Diel movement patterns and abundance of the sea urchin Tripneustes gratilla with comparisons to Echinometra mathaei and their associated ecology at Ningaloo Reef, north-western Australia

A study on the Ningaloo Coast reveals that the sea urchin Tripneustes gratilla exhibits higher movement patterns and feeding activity at night, with significant grazing impact on macroalgal communities. Researchers found that most T. gratilla were in the 60-70 mm size range, showing gut content peaks in the morning, suggesting nocturnal feeding behavior. Compared to Echinometra mathaei, T. gratilla displayed greater movement regardless of site or time, with both species peaking in activity at night or evening. The study recommends regular monitoring of urchin and macroalgal populations due to T. gratilla's potential localized pressure on reef ecosystems.

Bessey, C., Scurfield, E., Mortimer, N., Hellmrich, L., Crossing, R., & Keesing, J. K. (2025). Diel movement patterns and abundance of the sea urchin Tripneustes gratilla with comparisons to Echinometra mathaei and their associated ecology at Ningaloo Reef, north-western Australia. Marine Environmental Research, 212, 107528. https://doi.org/10.1016/j.marenvres.2025.107528