Spirals That Save Reefs
Coral reefs are declining worldwide, and one major challenge is that baby corals rarely survive long enough to settle and grow. Although a single coral can release millions of larvae, almost all die before finding a safe spot to attach. To help them, researchers at the Hawaiʻi Institute of Marine Biology developed and tested a series of 3D-printed settlement modules featuring different shapes inspired by natural reef habitats. One shape—small spiral pockets called helix recesses—stood out dramatically.
In a year-long field test in Kāneʻohe Bay, these helix recesses attracted about 80 times more coral settlers than other designs and helped them survive 20–50 times better. They even outperformed nearby natural reef surfaces. The researchers also found that high-flow water conditions boosted settlement further, highlighting the role of tiny currents in guiding larvae into the recesses.
This simple, scalable design could make coral restoration faster, cheaper, and far more effective as reefs face accelerating climate change.
