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Norfolk Island's Reef

Discover a fragile paradise – Norfolk Island's beaches, lagoons and coral reef
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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.

A peacock damselfish – Pomacentrus pavo

The curious case of the peacock damselfish

March 7, 2023

Day 7 – March focus on Norfolk Island’s reef

Juvenile peacock damselfish, Pomacentrus pavo, February 2021

Today in my March focus on the coral reef of Norfolk Island I am featuring a fish called the peacock damselfish – Pomacentrus pavo. They are a delicate little fish, a gorgeous neon blue with a pale lemon-tipped tail, which only grow to 8.5 or 9 cm. It can be distinguished from similar fish (such as the neon damsel) by the tiny dark ‘ear’ spot near its gill cover.

I’m rather curious about this guy’s life cycle. Our inshore reef – from Emily Bay to Slaughter Bay – is small, so it’s relatively easy to get to know what is in there. Often you can count the fish of a particular species on one hand, and the peacock damselfish is a perfect example of this.

Because I have been only looking at three individuals, it is interesting to notice how their colours change throughout the year (see the images below). Or maybe it is a trick of the light. Certainly, they seem to lighten up from October through to February.

For ages we had just one that I would see regularly hugging a large bommie in Emily, often on the shady side. I never saw any others of his kind, until one day I saw five babies near a small inshore rock, quite some distance from the original bommie. So clearly there must have been a few others around. That was in February 2021. These babies seemed to disperse across the Emily Bay and channel area that runs between the two bays. At first, I could find four of them, then one disappeared and we were left with just three. For the next 18 months or so I would stop by and observe these three individuals, all living quite distant from each other in a solo existence on their respective coral bommies.

I usually find them midway up the side of a reef wall, although when the coral spawns they get a little more daring and will swim happily around just above the reef, presumably snacking on the coral spawn like the other damsel species.

The curious thing is, that almost overnight at the very end of December, all three of these fish disappeared. Did a message get passed across the water column for them to meet up for breeding? And if so, how? Will they come back? Will there be more babies? I always seem to have so many questions and so few answers!

This year, juvenile fish for any of the species in our bays have been hard to find and I have no idea why. Maybe they are later this year? Maybe the influx of freshwater has driven them out beyond the confines of the lagoons. Our last baby peacock damselfishes appeared in mid-February (2021), so I confess that I had expected to see some by now. I’ll keep looking!

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In Fish species Tags Peacock damselfish, Fish behaviour, Fish, fish species
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Featured
Halimeda’s night shift – why this reef algae changes colour
Feb 20, 2026
Halimeda’s night shift – why this reef algae changes colour
Feb 20, 2026

Halimeda is a calcareous green reef alga that forms new segments overnight, shifts from white to bright green by dawn, then pales again as calcification begins. A quick look at one of the reef’s smartest algae.

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Reef space is finite, and nothing ‘shares’ it politely. This short photo essay follows one bubble-tip anemone on Norfolk Island’s lagoonal reef as it holds a crater surrounded by Montipora. The coral builds a rim; the anemone holds the centre. Six years apart, and the argument continues.

Jan 11, 2026
A year in review – 2025 on Norfolk Island's reef
Dec 28, 2025
A year in review – 2025 on Norfolk Island's reef
Dec 28, 2025

Norfolk Island’s reef in 2025 – a year in review. From NOAA bleaching alerts and the UN Ocean Conference ‘Warning Signs’ series to post-drought coral recovery and a wet winter revealed in long-term rainfall records, this post captures the wins, losses, and shifting baselines beneath the lagoon. Includes reef photos, highlights from Reef Relief, and standout stories from 2025 – from coral health and disease to boxfish biomimicry, sea urchins, nudibranchs, and heat-stress signals in anemones.

Dec 28, 2025
Herbicides, heritage, and an inshore reef: what happens when land management meets lagoon health
Dec 15, 2025
Herbicides, heritage, and an inshore reef: what happens when land management meets lagoon health
Dec 15, 2025

Herbicide use near Emily, Slaughter and Cemetery Bays raises questions about inshore reef health, heritage land management, and environmental protection on Norfolk Island.

Dec 15, 2025
Signs of bleaching – 8 December 2025
Dec 8, 2025
Signs of bleaching – 8 December 2025
Dec 8, 2025

I took these photographs this morning, Monday, 8 December 2025. A few warm days of settled weather, little cloud cover and low tides in the hottest part of the day have led to some early bleaching on our reef. Bleaching doesn’t always mean death for our corals, but it is concerning to have this so early in the summer season. Fingers crossed the conditions don’t last and the reef can recover.

Dec 8, 2025
Nature is my teacher
Dec 3, 2025
Nature is my teacher
Dec 3, 2025

This is a thank-you note. Five years after my first Out on a swim post – written with zero marine science quals and a head full of questions – I’m still in the water, now as a PhD candidate, because an extraordinary mix of locals, volunteers, researchers and public servants decided to share what they knew. This is the story of how nature – and a very patient community – became my teachers.

Dec 3, 2025
Reef grief: what dredging has done to other reefs
Nov 30, 2025
Reef grief: what dredging has done to other reefs
Nov 30, 2025

From Miami to Fiji, from Dubai to tiny village harbours on atolls, dredging near coral reefs has left a long trail of scars – even on ‘small’ projects. This follow-up to last week’s Kingston post walks through real examples of what happened elsewhere, and what that should make us think about before we dig up our own reef.

Nov 30, 2025
To dredge or not to dredge? The Kingston Pier channel project
Nov 20, 2025
To dredge or not to dredge? The Kingston Pier channel project
Nov 20, 2025

How much risk are we really taking with the planned dredging at Kingston Pier – and how much protection do our corals actually have on paper? This piece walks through what the federal approval does and doesn’t guarantee, explains why sediment and light matter so much to the reef, and asks the hard questions we need answered before we trade a deeper channel for a shallower future.

Nov 20, 2025
A coral reef out of balance
Nov 8, 2025
A coral reef out of balance
Nov 8, 2025

After the long dry spell, the lagoon was crystal clear and full of life. But with the return of the rains, something else has returned too – the brown, filamentous mats of Lyngbya. It’s not seaweed, it’s a cyanobacterium, and when it takes hold it smothers coral and rubble alike. The reef’s way of showing us that every drop of water, from tank to tide, is connected.

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Aglow among the spines
Oct 25, 2025
Aglow among the spines
Oct 25, 2025

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