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.

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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

June 14, 2026

How surgeonfishes got their name

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.

May 28, 2026

A shrimp storm

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.

Kingston dredging: what happens when a reef does not fit the framework

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 24, 2026

Kingston dredging: the project advances, the questions remain

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 17, 2026

The lime-green coral in Slaughter Bay – a 40-year paper trail

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.

April 5, 2026

What Norfolk Island’s reef tells us about environmental blind spots

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?

March 30, 2026

Hammer coral time!

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 24, 2026

Norfolk Island’s fishes: drifters, residents and the ones still missing

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 7, 2026

Alveopora or flowerpot coral – how to tell the difference

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.

February 27, 2026

Norfolk’s lagoonal reef – the 2025 report, in plain English

We now have the 2025 Norfolk Island reef health report, so I’m taking the opportunity to translate it into plain English here. Sadly, it’s more of the same story in Emily and Slaughter Bays – a reef that can cope with some stress, but is being asked to cope with too much, too often.