Turtles and snake eels — 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.

This blog is rated in the Top 20 Coral Reef Blogs in the world.

We’ve had yet another week of south easterlies stirring up the bays making visibility poor for taking photographs. That doesn’t mean I haven’t enjoyed my swims, though. Emily Bay never fails to lift my spirits.

A really exciting observation for me this week was the spotfin squirrelfish, Neoniphon samara. I can count on one hand the number of times I’ve seen this guy (and I am pretty sure it is the same one) in the last couple of years. That is because they are nocturnal (a clue to this is their huge eyes). This fish is very shy and ducks under an Acropora coral shelf very fast when it sees me, so you have to point and shoot really quickly – with varying results! It lives under these coral shelves during the day and then emerges out to the seagrass beds and hard-bottomed habitats at night, when it feeds on shrimps, small crabs and fish. (Reference Fishbase and Bray, D.J. 2020, Neoniphon sammara in Fishes of Australia, both accessed 28 Sep 2021.)

I also observed several snake eels out and about this week: two convict eels, Leiuranus versicolor, and one banded snake eel, Leiuranus semicinctus. I have put three up here for you to see (two top images and bottom left). The markings, even in the same species, are quite different and change as they age. You can see more of these snake eels, as well as the varieties of moray eels, over on the eels page of this website. They are quite docile and are usually found in the sandy reaches of the bay – they can bury themselves in the sand as quick as a flash. We also find a spotted snake eel, called the ocellate snake eel, Myrichthys maculosus, in our bays from time to time. So you can see the difference, I’ve included an image of this one taken a few months ago (bottom right)..

Here’s some quick snake eel facts for you:

They are a fish, and not a snake (an eel is a type of fish).
They breathe underwater using gills (snakes have lungs).
They can live up to 20 years.
They are nocturnal animals, which is why it is always exciting to see one during the daytime.
They bury themselves in the sand to hide from predators.

Banded snake eel - Leiuranus semicinctus

Convict snake eel - Leiuranus versicolor

Ocellate snake eel - Myrichthys maculosus

We have two resident green sea turtles, Chelonia mydas, that seem to snooze quite a bit. When I see them both they are normally at least 5 m or 6 m apart, if not a lot further. Today, they were catnapping very close to each other.

Finally, tonight is my debut as an actor! I’ve been rehearsing really hard over some weeks for my 10-second cameo, playing myself as the person who photographed the mullet with a gold ring around its head! Hilarious! Paul Garnsey, an island resident, used the story as inspo for a short play called Goldfish. Wish me luck!

Until next week …

Green sea turtles - Chelonia mydas

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.

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.