Lessons from two major coral reef reports for Norfolk Island
We know that Norfolk Islanders have been worrying about the health of Emily and Slaughter Bays for decades. In 1988, after local people raised concerns about declining fish, damaged corals and water quality, marine biologist Angela Ivanovici surveyed the lagoon. She recommended long-term monitoring and warned that Emily and Slaughter Bays could not be managed separately from the catchment that drains into them (Ivanovici, 1988).
Nearly forty years later, two major coral reef reports released within weeks of each other have made me think again about that advice. One draws on 40 years of monitoring on the Great Barrier Reef; the other is the largest global assessment of coral reefs ever assembled. Their central message is highly relevant to Norfolk Island: reefs can recover when pressures ease, but the time available for recovery is shrinking as climate-driven disturbances become more frequent.
That makes the pressures we can control here – water quality, nutrients, sediment, wastewater and runoff – more important, not less.
What the new reports add
Some of the healthy coral in the Kingston lagoon, Norfolk Island. These spots are becoming harder to find
Increasingly, areas of Kingston Lagoon look like this – covered in algae
The Global Coral Reef Monitoring Network (GCRMN) reports that global hard coral cover has declined substantially from its 1980–2009 reference period, with the largest single-year loss on record occurring between 2023 and 2024. More importantly for this story, the intervals between major disturbances are becoming shorter. Where reefs once might have had around a decade to recover, in many regions that window is now only five or six years (González-Rivero et al., 2026).
That 1980 reference period is not a picture of pristine reefs. The report cautions that it almost certainly already includes degraded reefs (González-Rivero et al., 2026). It is a useful nod to shifting baseline syndrome – the way each generation can unknowingly accept a progressively altered environment as normal (Soga & Gaston, 2018). I wrote about this phenomenon in 2024 in Then and now – shifting baseline syndrome laid bare. On Norfolk Island, our systematic underwater record before the 1980s is thin. Ivanovici herself found there was too little historical information to determine whether coral or fish populations had deteriorated, which is precisely why she recommended repeated monitoring (Ivanovici, 1988).
There is still room for hope. Global hard coral cover increased after the third global bleaching event when disturbances eased (González-Rivero et al., 2026). We saw a small, local hint of that possibility during the drought of 2024 and early 2025 (see Glimpses of recovery: what the reef could be if we let it). Anecdotally, I began seeing less disease in some places, better coral growth and more fish activity. I cannot prove reduced runoff caused those improvements, and drought is certainly not something to wish for on a rain-dependent island. But the timing was consistent with a simple proposition: when some pressures ease, reefs may get breathing space.
The AIMS annual report tells a similar story. After severe losses associated with the 2024 bleaching event, its 2025–26 surveys found the beginnings of recovery across much of the Great Barrier Reef. Heat stress was lower than in the previous two summers, and late-summer cloud and cooler water helped limit bleaching. It was a partial reprieve rather than a return to normal, but it gave many reefs some room to recover (AIMS LTMP, 2026).
The 40-year AIMS record is what makes that conclusion possible. It also shows why coral cover alone is not enough: the 2024 bleaching event changed coral communities unevenly, with fast-growing, bleaching-sensitive Acropora among the groups most heavily affected. The GCRMN report adds another warning sign: macroalgal cover has increased globally, and at local scales algae can occupy the space where new corals need to settle (AIMS LTMP, 2026; González-Rivero et al., 2026).
What we already know about Norfolk Island
Norfolk Island now has six years of formal, standardised reef-health monitoring. The March 2026 Norfolk Island Lagoonal Reef Ecosystem Health Assessment records increasing turf algae, reduced bare substrate for coral recruitment, prolonged disease affecting dominant reef-building Acropora and Montipora, and repeated exposure to sedimentation, freshwater and nutrient inputs following major rainfall events. Disease prevalence was reported at 30–75% of colonies across inshore sites. By contrast, the offshore reference reef at Elephant Rock had much higher coral cover, lower algal abundance and no evidence of coral disease (Ainsworth et al., 2026).
