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.

This page shows the most recent blog posts. For the complete catalogue, visit the ‘Out on a swim index’ page.

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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?

November 3, 2026

Familiar faces – getting to know the reef’s residents

Six years of swimming the same little reef have introduced me to some unforgettable characters that I’ve followed over time. From familiar fish and anemones to turtles and a snail’s eggs, this final article in my photographic series explores what I’ve learned about the lives of individual animals simply by returning, watching and taking photographs.

November 1, 2026

When algae move in – the changing reef neighbourhood

Algae are a natural part of Norfolk Island's reef, changing with the underwater seasons. But sometimes their beautiful green growth conceals a rather sad story. In the fifth article of my six-part photographic series, I revisit familiar places to see how algae have changed over the years – and what might be hiding underneath.

October 30, 2026

The slow disappearance – disease on the reef

What happens after coral disease has run its course? In the fourth article of my six-part photographic series, I revisit colonies I've watched lose living tissue, sometimes alarmingly quickly. From a potentially century-old brain coral that lost most of its living tissue in less than 100 days to the algae-covered skeletons left years later, these photographs reveal the longer-term consequences of coral disease on Norfolk Island's reef.

October 28, 2026

When storms rearrange the reef

Sometimes the sea rearranges a reef in a matter of hours! In the third article of my six-part photographic series, I revisit corals broken, overturned or swept away by powerful swells and storm surges. Some disappeared altogether, while others found surprising ways to survive. Five photographic sequences reveal just how dramatically Norfolk Island's reef can change.

October 26, 2026

When the reef fights back – coral growth and recovery

Not every coral story ends badly! Among six years of underwater photographs are some wonderful examples of growth, survival and recovery. From corals that have grown spectacularly to others that have survived bleaching, breakage or even being turned upside down, this second article in my photographic series celebrates some of the reef's more encouraging stories.

October 24, 2026

The neighbours – six years of watching the same reef

When I began photographing Norfolk Island's reef in 2020, I simply recorded whatever caught my eye. Six years later, those photographs have become a record of individual corals and their changing fortunes – growth, competition, survival and loss. This is the first of six articles looking back at what I've seen, and sometimes what I wish I hadn't.

October 10, 2026

Pulling the rugosity from out of the reef

What do ‘rugosity’, structural complexity and channeling your inner fish have in common? Quite a lot, as it turns out. This week I’m looking at how all the lumps, bumps, branches, holes and ledges on a reef create habitat – with a brief detour into one of my long-standing tricks for navigating tertiary study: write down the jargon until it starts to make sense.

September 27, 2026

How does a sea slug smell?

It started with a close-up of a little Elysia and two rhinophores that looked like tiny rolled-up scrolls. Once I noticed them, I started going back through years of sea-slug photos and realised just how wildly different these sensory organs can be – ridged, rolled, curled, tubular and, in sea hares, distinctly rabbit-eared. So this week’s rabbit hole is all about how sea slugs ‘smell’ underwater, and why their noses come in so many different shapes.

September 19, 2026

The Elite Fleet sails in

Nearly six years ago, my very first blog post was about the strange blue and violet creatures that live at the ocean’s surface – a group I christened Norfolk Island’s ‘Elite Fleet’. Since then I’ve seen plenty of bluebottles and the occasional violet sea snail, but never a by-the-wind sailor. Until this morning. Velella velella is not a true jellyfish, but a colonial hydrozoan with a transparent sail that lets the wind help carry it across the ocean. So what exactly is this extraordinary little creature, how does it ‘sail’, and what connects it to the rest of the fleet?

September 18, 2026

In a nutshell – where I stand on the proposed Norfolk Island Marine Park

I support the proposed expansion of Norfolk Marine Park and its renaming as Norfolk Island Marine Park. There is much to welcome – strong offshore protection, no mining, and recognition of the importance of sustainable local fishing. But I also have some reservations. Why does Cascade need to be removed from the Marine Park at all? How will more than 430,000 km² actually be monitored and enforced? How do we make sure Norfolk people have a genuine role in management? And, above all, how do we ensure that the enormous new park does not draw attention away from the small, stressed reef immediately beside us?