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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
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    • Eels
    • Everything Else
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    • Out On A Swim Index
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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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The methane-busting algae, Asparagopsis taxiformis, Norfolk Island

The red seaweed behind low-methane beef

June 28, 2026

A small red seaweed on Norfolk’s reef has become part of a much bigger story. Asparagopsis taxiformis can look like a delicate red feather duster or, at another stage of its life cycle, like a tiny cottony pom-pom. It is beautiful, easily overlooked, and now being used in the cattle industry to help reduce methane emissions. This post looks at the reef oddity behind the low-methane beef story – and why repeated local observation can be more useful than it first appears.

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In Algae Tags algae, Algae farms, Landline, Asparagopsis taxiformis, Norfolk Island
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An aatuti guarding his eggs, Norfolk Island

From coral scar to aatuti farm

June 20, 2026

Aatuti are bold little algae farmers, but how does one of their farms begin? Over the past year, I have been following several coral patches as small white scars became algal footholds, then larger defended patches. I still cannot say what caused the first wounds, but the photo sequences show something fascinating: on a reef where algae is already gaining ground, even tiny changes on the coral surface can become part of a much bigger story.

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In Fish Tags Fish behaviour, Fish, aatuti, Parma polylepsis, banded scalyfin, algae, Algae farms
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Halimeda with a bright green segment at/near dawn – chloroplasts concentrated in the new growth

Halimeda’s night shift – why this reef algae changes colour

February 20, 2026

Halimeda is a calcareous green reef alga that forms new segments overnight, shifts from white to bright green by dawn, then pales again as calcification begins. A quick look at one of the reef’s smartest algae.

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In Algae Tags algae, Calcium carbonate, coralline algae, Halimeda, carbon sink
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Healthy montipora coral, Norfolk Island

Warning signs: shifting baselines on Norfolk Island’s reef

June 8, 2025

Today is World Ocean Day — a timely moment to launch my week-long blog series on Norfolk Island’s reef. Each day this week, I’ll be sharing photo essays that document the slow but steady pressures reshaping this fragile reef. Today: how shifting baselines make us blind to what we’ve already lost.

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In Environmental degradation Tags White syndrome, algae, coral reef, coral disease, Coral, phase shift, shifting baseline syndrome, UNOceanConference, Marine Conservation, Reef Health
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Free weed!

December 22, 2023

I couldn’t resist posting these beautiful images of floating seaweed. Enjoy!

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In Biodiversity, Algae Tags seaweed, algae, Norfolk Island
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The marine algae Hydroclathrus clathratus, Norfolk Island

Sponge blob!

October 29, 2023

It’s common, wide spread around the globe, and yet I have only noticed it in recent weeks. It has been hiding in plain sight, yet this spongey algal blob, Hydroclathrus clathratus, is edible, and has been found to possess some remarkable medicinal properties. Read on to find out more!

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In Algae Tags algae, Hydroclathrus clathratus, Medicine, research, anti-viral, edible algae, seaweed
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Crustose coralline algae, Norfolk Island

Pretty in pink – the real coral reef builders

April 8, 2023

Animal, vegetable or mineral? What are crustose coralline algae? Are they important? What role do they play on our coral reefs?

There’s a lot to learn about coralline algae. For a humble lifeform, they really pack a punch.

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In Ecosystem Tags algae, coralline algae, crustose coralline algae, coral reef, corals, sea urchin, coral recruitment
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Healthy montipora coral, Norfolk Island

Portrait of a slow death

March 10, 2023

Today’s focus on Norfolk Island’s reef is a photo essay. This series of photographs taken over the course of a year demonstrates how disease affects a montipora coral bommie by gradually killing the coral and creating an environment that allows algae to gain a foothold and to eventually take over.

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In Environmental degradation Tags White syndrome, algae, coral reef, coral disease, Coral, phase shift, shifting baseline syndrome
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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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Stylocheilus striatus – commonly called the lined sea hare, blue ring sea hare or furry sea hare

Furry sea hares as eco-warriors

December 12, 2021

Stylocheilus striatus – commonly called the lined sea hare, blue ring sea hare or furry sea hare – have appeared in numbers at one end of the shallows of Emily Bay. These little sea hares are great to have around as they consume the toxic blue-green alga that fish and other herbivores don’t or can’t eat or tolerate.

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Tags sea hares, eco-warriors, ecosystem, algae, nutrients, pollution, water quality, Emily Bay
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Featured
When algae move in – the changing reef neighbourhood
November 1, 2026
When algae move in – the changing reef neighbourhood
November 1, 2026

Algae are a natural part of Norfolk Island's reef, changing with the underwater seasons. But sometimes their beautiful green growth conceals a rather sad story. In the fifth article of my six-part photographic series, I revisit familiar places to see how algae have changed over the years – and what might be hiding underneath.

