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Norfolk Island's Reef

Discover a fragile paradise – Norfolk Island's beaches, lagoons and coral reef
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    • Algae
    • Corals
    • Eels
    • Everything Else
    • Kingston, Norfolk Island
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    • Sharks
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  • Out on a swim - blog
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Out on A Swim

‘Out on a swim’ is a coral reef blog that tells the stories of the characters who live under the waves and what has caught my eye when ‘out on a swim’ in the lagoons of Norfolk Island. It is also a record of the difficulties Norfolk Island’s reef faces, like many others around the world, as a result of the poor water quality that has been allowed to flow onto it.

This page shows the most recent blog posts. For the complete catalogue, visit the ‘Out on a swim index’ page.

This blog is rated in the Top 20 Coral Reef Blogs in the world.

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I wrote about this massive coral in a blog post ‘The Ancient Massives’, 20 March 2022

Warning signs: quiet and unnoticed collapse of two coral colonies

June 12, 2025

Day 5 of my blog series for the UN Ocean Conference: two long-lived coral colonies in Norfolk’s lagoon died quietly from disease. No drama – just slow collapse and overgrowth by algae. A reminder that not all reef losses are loud, but they are happening.

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In Environmental degradation Tags UNOceanConference, UNOC2025, Coral disease, corals, coral health, water quality
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Lone Pine, Emily Bay, Norfolk Island

Warning signs: coral disease takes hold

June 10, 2025

In Day 3 of this blog post series, published while leaders gather at the UN Ocean Conference in Nice, we see Norfolk Island’s coral reef lagoon quietly delivering a stark warning: recurrent land-based pollution, coral disease, and delayed decisions are dismantling this ecosystem in real time.

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In Environmental degradation Tags UNOC2025, UNOceanConference, Coral disease, Reef health, coral reef, water quality, marine conservation, ocean action, Environmental protection, ocean science
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An Acropora coral colony, Emily Bay, Norfolk Island, showing early signs of growth anomalies

Warning signs: coral growth anomalies – the slow cancers of the reef

June 9, 2025

Day 2’s post coinciding with the UN Ocean Conference looks at coral growth anomalies – sometimes called coral ‘cancers’. These slow-moving diseases quietly weaken coral colonies, making them far more vulnerable to storm damage and algal takeover. On Norfolk Island’s reef, I’ve watched this exact process play out over several years. This is how chronic stress silently dismantles coral ecosystems.

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In Environmental degradation Tags UNOceanConference, Coral disease, coral reef, water quality, coral cancer
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Slaughter Bay, Norfolk Island, March 2020

From 'Watch' to 'Warning'

January 26, 2025

Last week, the chance of coral bleaching in Norfolk Island’s inshore lagoons was raised from ‘Watch’ to ‘Warning’ and will more than likely rise to Alert levels one and two in coming weeks. So why do I worry about water quality all the time when bleaching seems inevitable these days and so the reef is probably doomed anyway? Read on to find out.

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In Corals Tags corals, coral bleaching, heatwave, resilience, water quality, Norfolk Island
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Emily Bay at low tide, early morning, December 2024

A year in review – 2024 on Norfolk Island’s Reef

December 27, 2024

It is five years since I began wielding a camera underwater in Norfolk Island’s lagoons and my third ‘year in review’ for this ‘Out on a swim’ blog. And what a journey it has been. At least this year I have some great news to report, but – a bit like a curate’s egg (partly bad and partly good) – there are also some downers. Find out what 2024 has meant for Norfolk Island’s reef.

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In Environmental degradation Tags Norfolk Island, coral reef, corals, coral health, water quality, environment, environmental protections
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High tide and pounding waves on Norfolk Island’s coral lagoon, southern shore, looking east towards Point Hunter

Norfolk Island reef's autopsy reports

March 3, 2024

More reports to add to a long catalogue of reports were delivered to the general public over the last few days on Norfolk Island’s water quality and reef health. Reassuringly, they all say the same thing. Our poor water quality is affecting the health of our reef. So the science must be good! So when are we going to do something about it?

