A pair and a spare – snubnose darts on 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.

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DAY 23 – MARCH FOCUS ON NORFOLK ISLAND’S REEF

Norfolk Island’s reef is small and intimate. We can count the numbers of some species of fish on one hand, which is how I can watch the comings and goings with interest as I swim among them. I love the stories that play out and which I get to witness, and these snubnose darts (Trachinotus blochii) are a case in point.

There are a pair of them that always hang out together. I have images going back to March 2020 of the same individuals, and I can tell they are the same ones because one of them has a slight nick out of the top fork of its caudal fin. They are what I call a ‘sometimes’ visitor. They come. They go. But more often than not they seem to reappear in March and disappear in November.

I have no idea what sex they are, but I do know that in mid 2021 they were joined by a much larger snubnose dart, which I assumed was a male. He was an impressive specimen, much larger, with a streamlined body of mirrored metallic silver. He stayed with the pair for a month or so, although I can’t tell you if he was with them 24/7 or if he came and went as the mood took him.

The juvenile trevally, smaller than my little finger

By October 2021, the pair were once again on their own, happily hanging in their favourite spots, either at the Lone Pine end of Emily Bay, or in the shallows of Slaughter Bay (although occasionally you will see them swimming between these two places). This time they were joined by a tiny passenger, a juvenile (baby) trevally. I’ve put a ring around him in the photo because he is so hard to see otherwise. If you click on the photo, it will enlarge.

I like to take credit for that baby’s introduction to the pair. The baby trevally had attached himself to me, swimming beside and around me for more than half of my hour-long swim. I am sure anyone who was watching from the shore thought I was demented as I spun around trying to capture him on film, so closely was he glued to my side.

I probably represented food or protection of some kind, but even so, it was quite the privilege to connect with this busy, happy little thing as he darted in and out of my field of vision. At the end of my swim, I found the two resident snubnose darts close to the Lone Pine end of Emily Bay. My little companion transferred his affiliations in a quicksilvery flash!

Fast forward to last week, in March 2023, and there were the pair of besties back foraging in Slaughter again. And there with them was a third wheel. A juvenile (teenager) trevally.

A tiny trevally inside the circle, October 2021

A trevally with the two darts, March 2023

The much larger (male?) snubnose dart with the two smaller residents in August 2021

I wonder? What do you reckon?

He is quite a bit bigger than before, but could it be the same one, 18 months later? The three of them circled around me a few times as I took their photo and then swam off.

Maybe I am being fanciful. But I do hope it was the same little trevally, because it certainly makes a delightful story.

There’s a lovely postscript, too. A week ago I spotted a young snubnose dart on its own in Emily Bay. Is it the progeny of the tryst made back in mid-2021 when the larger dart gatecrashed our lagoon, seemingly to court our two ‘sometimes’ residents? Who knows.

Why are there always so many more questions than answers?

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.