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Norfolk Island's Reef

Discover a fragile paradise – Norfolk Island's beaches, lagoons and coral reef
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    • Kingston, Norfolk Island
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  • Out on a swim - blog
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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.

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Bluespine unicornfish, Naso unicornis. Note the two scalpels at the base of its tail. These fish have been found to live to at least 50 years old. Norfolk Island

How surgeonfishes got their name

June 14, 2026

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.

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In Fish, Fish species Tags surgeonfish, Bluespine unicornfish, convict surgeonfish, pencil surgeonfish, Fish, Norfolk Island, reef fish
2 Comments

Echidna nebulosa, snowflake moray, Norfolk Island

A smooth and slippery echidna

December 10, 2024

How did the snowflake moray get its proper (scientific) name Echidna nebulosa, and what does it have to do with Australia’s famous and iconic marsupial, the echidna? Read on to find out more …

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In Fish, Fish species Tags Moray, Eel, Fish, Taxonomy, Echidna
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Blue-barred parrotfish (Scarus ghobban), last seen in September 2021

Fish stocktake – the mysteries, the surprises and the wins

April 22, 2024

In my ‘Year in review for 2023 on Norfolk Island’s reef’, published in December 2023, I made a few observations about the apparent disappearance of some fish species from Norfolk Island’s lagoons. I thought I would revisit these, principally because since December there has been so much additional fish activity here, with some exciting population increases and a few new species turning up.

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In Biodiversity, Fish, Fish species Tags Fish behaviour, Fish, weather, rainfall, fish species, observations
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A territorial banded scalyfin, Parma polylepis (aatuti), Norfolk Island

Know your damsels – multispine damselfish versus banded scalyfins

February 7, 2024

The banded scalyfins and the multispine damselfish are arguably two of the most common species in Norfolk Island’s lagoons. People often confuse them, particularly the juveniles, so here are some photos to clarify which are which. Once the differences have been pointed out, you’ll never confuse them again.

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In Fish species Tags fish species, fish, damselfish, aatuti, Norfolk Island
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A small school of scissortail sergeants with one interloper, an Indo-Pacific sergeant, Norfolk Island

Same, same, but different – confusing fish identities

May 25, 2023

There are a few fish species in Norfolk Island’s bays that are easily mixed up. Here’s four commonly confused pairs, with a few pointers to help you identify them.

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In Fish species Tags Fish, fish species, coral reef
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My grandson

For the sake of our grandchildren

March 26, 2023

What will my grandson see when he is old enough to snorkel on Norfolk Island’s reef? Will there be anything left as I know it? Or will he think it is all great because of that hoary old phenomenon called ‘shifting baseline syndrome’? This record of all my photos and observations will give him some idea of what we had in our bays in the 2020s.

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In Environmental degradation, Fish species Tags Environment, Environmental protection, water quality, biodiversity, grandchildren, Norfolk Island, Emily Bay
4 Comments

Black Blenny, Enchelyurus ater found in Slaughter Bay, Norfolk Island

Black Blenny - a new record for Norfolk Island

March 25, 2023

This is a copy of the Australian Fishes journal post about new fish sightings on Norfolk Island: ‘This observation [of a black blenny] highlights the power of citizen scientists working with professional ichthyologists to achieve important outcomes,’ Mark McGrouther, Senior Fellow at the Australian Museum.

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In Fish species Tags black blenny, fish species, Fish, new species, Australasian Fishes project, Australian Museum
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One of the pair of ‘sometimes’ resident snubnose darts, Norfolk Island

A pair and a spare – snubnose darts on Norfolk Island's reef

March 23, 2023

Norfolk Island’s reef is small and intimate. We can count the numbers of some species of fish on one hand, and that is how I can watch the comings and goings with interest as I swim among them. I love the stories that play out and which I get to witness – these snubnose darts (Trachinotus blochii) are a case in point.