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In Environmental degradation Tags water quality, reports, Norfolk Island, coral health, coral disease, World Heritage Area
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Is this Atramentous Necrosis? This January, examples of this disease are popping up across Emily Bay on Norfolk Island

Combine bacteria, fungi, and maybe a sponge = one toxic mess

February 1, 2024

This month, I have increasingly noticed a disease that is presenting differently to the white syndrome that we have sadly become used to seeing. With this disease the coral goes grey-ish black and sometimes looks like it is almost dissolving or melting away. The result is a tragedy for the coral. I talk to coral health researcher Associate Professor Tracy Ainsworth about what is going on.

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In Environmental degradation Tags corals, coral health, coral disease, coral reef, water quality
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Norfolk Island’s inshore reef during low tide and at sunrise

A year in review – 2023 on Norfolk Island's reef

December 29, 2023

Sadly, the year didn’t bring any obvious improvements to Norfolk Island's reef in terms of reductions in incidences of coral disease, or runaway algal growth. And while some fish seem to have departed the scene, another species has re-established its home. Here’s a rundown of what I've been doing during the last four years of observations, and what I've seen happening on our reef in 2023.

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In Ecosystem Tags 2023, Norfolk Island, coral reef, Fish, fish species, water quality, coral health, White syndrome
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My grandson

For the sake of our grandchildren

March 26, 2023

What will my grandson see when he is old enough to snorkel on Norfolk Island’s reef? Will there be anything left as I know it? Or will he think it is all great because of that hoary old phenomenon called ‘shifting baseline syndrome’? This record of all my photos and observations will give him some idea of what we had in our bays in the 2020s.

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In Environmental degradation, Fish species Tags Environment, Environmental protection, water quality, biodiversity, grandchildren, Norfolk Island, Emily Bay
4 Comments

Doris, a week after she was taken into rehab

Doris – just one turtle?

March 24, 2023

Many of the turtles that live in Norfolk Island’s coral-reef lagoons are juveniles. In other words, they are the future of their species, and an important piece in the genetic jigsaw. Yet they seem to fall through the cracks when it comes to being protected by the EPBC Act.

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In Environmental degradation Tags Operation Doris, Turtle rescue, Green sea turtle, water quality, EPBC Act
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A sea mat on the edge of the reef where the waves break, Norfolk Island

A tale of two corals

March 22, 2023

My March focus on Norfolk Island’s reef could almost go on for a full year, there’s so much to write about. But time dictates, so I will confine my efforts to one concentrated effort of randomness! Randomness, because there has been no plan to my posts. They have evolved as the month has progressed. Today I highlight two very different corals commonly seen, but not necessarily common.

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In Corals Tags corals, coral reef, soft coral, hard coral, water quality, biodiversity, IUCN Red List, Vulnerable
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Bubbles of oxygen forming on algae, photobombed by a tiny sea slug, sp, Elysia

Bubble and fizz – a quick guide to coral reef chemistry

March 21, 2023

March is often the warmest month on Norfolk Island’s reef, so it's no surprise that the algae are very busily photosynthesising and flourishing. Yesterday, I noticed that the algae had created a thick carpet of bubbles. As I swam my face was gently brushed by thousands of tingling bubbles, fizzing to the surface. It was quite a sight. And a rather weird sensation. So what is going on here?

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In Environmental degradation Tags Algae, coral reef, corals, photosynthesis, reef chemistry, water quality
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Stunning Emily Bay, Norfolk Island.

Tiptoeing through the government silos

March 19, 2023

In the 1960s we had reports voicing concerns around water quality, but nothing was done. When the Commonwealth of Australia’s EPBC Act came into force in 1999, nothing was done. Surely it is high time the issues of failing and inadequate infrastructure, deficient Norfolk Island laws and unsatisfactory protections were fixed once and for all?

