Norfolk Island corals face disease, El Niño and approved dredging

Coral reefs around Norfolk Island show a three-fold increase in disease since March, according to monitoring by University of Newcastle researcher Bill Leggat. Leggat said white syndrome disease begins as a white spot that expands, killing coral tissue and exposing the skeleton.

He attributed the spread to nutrients from cattle manure, septic systems and fertiliser that wash into the lagoons during rain. University of New South Wales researcher Tracy Ainsworth said 30 to 50 percent of corals have shown disease symptoms over the past five years.

She noted that an emerging El Niño could raise water temperatures and increase bleaching risk.

Dredging approval The federal infrastructure department received environment approvals in April 2025 to dredge a channel at Kingston Pier. The project aims to deepen and widen access for larger vessels, with dredging scheduled after rock wall repairs. Conditions limit dredging to a 0.5 hectare area, require land disposal of spoil and mandate real-time water quality monitoring.

Coral isolation Queensland Museum researcher Tom Bridge said about 40 percent of corals at Norfolk and Lord Howe islands are likely found nowhere else. He added that small, isolated populations have limited ability to recover from losses. A Norfolk Island regional council spokesperson said new strategies for waterway and grazing management are in development.

A multi-agency working group has been formed to coordinate water quality efforts.