
This project was a collaboration between UNSW, JCU, and the Australian Institute of Marine Science (AIMS). Macroalgae were removed by citizen scientists as part of an ongoing joint project between JCU and Earthwatch Australia, funded by Mitsubishi Corporation.
AIMS co author Dr Cathie Page was supported by the Australian Coral Reef Resilience Initiative (ACRRI), which is jointly funded by AIMS and BHP.
Link to paper here.
