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

September 6, 2026

Watching El Niño from Norfolk Island

El Niño is strengthening across the Pacific, but that does not tell us exactly what the coming months will bring to Norfolk Island. After a long wet spell, I am watching our rainfall and water supplies more closely again – and, underwater, keeping an eye on sea temperature, algae, coral recruits and the fish that turn up on the reef.

September 2, 2026

What the world’s reefs are telling Norfolk Island

Two major new coral reef reports carry a clear message for Norfolk Island: reefs can recover when pressures ease, but the time available for recovery is shrinking. Norfolk Islanders were raising concerns about water quality, runoff and the health of Emily and Slaughter Bays nearly forty years ago. Today we have much better science, a changing climate and a far clearer understanding of how closely the catchment and reef are connected. This article looks at what that means for water quality, long-term monitoring, dredging and how we manage Kingston from land to sea.

August 25, 2026

When the map changes

A fish once thought to belong only to Norfolk turns up elsewhere; another appears here hundreds of kilometres beyond its known range. Cardinalfishes and a Sabre squirrelfish show how our maps of species distributions are revised.

August 24, 2026

Endemic, native, undescribed – what do these words actually mean?

A Norfolk chromis that turned out not to be Chromis fumea, a blenny found nowhere else, and a tiny goby that may not yet have a name. A look at what we mean by native, endemic, undescribed and newly described – and why scientific names sometimes change.

August 16, 2026

What’s grazing in the green stuff?

A proliferation of Bryopsis on the reef has brought some beautiful little underwater grazers with it. I follow the trail from sap-sucking sea slugs and egg masses to a bigger question – why is there so much Bryopsis around at the moment?

August 8, 2026

The clam beneath Emily Bay

I’ve seen the beautiful shells of Laciolina chloroleuca in Emily Bay for decades, but I’d never really stopped to wonder where the living animals were. It turns out they may be buried half a metre beneath the sand. A closer look at an easily overlooked clam, its extraordinary shell markings, and the hidden life beneath our lagoon.

August 1, 2026

Reflections of an accidental marine scientist

What I thought would be a steady plod towards retirement, with plenty of time spent nursing grandchildren, was abruptly upended exactly six years ago today. This is the story of how an environmental catastrophe changed the course of my life – and led me to reinvent myself. It is a reflection on how, and why, I became an accidental marine scientist.

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.

July 13, 2026

Reef reality in pictures

Let the pictures do the talking. This is the reality on Norfolk Island’s reef today, laid out in a two-minute video.

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.