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In Fish species Tags Snubnose dart, fish, fish species, fish behaviour
3 Comments

Threadfin butterflyfish, Chaetodon auriga, Norfolk Island

Butterfly, flutterbyfish

March 17, 2023

Butterflyfish are flighty, brightly coloured and beautifully conspicuous on our coral reef in their bright yellows and oranges, white and black livery. On Norfolk Island we regularly see fourteen species, just a small portion of the more than 100 species, globally. Large numbers of butterflyfish are a good sign of a healthy reef.

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In Fish species Tags butterflyfish, Fish, fish species, biodiversity, coral reef
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Yellowstripe goatfish, Mulloidichthys flavolineatus

By the hair of a goatfish's chinny chin chin!

March 16, 2023

If you go for a snorkel on Norfolk Island’s reef, one family of fish that you are bound to see is members of the goatfish family. I have seen have six different species inside our lagoons. You can see them all here.

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In Fish species Tags goatfish, Fish, fish species
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Adult female elegant wrasse, Norfolk Island

Ageing elegantly – the elegant wrasse's lifecycle

March 15, 2023

It’s always fascinating to see how fish change in appearance as they mature. Today’s blog post features the elegant wrasse, Anampses elegans. But not only do they change how they look, they also change how they socialise and move about the reef.

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In Fish species Tags fish species, Fish, Elegant wrasse
2 Comments

A bluestreak cleaner wrasse (Labroides dimidiatus) cleaning a coral sea gregory (Stegastes gascoynei)

One small fish for one big job

March 13, 2023

Bluestreak cleaner wrasse, Labroides dimidiatus, are important critters on our coral reefs. These fish offer a swim-through full-body maintenance shop for other fish species – their clients – nibbling away dead skin and any nasty ectoparasites that might be living on their clients. There’s a lot to be learned about a reef from watching these busy little fish.

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In Fish species Tags Bluestreak cleaner wrasse, cleaning stations, Fish, reef fish, fish species, parasites, Fish behaviour
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A peacock damselfish – Pomacentrus pavo

The curious case of the peacock damselfish

March 7, 2023

Today I am featuring a fish called the peacock damselfish – Pomacentrus pavo. On our tiny reef, you can often count the fish of a particular species on one hand, and the peacock damselfish is a perfect example of this. Our last baby peacock damselfishes appeared in mid-February (2021), but this year juvenile fish for any of the species in our bays have been hard to find. Maybe they are later this year?

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In Fish species Tags Peacock damselfish, Fish behaviour, Fish, fish species
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Featured
Reflections of an accidental marine scientist
August 1, 2026
Reflections of an accidental marine scientist
August 1, 2026

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.

August 1, 2026
From ridge to reef: unpicking the Waterway and Wetland Strategy
July 24, 2026
From ridge to reef: unpicking the Waterway and Wetland Strategy
July 24, 2026

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 24, 2026
Reef reality in pictures
July 13, 2026
Reef reality in pictures
July 13, 2026

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

July 13, 2026
The red seaweed behind low-methane beef
June 28, 2026
The red seaweed behind low-methane beef
June 28, 2026

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 28, 2026
From coral scar to aatuti farm
June 20, 2026
From coral scar to aatuti farm
June 20, 2026

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 20, 2026
Norfolk’s water quality – when action is reported as outcome
June 15, 2026
Norfolk’s water quality – when action is reported as outcome
June 15, 2026

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 15, 2026
How surgeonfishes got their name
June 14, 2026
How surgeonfishes got their name
June 14, 2026

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.

June 14, 2026
A shrimp storm
May 28, 2026
A shrimp storm
May 28, 2026

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.

May 28, 2026
Kingston dredging: what happens when a reef does not fit the framework
May 28, 2026
Kingston dredging: what happens when a reef does not fit the framework
May 28, 2026

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 28, 2026
Kingston dredging: the project advances, the questions remain
May 24, 2026
Kingston dredging: the project advances, the questions remain
May 24, 2026

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 24, 2026

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