NORFOLK ISLAND — Diseased corals on Norfolk Island have increased threefold since March 2025. Pollution and a federal dredging project threaten unique coral species found only in this location.

Norfolk Island is home to coral species found nowhere else, with approximately 40% of the corals on Norfolk Island and Lord Howe Island believed to be unique. Most of these corals are likely to be undescribed species. Tom Bridge, a coral taxonomist at the Queensland Museum and James Cook University, stated, "These corals are at a really high risk of extinction – but it is a silent extinction because they're not even described [in the scientific literature]."

Pollution and sediment runoff from cattle farming, cleared land, and wastewater have been identified as contributors to widespread disease and algae outbreaks affecting the corals. Water monitoring conducted by CSIRO indicates that pollutants likely originate from cattle manure, wastewater management facilities such as septic tanks, and fertilizer. Bill Leggat, a coral expert at the University of Newcastle who has monitored Norfolk Island's corals and the disease outbreak for five years, noted that 30% to 50% of corals on the island displayed disease symptoms over the past five years. Leggat commented, "The main issue is the nutrients that increase coral disease and then algal growth that puts more stress on the corals."

In April 2025, the federal infrastructure department received environmental approvals to dredge a channel to improve access to Kingston Pier. Rock wall repairs for the Kingston Pier project are anticipated in the coming months, with dredging to follow. The federal infrastructure department intends to award a contract for the project works in August. The Kingston Pier project's conditions include limiting dredging to a 0.5-hectare footprint, disposing of spoil on land, and real-time water quality monitoring. Independent specialists are slated to oversee monitoring to safeguard the surrounding reef and marine environment.

Professor Tracy Ainsworth of the University of New South Wales said, "That is everything that you can do to kill corals." She added, "It is too much for corals to survive." Leggat further stated, "We could rapidly lose the coral reefs and we won't get them back." Bridge also remarked, "If you lose them, they are not coming back." Norfolk Island's corals are isolated, which limits their ability to re-spawn due to an absence of neighboring reefs.

The Norfolk Island regional council has indicated that septic systems, wastewater, stormwater, and other activities require ongoing management to protect water quality. New strategies for managing waterways and cattle grazing are under development on the island. A working group, comprising representatives from multiple government agencies, has been established to coordinate water quality management.