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In Environmental degradation Tags Environment, Environmental protection, government, government policy, environmental protections, water quality, sewerage, coral reef, endemic, threatened species, biodiversity
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A common view of an aatuti as you swim into its territory!

Phase shifts and biodiversity

March 9, 2023

One species that is doing remarkably well on Norfolk Island’s reef as it inexorably transitions from coral-dominated to algal-dominated is the banded scalyfin, Parma polylepis, which is unsurprising as their main food source is algae. The downside is they harass and bully all the other species that come anywhere near their territory, to the detriment of our biodiversity. Find out more here.

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In Biodiversity Tags banded scalyfin, biodiversity, phase shift, coral reef, algae, water quality
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Tiny shells collected from the beach, Norfolk Island 1990s

You don’t always know what you’ve got – ’til it’s gone

March 8, 2023

On Norfolk Island, Australian Marine Parks recently issued a no-take area in our coral reef lagoon habitats. My hope is that with these bans in place, in addition to curbing runaway algal growth, there will be an improvement across the reef ecosystem in a number of different species, with subsequent knock effects for others, including for our molluscs, wrasse and octopus species.

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In Ecosystem Tags Environmental protection, no-take zones, algae, water quality
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The black-mouthed tun snail as it clambered over the reef

The awesome, giant, black-mouthed tun snail

March 3, 2023

When I took my first photographs of the live black-mouthed tun snail (Tonna melanostoma) and posted them on iNaturalist, I had no idea that there were no other – as in none, zip, nada – images of it in the public domain; just one of a broken shell that is housed in the Auckland Museum. This is my featured image for 3 March.

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In Environmental degradation Tags Tonna melanostoma, tun shell, water quality, molluscs
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Bait fish, Emily Bay, Norfolk Island, September 2020

Where have all the bait fish gone?

March 2, 2023

For 2 March I've chosen to feature a ball of bait fish photographed in September 2020. There is something awe-insipring about being encircled by a huge seething mass of tiny fish all moving in unison. It takes your breath away. The question is, where have these bait balls gone?

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In Environmental degradation Tags Environment, Fish, water quality
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Healthy montipora coral on Norfolk Island’s reef

The camera doesn’t lie – looking back over three years of observations

March 2, 2023

After three years of observations, I have a unique library of some 80,000 images recording life in Norfolk Island’s lagoons. So I thought it would be worth spending the month of March looking back to see what has changed in that time and what hasn’t. Each day I will feature a different image. For 1 March I have picked a simple brown coral – a plate coral from the genus montipora. Read on to see what is happening to our montipora now.

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In Environmental degradation Tags environment, corals, coral disease, water quality, coral reef
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Hannah and Trish with Doris

Doris – it takes a village

January 20, 2023

This morning marked the end of a four-month journey for Doris the green sea turtle. From a sick, emaciated turtle with lesions across her shell, and covered with an unhealthy growth of algae, she has been transformed to glossy beautiful health. Hannah slid Doris over the side of the boat and back into the bosom of the ocean, her home. We’ll miss her, but as she swam away, our hearts sang, too. She’s back where she should be.

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In Environmental degradation Tags Green sea turtle, Doris, Turtle rescue, water quality
2 Comments

Remnant reef overgrown with algae, 31 January 2022, Emily Bay, Norfolk Island

Come on in. The water's fine ...

January 31, 2022

As Costa Georgiadis says, nature tells the truth, and we must only look at our reef on Norfolk Island to know its truth. We, as custodians, have not been caring enough for it and now that carelessness is coming home to roost.