Alongside that formal work, I have a citizen-science photographic record going back to January 2020 – around 170,000 underwater images. It is not a substitute for a standardised monitoring program, but repeated photographs of the same places can document changes that shorter field programs may miss, and I am drawing on that archive for one of my PhD chapters.
Peer-reviewed research fills in more of the picture. Page, Ainsworth, et al. (2023) detected terrestrially derived dissolved inorganic nitrogen on our near-shore reefs – forms of nitrogen such as nitrate, nitrite and ammonium that can act rather like fertiliser in the marine environment. Exposure was linked to rainfall, catchment inputs and the extent to which near-shore water mixed with cleaner open-ocean water. Vanderzalm, Currie, et al. (2024) used microbial source tracking to identify both human and animal sources of faecal contamination, including human wastewater markers in groundwater after rainfall. Page, Leggat, et al. (2023) documented a severe Montipora disease outbreak after heat stress and pollution events, affecting about 60% of surveyed colonies in 2020–21. Ho et al. (2025) have also documented coral–algal interactions and seasonal blooms with potential links to degraded water quality, while cautioning that the specific causes require further investigation.
None of that means every patch of algae or diseased coral can be traced to one pipe, paddock or landholder. Reef ecosystems are not that simple. Nor does it justify attributing every problem to climate change. Rainfall itself is not a pollutant. Sediment, nutrients, sewage-derived contamination and animal waste are picked up or mobilised as water moves through the landscape. We cannot control the rain, but we can do a great deal about what it carries to the reef (Vanderzalm, Golding, et al., 2024).
Kingston Common from Flagstaff Hill, late nineteenth century. Colonial drainage channels are visible across the swamp at centre left; modifications to drain this wetland for agriculture and construction began as early as 1789.
NSW Government Printing Office collection, State Library of New South Wales, GPO2 – 52035. Possibly A. Dyer, April 1884; attribution provisional.
This is not about blaming the past
The Kingston lowlands have been drained, grazed, cultivated, built on and modified for generations. Colonial settlers brought with them a perfectly ordinary approach to wet ground: drain it and make it useful. The Pitcairn settlers continued to manage the landscape for the same practical reasons. Ivanovici records that Water Mill and Town creeks were modified during the second penal settlement and straightened again after major flooding in the 1930s. The draft Waterway and Wetland Management Strategy notes that a channel had been cut near the Lime Kiln as early as 1789 to drain the wetland covering much of what is now Kingston Common (Ivanovici, 1988; Norfolk Island Regional Council, 2026).
Septic systems and drains were accepted land-management tools. Those decisions were not made with twenty-first-century knowledge of catchment-to-reef connectivity, coral disease ecology or climate-driven changes to wetland hydrology. What has changed is what we know, and the environmental conditions in which those old systems now operate.
Acid sulfate soils are a good example. Climate change did not create them. Sulfur-rich materials occur naturally in some of Norfolk Island’s peat and waterlogged sediments. When those soils remain saturated, oxygen is excluded. When they dry or are disturbed, sulfides can oxidise, producing sulfuric acid and mobilising metals that may later move into waterways (Fitzpatrick et al., 2023).
A hotter, generally drier climate increases the risk that vulnerable wetlands dry out. Current local planning therefore includes protecting and rehydrating acid-sulfate-soil-prone wetlands, maintaining water levels during dry periods and modifying drains that unnecessarily expose vulnerable soil layers (Norfolk Island Regional Council, 2026). A drain once regarded as an improvement can become a liability under different climatic conditions. The question is not who should have known better generations ago. It is what we do with the evidence we have now.
Water quality is one pressure we can reduce
Norfolk Islanders cannot cool the Pacific Ocean, prevent an El Niño or stop a marine heatwave forming. Reducing local pressure cannot substitute for serious global climate action. But it does not follow that local management is irrelevant. The GCRMN report says reefs under lower local pressure resist and recover from heat stress more effectively. On the Great Barrier Reef, poor water quality has been shown to slow coral recovery and increase susceptibility to disease and crown-of-thorns starfish impacts (González-Rivero et al., 2026; MacNeil et al., 2019).
