Jockeying for space on the reef — Norfolk Island's Reef

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.

I won’t lie, it has been a wipe-out in the bays this week. I sound repetitive, I know, but this year it has been like that! We’ve had massive swells once more, so even though I always carry my camera there was nothing to see let alone photograph!

Green sea turtle, Chelonia mydas, snoozing — Green sea turtle, *Chelonia mydas,* snoozing

Bluespotted cornetfish, Fistularia commersonii, with a school of yellowstripe goatfish — Bluespotted cornetfish, *Fistularia commersonii*, with a school of yellowstripe goatfish

Having said that, early this morning we had a reprieve with the most fabulous sparkling calm seas, a low tide and sunshine. The trifecta as far as I am concerned! It is possibly only short-lived, though, because storms are forecast for tomorrow.

Anyway, I more than made up for it this morning, with everyone out and about enjoying the spring sunshine. Apart from the turtle. She was asleep! I particularly enjoyed the bluespotted cornetfish, Fistularia commersonii, nonchalantly hanging with a school of yellowstripe goatfish, Mulloidichthys flavolineatus, like I couldn’t see it! Move on! Nothing to see here!

Normally skittish and shy, the three-striped butterflyfish, Chaetodon tricinctus, were having fun, too, with one getting a spring clean from a juvenile moon wrasse, Thalassoma lunare. I’ve seen this behaviour – when these juvenile moon wrasses perform the function of a cleaner wrasse – quite often. I have no idea if this is ‘normal’, but I do know a researcher who came here said he’d never seen this happening anywhere else before that he’d seen. I couldn’t get a decent photograph, so you’ll have to take my word for it (right-hand image below).

Three-striped butterflyfish - Chaetodon tricinctus

With a juv. moon wrasse (behind)

This blusepine unicornfish, Naso unicornis, was showing me his best side today as well!

Bluespine unicornfish - Naso unicornis

Finally, this week I wanted to show you some images of corals jockeying for space on the reef. The main reason they compete is for the rights to light. It is a war out there! I just love the juxtaposition of the different colours, even in the same species of coral.

Astrea curta

Paragoniastrea australensis

Lord Coral - Micromussa lordhowensis

Paragoniastrea australensis

September 13, 2026

No seagrass, but plenty of turtles

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.

September 6, 2026

Watching El Niño from Norfolk Island

El Niño is strengthening across the Pacific, but that does not tell us exactly what the coming months will bring to Norfolk Island. After a long wet spell, I am watching our rainfall and water supplies more closely again – and, underwater, keeping an eye on sea temperature, algae, coral recruits and the fish that turn up on the reef.

September 2, 2026

What the world’s reefs are telling Norfolk Island

Two major new coral reef reports carry a clear message for Norfolk Island: reefs can recover when pressures ease, but the time available for recovery is shrinking. Norfolk Islanders were raising concerns about water quality, runoff and the health of Emily and Slaughter Bays nearly forty years ago. Today we have much better science, a changing climate and a far clearer understanding of how closely the catchment and reef are connected. This article looks at what that means for water quality, long-term monitoring, dredging and how we manage Kingston from land to sea.

August 25, 2026

When the map changes

A fish once thought to belong only to Norfolk turns up elsewhere; another appears here hundreds of kilometres beyond its known range. Cardinalfishes and a Sabre squirrelfish show how our maps of species distributions are revised.

August 24, 2026

Endemic, native, undescribed – what do these words actually mean?

A Norfolk chromis that turned out not to be Chromis fumea, a blenny found nowhere else, and a tiny goby that may not yet have a name. A look at what we mean by native, endemic, undescribed and newly described – and why scientific names sometimes change.

August 16, 2026

What’s grazing in the green stuff?

A proliferation of Bryopsis on the reef has brought some beautiful little underwater grazers with it. I follow the trail from sap-sucking sea slugs and egg masses to a bigger question – why is there so much Bryopsis around at the moment?

August 8, 2026

The clam beneath Emily Bay

I’ve seen the beautiful shells of Laciolina chloroleuca in Emily Bay for decades, but I’d never really stopped to wonder where the living animals were. It turns out they may be buried half a metre beneath the sand. A closer look at an easily overlooked clam, its extraordinary shell markings, and the hidden life beneath our lagoon.

August 1, 2026

Reflections of an accidental marine scientist

What I thought would be a steady plod towards retirement, with plenty of time spent nursing grandchildren, was abruptly upended exactly six years ago today. This is the story of how an environmental catastrophe changed the course of my life – and led me to reinvent myself. It is a reflection on how, and why, I became an accidental marine scientist.

July 24, 2026

From ridge to reef: unpicking the Waterway and Wetland Strategy

Norfolk Island’s draft Waterway and Wetland Strategy will guide work for the next ten years. I support its intent, but it needs to be clear, practical and measurable – joining the dots from ridge to reef so we know whether public money is improving water quality and helping the reef.

July 13, 2026

Reef reality in pictures

Let the pictures do the talking. This is the reality on Norfolk Island’s reef today, laid out in a two-minute video.