Old friends return — 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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This week in the Norfolk Island lagoons saw some old friends return and some new (to me) visitors that appeared in Emily Bay for the first time. I also paid a visit to the more exposed Cemetery Bay for the first time since wild winds and surf went through earlier this month and last month.

On 16 June, I came across two of our larger parrotfish species – the marbled parrotfish, Leptoscarus vaigiensis and the bluebarred parrotfish, Scarus ghobban – hanging out together just off the Salt House in Emily Bay. I’ve watched both of these individuals grow into adulthood. Having started out in the shallows of Emily Bay, the marbled parrotfish tends to prefer the outer areas of the reef, near to where a channel was previously blasted through the reef. The bluebarred parrotfish is more wide-ranging and less skittish, happy to let me watch as he feeds off the algae using his two fused front teeth. This feature is what differentiates parrotfish from their close relatives, the large wrasse, Labridae, family.

Marbled parrotfish - Leptoscarus vaigiensis

Bluebarred parrotfish - Scarus ghobban

Other welcome visitors included our regular pair of snubnosed darts, Trachinotus blochii. These two love to placidly graze in the shallows at the Lone Pine end of Emily Bay, but I have also seen them in the sandy shallows at Slaughter Bay. One of them has a distinctive nip out of his tail, so I can tell it is the same pair.

The following day I saw a solo convict surgeonfish, Acanthurus triostegus, for the first time in the Emily Bay lagoon. I’ve only ever seen these in Cemetery Bay before, and usually in small schools of the same species.

Snubnose dart - Trachinotus blochii

Convict surgeonfish - Acanthurus triostegus

I also found hiding in plain sight a rather weird looking coral, called Rhodactis bryoides. Once I’d seen one or two, then I saw a whole carpet of them. These were all on the reef immediately adjacent to the Salt House.

Finally, a brief word about Cemetery Bay. I ventured into the water there on Sunday for the first time in perhaps a couple of months. In the intervening time we’ve had those huge swells and surf I mentioned in my nature journal published on 8 June. At the far end, away from the cemetery, the beach has been scoured out, with rocks and sand dumped liberally up onto the grassed area above. In the lagoon it was unrecognisable, with drifts of sand filling the channels, and some smashed coral. Hopefully, over time, the sand will clear naturally. But for the moment it is quite a different scene below water!

Rhodactis bryoides

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.

June 28, 2026

The red seaweed behind low-methane beef

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.

June 20, 2026

From coral scar to aatuti farm

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.

June 15, 2026

Norfolk’s water quality – when action is reported as outcome

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 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.