A 20-year Hawaiian study makes the land–sea connection particularly clear. Reefs with lower land-based impacts such as wastewater pollution and urban runoff had better coral trajectories, and reducing land- and sea-based pressures together produced much better outcomes after a severe marine heatwave than addressing either set of pressures alone (Gove et al., 2023).
Nutrient enrichment can stimulate algal growth and reduce coral tolerance to heat and light stress (D’Angelo & Wiedenmann, 2014; Wiedenmann et al., 2013). Sediment can reduce light, smother benthic organisms and force corals to spend energy clearing their surfaces; the effects depend on how much sediment arrives, how long it remains and how often exposure occurs (Erftemeijer et al., 2012). The same caution applies to what we put on the land. Herbicides are still used within the Kingston catchment, and their potential to reach the lagoon in runoff is another reason land and reef management cannot sensibly be separated.
I think of compounding stress a little like a person being hit by one illness before fully recovering from the last. The next infection does not arrive in a body with full reserves. A coral already coping with poor light, sediment, excess nutrients, disease or algal competition does not enter a marine heatwave with the same physiological margin as a coral under less stressful local conditions. Improving water quality will not make our reef immune to bleaching. It may give surviving corals a better chance to recover afterwards.
Why dredging sediment has to be taken seriously
The planned dredging at Kingston Pier sits within this wider picture. I am not arguing that dredging will inevitably damage the lagoon. The project has been environmentally assessed, conditions have been attached to its approval, and the Public Environment Report’s modelling predicted that sedimentation would remain concentrated around Kingston Harbour, with no sediment plume detected over the nearby lagoon and coral reef areas under the modelled scenarios (Advisian Pty Ltd, 2023).
But modelling does not make sediment biologically irrelevant. The project documents identify sediment plumes and spills as potential marine water-quality impacts, and the coral literature is clear that dredging-related turbidity and sedimentation can affect corals. Meaningful limits need to account for local background conditions, coral assemblages and exposure duration rather than relying on a universal threshold (Erftemeijer et al., 2012).
There is also unfinished business. The environmental approval requires monitoring, trigger values and corrective actions, and the draft Water Quality Management Plan said it would need updating after contractor engagement and final approvals. At the time of writing, I have not been able to find the final operational parameters publicly available – including numerical water-quality and sediment triggers, monitoring locations, stop-work or corrective-action protocols and linked coral-management arrangements (Advisian Pty Ltd, 2023).
Those details determine what happens if turbidity rises, sediment deposition increases or coral monitoring detects an unexpected response. Before dredging starts, the community should be able to see the thresholds, understand what triggers a response, know who can stop or modify work and see how monitoring results will be reported.
The reef beside Kingston is not starting from an unstressed baseline. It is already dealing with disease, algal expansion, nutrient inputs, rainfall-driven sedimentation and recurrent heat stress (Ainsworth et al., 2026). Dredging also cannot be treated as a separate sediment problem from the catchment. There is little sense in tightly controlling a dredging plume while allowing avoidable sediment from eroding drains, bare ground or poorly managed runoff to keep reaching the same receiving environment.
The long game
One of the clearest messages in both new reports is almost mundane: keep monitoring. AIMS has surveyed the Great Barrier Reef for 40 years. That record can distinguish a genuine trend from a good year or a bad year, and it can show recovery, reversal and changes in coral communities that would otherwise be missed (AIMS LTMP, 2026).
Ivanovici made essentially the same point here in 1988. She established five monitoring transects and recommended water-quality monitoring, biological studies and repeated surveys. She also recorded that the major community concern was maintaining good water quality in the bays, with sewage, nutrients, microbiological contamination and sediment all identified as potential threats. Her conclusion was blunt: because Water Mill and Town creeks flow into Emily Bay, management of the bays could not be undertaken in isolation from land-based activities (Ivanovici, 1988).