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In Environmental degradation Tags corals, coral reef, environment, ecosystems, alagae, pollution, Norfolk Island, Coral disease, water quality
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Older Posts →
Featured
Norfolk’s water quality – when action is reported as outcome
June 15, 2026
Norfolk’s water quality – when action is reported as outcome
June 15, 2026

A recent Australian Government media release presents investment, monitoring and catchment works as progress on Norfolk Island’s water quality. Some of that work is useful, and some of it was badly needed. But activity is not the same as proven improvement. This post looks at Kingston sewerage, wetlands, cattle, acid sulfate soils, groundwater and reef health, and asks whether Emily Bay and Slaughter Bay are actually being better protected.

June 15, 2026
How surgeonfishes got their name
June 14, 2026
How surgeonfishes got their name
June 14, 2026

Surgeonfish are named for the sharp little scalpels near their tails, but on Norfolk’s reef their more useful work happens at the other end. Pencil surgeonfish, bluespine unicornfish and their relatives help browse algae across the reef – a small daily job that becomes very valuable on an algae-rich lagoon reef like ours.

June 14, 2026
A shrimp storm
May 28, 2026
A shrimp storm
May 28, 2026

While setting my research cams last week, I swam into what looked like an underwater snowstorm. It appeared to be the aftermath of a mass moulting event, with large numbers of tiny, translucent shrimp-like exoskeletons drifting together near the surface.

May 28, 2026
Kingston dredging: what happens when a reef does not fit the framework
May 28, 2026
Kingston dredging: what happens when a reef does not fit the framework
May 28, 2026

This correspondence with DCCEEW is about more than one dredging proposal. It is about what happens when an ecologically distinctive place is assessed through standard tools that do not always make its most important values easy to see. I am publishing it here because that is something we need to be aware of, both on Norfolk Island and more broadly in Australia.

May 28, 2026
Kingston dredging: the project advances, the questions remain
May 24, 2026
Kingston dredging: the project advances, the questions remain
May 24, 2026

Kingston dredging is edging closer, and the paper trail is growing. This post brings together earlier correspondence with the Department and the latest media release so readers can see what has been asked, what has been answered, and what still remains unclear about the project, its rationale, and the protections proposed for the reef.

May 24, 2026
The lime-green coral in Slaughter Bay – a 40-year paper trail
May 17, 2026
The lime-green coral in Slaughter Bay – a 40-year paper trail
May 17, 2026

Green Mountain – the name I give this coral in my database – is a coral I’ve photographed for years as I swim past. Then I found its backstory in the Norfolk Island National Parks archives: a rough map, reused paper, a note in the margin – ‘still thriving’. That’s how baselines begin.

May 17, 2026
What Norfolk Island’s reef tells us about environmental blind spots
April 5, 2026
What Norfolk Island’s reef tells us about environmental blind spots
April 5, 2026

The Kingston dredging proposal on Norfolk Island raises a bigger question than dredging alone: how well do standard environmental assessment tools capture the real significance of a remote and unusual reef system like Norfolk Island’s?

April 5, 2026
Hammer coral time!
March 30, 2026
Hammer coral time!
March 30, 2026

Hammer corals have unique tentacles that are large, fleshy, and tubular; these terminate in a ‘T’-shaped, hammer-head or anchor. Beneath all these softly waving tentacles is an extraordinary skeleton structure, which helps define them as a large polyp stony coral.

March 30, 2026
Norfolk Island’s fishes: drifters, residents and the ones still missing
March 24, 2026
Norfolk Island’s fishes: drifters, residents and the ones still missing
March 24, 2026

Norfolk Island’s fish fauna reflects both connection and isolation. Some species may arrive from elsewhere as drifting larvae, some populations appear to persist locally, and some fishes known from islands on either side of Norfolk have still not been recorded here. This post looks at what old survey work, regional checklists and genetic studies suggest about that more complicated picture.

March 24, 2026
18 Jun 2025 (20)_crop.jpg
March 7, 2026
Alveopora or flowerpot coral – how to tell the difference
March 7, 2026

They look alike at first glance, but Alveopora and flowerpot corals are not the same. The easiest way to tell them apart is to count the tentacles.

March 7, 2026

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