Mid-winter fabulousness — 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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We’ve had the most fabulous mid-winter weather over the weekend here on Norfolk Island. With a full moon on 24 June, we experienced some wonderful low, low tides. Peak low tides always lag the full moon (and new moon) by a day or so. This time it left Emily Bay looking like someone had pulled out the plug!

But let’s get onto what has caught my eye over the last week. (By the way, you can click on any image and a larger version will pop up.)

We have a couple snubnose darts, Trachinotus blochii, who are regular visitors to Emily and Slaughter Bays. I saw them in Emily on 16 June. Then, on 22 June, I hopped in at Slaughter Bay and saw them again, but this time they were accompanied by the biggest daddy of them all. The water was a little murky, but I did manage to capture a couple of shots (in the slide show at the bottom of this page). I guess that bodes well for some bubba snubnoses then!

Genus Goniobranchus — Genus *Goniobranchus*

Another great find (and a new one for me) this week was a small nudibranch hiding out under a rock shelf in Emily. I popped an image of it up in iNaturalist (do check this website out if you are interested in citizen science and wildlife, generally) and someone IDd it for me as being from the genus Goniobranchus.

A rather pretty group of goatfish have been chilling in the shallows of Emily for a couple of months. We have a few different types of goatfish here, but I’d not seen these ones before. You can see the other goatfish species under that heading on the Reef Fish page of this site. I finally managed to get some decent images of these, too, and an ID. It turns out they are Francis' goatfish - Upeneus francisi. Common to all goatfish, these guys have barbels – a pair of whiskery ‘feelers’ (or a goatee, hence their name) – protruding from their chins. These are studded with taste buds and are used to probe the sand in order to detect their prey.

Francis' goatfish - Upeneus francisi

Australian goatfish - Upeneus australiae

Snubnose dart - Trachinotus blochii

Banded scalyfin versus a sea hare

Sea hare with his mate, the tiny elysia

The final noteworthy observations this week are of sea hares. They’ve been in hiding for a month or two, tucked under rocks in ones and twos. But this week there seemed to be more of them out and about; some were grazing, but I saw quite a few with their heads up as if sniffing or tasting the seawater (images in the slifeshow, above). I chanced upon one being attacked by an aatuti (commonly known as a banded scalyfin, Parma polylepis). The sea hare squirted ink repeatedly, which definitely confused the aatuti. This vivid purply-red dye is toxic and used to deter predators. And I think it worked! See the images in the slideshow, above.

Another sea hare, a white-speckled one, Aplysia argus, was hanging out with a teeny tiny blue-spotted elysia, Plakobranchidae, a miniature cousin. These two are the original ‘Odd Couple’! You can see these two in the slideshow (above). To give you some idea of the scale of things, I could fit the sea hare into the palm of my hand.

And to finish, I have a lovely image of another sea hare – an underwater Shrek – image below!

Isn’t nature grand?

White-speckled sea hare - Aplysia argus — White-speckled sea hare - *Aplysia argus*

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?

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.