That was nearly four decades ago. The monitoring we have now cannot disappear when a grant ends, a project finishes or a research team changes. We need a permanent, properly resourced catchment-to-reef program linking rainfall, groundwater, nutrients, microbial contamination, sediment and turbidity with coral condition, disease, algae, recruitment and fish communities. Monitoring is not a substitute for action; it is how we find out whether the action worked.
Kingston, the reef and stewardship
Kingston is usually spoken about through its buildings, archaeology, convict history and cultural landscape. But the sea is part of the setting too. Emily and Slaughter Bays are where people swim, teach children to snorkel, fish, paddle, picnic and take visitors. The reef supports biodiversity and fisheries, and coral reefs more broadly are highly effective natural coastal defences because their structure dissipates wave energy before it reaches the shore (Ferrario et al., 2014).
Its inshore setting adds to both its vulnerability and its value. Near-shore reefs are among those most exposed to land-based pollution and coastal development (Page, Ainsworth, et al., 2023). Norfolk Island still has a coral reef that people can walk to, swim over and know personally. It is not just attractive scenery in front of Kingston. It is habitat, recreation, culture, memory, coastal protection and part of the living setting of the World Heritage landscape.
Norfolk Islanders are not newcomers to this conversation. Local concern prompted the 1988 Ivanovici survey. Community members told her water quality was their major concern, suggested catchment management and monitoring and offered to participate in a volunteer monitoring program. Government agencies have statutory responsibilities and scientists have a responsibility to provide evidence, but stewardship does not belong only to institutions. The people who live here have generations of knowledge of these waters and a long history of adapting local practices when marine resources need protection (Ivanovici, 1988).
An integrated management approach
The global picture is confronting, but it is not one of despair. The GCRMN report explicitly says coral reefs have not crossed a universal point of no return. Recovery remains possible where disturbance intervals allow it, and the AIMS report shows recovery beginning after a year in which heat stress eased. Our own observations suggest Norfolk’s reef can also respond when conditions improve (González-Rivero et al., 2026; AIMS LTMP, 2026).
So the practical task is to reduce the pressures we can control locally while continuing to argue for global action on those we cannot. That means getting serious about wastewater and septic leakage, keeping nutrients and soil out of waterways, protecting and rehydrating vulnerable wetlands, managing cattle access and erosion where they affect water quality, insisting on stringent sediment and light controls around marine works, and maintaining long-term monitoring.
More than anything, it requires an integrated management approach. Wastewater, groundwater, stormwater, wetlands, grazing, erosion, heritage management, port infrastructure and the Marine Park cannot keep being managed as though they stop affecting one another at an administrative boundary. Gove et al. (2023) found that addressing pressures on land and in the sea together produced better reef outcomes after severe heat stress than tackling either in isolation. That is remarkably close to the management problem sitting in front of us at Kingston.
None of this requires us to turn neighbours into villains or rewrite the island’s history as a list of environmental mistakes. The climate has changed, the evidence has changed and management has to change with it.
We are not powerful enough to stop a marine heatwave from Norfolk Island, but we are powerful enough to decide how much additional stress we ask this reef to carry.
In 1988, Norfolk Islanders asked for monitoring, better water quality and catchment management. Nearly forty years later, we have far more evidence, far better science and far less time to waste. The new reports are not telling us that reefs are doomed. They are telling us that recovery time is becoming precious. Our job is to give this reef as much of it as we can.
Looking west from Middle Beach across Slaughter Bay and the Kingston Lagoon to Kingston Pier. Volume 6: Tasmania and Norfolk Island. A collection of watercolour drawings by F. R. Nixon (Bishop of Tasmania) and Anna Maria Nixon, probably 1851. Mitchell Library, State Library of New South Wales
Looking west from Middle Beach across Slaughter Bay and the Kingston Lagoon to Kingston Pier, December 2025
References
Advisian Pty Ltd. (2023). Kingston Pier Channel Construction Project: Public Environment Report. Australian Government Department of Infrastructure, Transport, Regional Development, Communications and the Arts.