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November 1, 2026
The slow disappearance – disease on the reef
October 30, 2026
The slow disappearance – disease on the reef
October 30, 2026

What happens after coral disease has run its course? In the fourth article of my six-part photographic series, I revisit colonies I've watched lose living tissue, sometimes alarmingly quickly. From a potentially century-old brain coral that lost most of its living tissue in less than 100 days to the algae-covered skeletons left years later, these photographs reveal the longer-term consequences of coral disease on Norfolk Island's reef.

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October 30, 2026
When storms rearrange the reef
October 28, 2026
When storms rearrange the reef
October 28, 2026

Sometimes the sea rearranges a reef in a matter of hours! In the third article of my six-part photographic series, I revisit corals broken, overturned or swept away by powerful swells and storm surges. Some disappeared altogether, while others found surprising ways to survive. Five photographic sequences reveal just how dramatically Norfolk Island's reef can change.

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October 28, 2026
When the reef fights back – coral growth and recovery
October 26, 2026
When the reef fights back – coral growth and recovery
October 26, 2026

Not every coral story ends badly! Among six years of underwater photographs are some wonderful examples of growth, survival and recovery. From corals that have grown spectacularly to others that have survived bleaching, breakage or even being turned upside down, this second article in my photographic series celebrates some of the reef's more encouraging stories.

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October 26, 2026
The neighbours – six years of watching the same reef
October 24, 2026
The neighbours – six years of watching the same reef
October 24, 2026

When I began photographing Norfolk Island's reef in 2020, I simply recorded whatever caught my eye. Six years later, those photographs have become a record of individual corals and their changing fortunes – growth, competition, survival and loss. This is the first of six articles looking back at what I've seen, and sometimes what I wish I hadn't.

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October 24, 2026
Pulling the rugosity from out of the reef
October 10, 2026
Pulling the rugosity from out of the reef
October 10, 2026

What do ‘rugosity’, structural complexity and channeling your inner fish have in common? Quite a lot, as it turns out. This week I’m looking at how all the lumps, bumps, branches, holes and ledges on a reef create habitat – with a brief detour into one of my long-standing tricks for navigating tertiary study: write down the jargon until it starts to make sense.

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October 10, 2026
How does a sea slug smell?
September 27, 2026
How does a sea slug smell?
September 27, 2026

It started with a close-up of a little Elysia and two rhinophores that looked like tiny rolled-up scrolls. Once I noticed them, I started going back through years of sea-slug photos and realised just how wildly different these sensory organs can be – ridged, rolled, curled, tubular and, in sea hares, distinctly rabbit-eared. So this week’s rabbit hole is all about how sea slugs ‘smell’ underwater, and why their noses come in so many different shapes.

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September 27, 2026
The Elite Fleet sails in
September 19, 2026
The Elite Fleet sails in
September 19, 2026

Nearly six years ago, my very first blog post was about the strange blue and violet creatures that live at the ocean’s surface – a group I christened Norfolk Island’s ‘Elite Fleet’. Since then I’ve seen plenty of bluebottles and the occasional violet sea snail, but never a by-the-wind sailor. Until this morning. Velella velella is not a true jellyfish, but a colonial hydrozoan with a transparent sail that lets the wind help carry it across the ocean. So what exactly is this extraordinary little creature, how does it ‘sail’, and what connects it to the rest of the fleet?

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September 19, 2026
In a nutshell – where I stand on the proposed Norfolk Island Marine Park
September 18, 2026
In a nutshell – where I stand on the proposed Norfolk Island Marine Park
September 18, 2026

I support the proposed expansion of Norfolk Marine Park and its renaming as Norfolk Island Marine Park. There is much to welcome – strong offshore protection, no mining, and recognition of the importance of sustainable local fishing. But I also have some reservations. Why does Cascade need to be removed from the Marine Park at all? How will more than 430,000 km² actually be monitored and enforced? How do we make sure Norfolk people have a genuine role in management? And, above all, how do we ensure that the enormous new park does not draw attention away from the small, stressed reef immediately beside us?

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September 18, 2026
No seagrass, but plenty of turtles
September 13, 2026
No seagrass, but plenty of turtles
September 13, 2026

Norfolk Island does not have seagrass, although one of our most conspicuous green algae is often mistaken for it. Feather and grape Caulerpa can both form striking patches across the lagoon. I take a closer look at what Caulerpa actually is, why it is so easily confused with seagrass, and where our green turtles fit into the story.

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September 13, 2026

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