September full moon on Norfolk Island

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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More changeable weather this week with poor visibility in the bays curtailing some of my observations, but the full moon last night brought us some beautiful, settled weather, right on cue, which meant I was able to get out into Slaughter Bay for the first time in ages.

What greeted me wasn’t too pretty either. There is one area of coral I have been watching since the marine researchers from the Sydney Institute of Marine Science were here in March and alerted me to the onset of white syndrome, or white band disease. I have kept an eye on it since then and watched as the colony has gradually died. This week it was virtually unrecognisable, covered by a thick growth of algae. You can see the progression of the disease, below. Heartbreaking.

4 May 2021

11 June 2021

20 September 2021

A sure sign that things are warming up in the water was the sighting of a couple of Lady Musgrave blennies, Cirripectes chelomatus, out and about for the first time in yonks. I have seen them over winter, but it has been incredibly fleeting as they dashed for cover. This week my regular guy was happy to sit and be photographed. No sign of the chestnut eyelash blennies, Cirripectes castaneus, yet, though.

From now on, I expect to see these cheeky guys more and more. They tend to sit up on a prominent piece of coral, flutter up and then dive quickly back down and hide. And they will start to change colour as the season progresses to a beautiful greeny yellow with their blue tails. The first two images are from today. The others are to show you what I expect them to look like very soon.

Lady Musgrave blenny - Cirripectes chelomatus 20.09.21

17 November 2020

2 February 2021

Another fun photograph was of (I think*) a redcap triplefin, Enneapterygius rufopileus. These guys are a master of disguise. Probably less than 1 cm in length, they can be really hard to spot. Blink and they’re gone. The other image is of (I think*) a Doug’s eviota, Eviota hoesei. Similar in size to the redcap triplefin, and looking like a diminutive jewel, he has a black spot near his tail.

Redcap triplefin - Enneapterygius rufopileus

Doug's eviota - Eviota hoesei

To round off the week out on a swim, I thought I’d post one of my favourite butterflyfish, the vagabond butterflyfish, Chaetodon vagabundus. This is one of a pair that were happily flitting around in Slaughter Bay yesterday.

Vagabond butterflyfish - Chaetodon vagabundus

When I first started observing and photographing, I had no idea that there were so many variations on yellow, black and white among the butterflyfish. If you hop over to my reef fish page and scroll down to the Butterflyfish heading you will see what I mean.

*I've tried to get a definitive ID on these tiny critters on iNaturalist.org, but so far I've been unsuccessful.

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.