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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 - 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.

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
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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
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Mar 7, 2026
Alveopora or flowerpot coral – how to tell the difference
Mar 7, 2026

They look alike at first glance, but Alveopora and flowerpot corals are not the same. The easiest way to tell them apart is to count the tentacles.

Mar 7, 2026
Norfolk’s lagoonal reef – the 2025 report, in plain English
Feb 27, 2026
Norfolk’s lagoonal reef – the 2025 report, in plain English
Feb 27, 2026

We now have the 2025 Norfolk Island reef health report, so I’m taking the opportunity to translate it into plain English here. Sadly, it’s more of the same story in Emily and Slaughter Bays – a reef that can cope with some stress, but is being asked to cope with too much, too often.

Feb 27, 2026
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.

Feb 20, 2026
Reef real estate – a bubble-tip’s six-year stand-off
Jan 11, 2026
Reef real estate – a bubble-tip’s six-year stand-off
Jan 11, 2026

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

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