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 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?

September 13, 2026

No seagrass, but plenty of turtles

Norfolk Island does not have seagrass, although one of our most conspicuous green algae is often mistaken for it. Feather and grape Caulerpa can both form striking patches across the lagoon. I take a closer look at what Caulerpa actually is, why it is so easily confused with seagrass, and where our green turtles fit into the story.

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.