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Norfolk Island's Reef

Discover a fragile paradise – Norfolk Island's beaches, lagoons and coral reef
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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.

The Emily Bay’s massive ‘brain’ coral, Paragoniastrea australensis, photographed on 6 July 2024

While you were sleeping ...

July 10, 2024

This post is a quick pictorial essay of one of our most recognisable coral bommies. This massive and incredibly slow-growing Paragoniastrea australensis sits off the Salt House inside Emily Bay on Norfolk Island. I have been told that it is a lot smaller than it used to be after sections tumbled off when storms came through. It’s still impressive, though, with many fish congregating around and within its folds. Sea anemones nestle in crevices, moray eels can sometimes be found poking out of holes, and banded scalyfins create their gardens on its sides. For some species, like the little peacock damselfish, Pomacentrus pavo, this coral is their world.

Most of the time, during daylight hours anyway, the unique maze across its face is a clear, crisply defined series of ridges. While all looks reasonably calm during the day, at night, while you are sleeping, the surface of the coral colony seethes with millions of tiny tentacles busily reaching out to find food, while others aggressively ward off opportunistic interlopers.

If you swim past just before dawn, as I did today, they will still be out, and you might notice that the surface of the colony has taken on a soft, fuzzy appearance. They also reach out with even longer ‘sweeper’ tentacles to ward off other corals that may want to invade, or grow, into their territory.

Below, you can see the coral during the day and in the pre-dawn. Click on each image to see a larger version.

I’ve posted about this species of coral before, so if you want to find out more, go here, War of the coral worlds! and, here, One hundred year-old coral gone in less that one hundred days.

View fullsize At night the tentacles come out
At night the tentacles come out
View fullsize They give the coral a velvety appearance
They give the coral a velvety appearance
View fullsize Longer sweeper tentacles also appear
Longer sweeper tentacles also appear
View fullsize Aggressively asserting their territory
Aggressively asserting their territory
View fullsize During the day the tentacles are retracted
During the day the tentacles are retracted
View fullsize A surge wrasse, Thalassoma purpureum
A surge wrasse, Thalassoma purpureum

The peacock damselfish, Pomacentrus pavo, that calls this bommie home

In Corals Tags corals, coral reef, bommie, Emily Bay, Norfolk Island
← Ageing colourfully. This guy!Gender transitioning in the birdnose wrasse →
Featured
Celebrating Biodiversity Month on Norfolk Island
Sep 7, 2025
Celebrating Biodiversity Month on Norfolk Island
Sep 7, 2025

September is Biodiversity Month – the perfect time to celebrate the astonishing variety of life on Norfolk Island’s reef. From new fish sightings to coral mosaics, every observation is a reminder of how much there is still to learn and protect.

Read more about why biodiversity matters, globally and right here in our lagoon.

Sep 7, 2025
The fate of a coral colony when it succumbs to white syndrome – four years on
Aug 24, 2025
The fate of a coral colony when it succumbs to white syndrome – four years on
Aug 24, 2025

I’ve tracked one plating Acropora coral from 2021 to 2025. In just a few weeks, white syndrome wiped it out. Nearly four years years on, it’s still smothered in algae and sea squirts, with only the tiniest hint of new growth. It’s a stark reminder: without tackling the root cause, we’re just watching the same sad story repeat itself.

Aug 24, 2025
The Candy-Striped Cleaner Keeping the Reef Healthy
Aug 17, 2025
The Candy-Striped Cleaner Keeping the Reef Healthy
Aug 17, 2025

Candy-cane stripes, long white feelers, and a reef spa on offer – the banded coral shrimp waves its antennae to advertise cleaning services to passing fish.

Aug 17, 2025
Biomimicry: How a Boxfish Caught Mercedes Benz’s Eye
Aug 10, 2025
Biomimicry: How a Boxfish Caught Mercedes Benz’s Eye
Aug 10, 2025

Meet Mr Lemonhead – our lagoon’s teeny yellow boxfish with a big design legacy. He inspired a Mercedes Benz concept car, proving how nature is full of surprises. And he shares the lagoon with other critters whose tricks have also shaped real-world inventions.

Aug 10, 2025
Patchwork Corals: How Colonies Fuse to Form Living Mosaics
Aug 3, 2025
Patchwork Corals: How Colonies Fuse to Form Living Mosaics
Aug 3, 2025

Some corals wear more than one colour for a reason. When Paragoniastrea australensis colonies fuse early in life, they form living mosaics. A beautiful reminder of coral cooperation on Norfolk Island’s reef.

Aug 3, 2025
Reef relief
Jul 28, 2025
Reef relief
Jul 28, 2025

Today, 28 July, is World Nature Conservation Day. After the dry 2024, Norfolk Island’s reef is looking healthier – a brief reprieve as less water - laden with nutrients - flowed into the lagoon. These photos show what’s possible. It’s a reminder that recovery is within reach – though renewed runoff could quickly undo the gains.

Jul 28, 2025
Emily Bay's big 'brain' coral
Jul 20, 2025
Emily Bay's big 'brain' coral
Jul 20, 2025

In Emily Bay, Norfolk Island, a single coral bommie – Paragoniastrea australensis – has stood for decades as a micro-reef, harbouring diverse marine life and local memories. Once photographed in 1988 and still thriving today, it remains a keystone of reef biodiversity and a living link between past and present.

Jul 20, 2025
Biodiversity matters
Jul 14, 2025
Biodiversity matters
Jul 14, 2025

Over five and a half years of snorkelling Norfolk’s lagoon, we’ve documented 23 fish species not previously recorded in this area. Some are local ghosts, others climate migrants. These observations help us understand and protect what makes our reef so special.

Jul 14, 2025
Poop power
Jun 17, 2025
Poop power
Jun 17, 2025

Not all poop on a reef is bad poop. In fact some kinds of poop can be a reef’s most important invisible engine. Fish poop, bird poop – even poop that gets eaten again by other fish – all of it keeps the ecosystem ticking over in a way that’s nothing short of extraordinary.

Jun 17, 2025
Glimpses of recovery: what the reef could be if we let it
Jun 13, 2025
Glimpses of recovery: what the reef could be if we let it
Jun 13, 2025

Day 6 of this photo series from Norfolk Island coincides with the final day of the UN Ocean Conference in Nice. After a week of documenting decline, today’s post offers a different view – what reef recovery can look like when conditions improve. Drought in 2024 gave the reef a break, and the results were unmistakable: healthier corals, lower disease, and more fish. This is what’s possible if we act.

Jun 13, 2025

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