AIMS Long-Term Monitoring Program (AIMS LTMP). (2026). Great Barrier Reef Annual Summary Report of Coral Reef Condition 2025–2026. Australian Institute of Marine Science. https://doi.org/10.25845/440g-d478
Ainsworth, T. D., Moir, T., Gaston, T. F., Leggat, W., & Roughan, M. (2026). Norfolk Island Lagoonal Reef Ecosystem Health Assessment, March 2026. Prepared for Marine Parks Management East Section, Marine and Islands Parks Branch, Parks Australia.
D’Angelo, C., & Wiedenmann, J. (2014). Impacts of nutrient enrichment on coral reefs: New perspectives and implications for coastal management and reef survival. Current Opinion in Environmental Sustainability, 7, 82–93. https://doi.org/10.1016/j.cosust.2013.11.029
Erftemeijer, P. L. A., Riegl, B., Hoeksema, B. W., & Todd, P. A. (2012). Environmental impacts of dredging and other sediment disturbances on corals: A review. Marine Pollution Bulletin, 64(9), 1737–1765. https://doi.org/10.1016/j.marpolbul.2012.05.008
Ferrario, F., Beck, M. W., Storlazzi, C. D., Micheli, F., Shepard, C. C., & Airoldi, L. (2014). The effectiveness of coral reefs for coastal hazard risk reduction and adaptation. Nature Communications, 5, 3794. https://doi.org/10.1038/ncomms4794
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González-Rivero, M., Dallison, T., Wicquart, J., Brigdale, A., Logan, M., Fobert, E. K., Staub, F., & Planes, S. (Eds.). (2026). Status of Coral Reefs of the World: 2025. Global Coral Reef Monitoring Network and International Coral Reef Initiative. https://doi.org/10.59387/LFPR6347
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Ho, M. L., Page, C., Leggat, B., Gaston, T., Eckhardt, S., & Ainsworth, T. D. (2025). Anthropogenic impacts on coral-algal interactions of the subtropical lagoonal reef, Norfolk Island. Integrative Organismal Biology, 7(1), obaf004. https://doi.org/10.1093/iob/obaf004
Ivanovici, A. M. (1988). Emily Bay and Slaughter Bay, Norfolk Island: Resources and options for management. Report of 26 June–6 July 1988 survey. Australian National Parks and Wildlife Service.
MacNeil, M. A., Mellin, C., Matthews, S., Wolff, N. H., McClanahan, T. R., Devlin, M., Drovandi, C., Mengersen, K., & Graham, N. A. J. (2019). Water quality mediates resilience on the Great Barrier Reef. Nature Ecology & Evolution, 3, 620–627. https://doi.org/10.1038/s41559-019-0832-3
Norfolk Island Regional Council. (2026). Draft Norfolk Island Waterway and Wetland Management Strategy 2026–2036.
Page, C. E., Ainsworth, T. D., Leggat, W., Egan, S., Sen Gupta, A., Raoult, V., & Gaston, T. F. (2023). Localising terrestrially derived pollution inputs to threatened near-shore coral reefs through stable isotope, water quality and oceanographic analysis. Marine Pollution Bulletin, 193, 115193. https://doi.org/10.1016/j.marpolbul.2023.115193
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Vanderzalm, J., Currie, S., Smith, W., Metcalfe, S., Taylor, N., & Ahmed, W. (2024). Microbial source tracking of fecal pollution to coral reef lagoons of Norfolk Island, Australia. Science of the Total Environment, 912, 168906. https://doi.org/10.1016/j.scitotenv.2023.168906
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Wiedenmann, J., D’Angelo, C., Smith, E. G., Hunt, A. N., Legiret, F.-E., Postle, A. D., & Achterberg, E. P. (2013). Nutrient enrichment can increase the susceptibility of reef corals to bleaching. Nature Climate Change, 3, 160–164. https://doi.org/10.1038/nclimate1661