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Norfolk Island's Reef

Discover a fragile paradise – Norfolk Island's beaches, lagoons and coral reef
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    • Algae
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    • Eels
    • Everything Else
    • Kingston, Norfolk Island
    • Nudibranchs, Sea Slugs and Flatworms
    • Octopuses
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    • Sharks
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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.

Lone Pine photographed from Emily Bay, showing the freshwater layer caused by innundation from the creek.

A Year in Review – 2022 on Norfolk Island's Reef

December 31, 2022

It’s always a good time to take stock of the year that was, so I’ve been thinking about what 2022 held for Norfolk Island’s reef. La Niña superimposed on La Niña has meant copious rainfall and a lagoon under stress: more algae, more coral disease, fewer fish. Here’s a quick run down of what has been happening on our reef during 2022.

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Be like Senator David Pocock - wear a rashie

Sunbeams and sunscreens

December 19, 2022

Did you know that sunscreen is highly toxic?

From 1 January 2021, Hawaii banned all sunscreens containing the reef-harming chemicals oxybenzone and octinoxate, and with good reason. This radical action was taken because unsafe sunscreens can, and have, caused ecological ruination to coral reefs.

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In Ecosystem Tags corals, coral reef, coral reproduction, fish, Fish reproduction, Sunscreens, reef-safe sunscreen, Norfolk Island
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Black-mouthed tun snail, Tonna melanostoma

The black-mouthed tun snail – diary of an egg mass

December 12, 2022

The black-mouthed tun shell’s egg mass is photographed almost daily over a period of six weeks, from the morning they are laid until becoming dislodged from their rock after a period of big swells and storm surges.

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Norfolk Island's forgotten reef needs help

December 4, 2022

It’s been widely reported since the 1960s, at least, that nutrient-laden water flowing out the channel into Emily Bay is having a detrimental effect on Norfolk Island’s reef – a reef where it is thought that as much as 30 per cent of the corals are as yet undescribed. Are we going to do something about it before the reef has gone? Because, quite seriously, we have no time left to lose.

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Doris in her rehab tank

#OperationDoris – update from Australian Marine Parks

November 13, 2022

The following update on Norfolk Island’s rescue turtle, Doris, was released by Australian Marine Parks on 7 November 2022. For more information on Doris follow the hashtag #operationdoris.

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Norfolk Island's Blenny Fest

October 31, 2022

At this time of year, as the mating season begins, the delightful little Lady Musgrave blennies, Cirripectes chelomatus, change colour from dark inky blue black with a few barely visible red spots to a showy and vibrant mustard yellow.

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Tags Norfolk Island, Emily Bay, Fish behaviour, Blenny, Lady Musgrave blenny, coral reef
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A flatworm, Pseudobiceros sp, dining on the tunicates

Sea squirts – friend or foe?

October 17, 2022

Emily Bay and Slaughter Bay have recently experienced a significant increase in the numbers of overgrowing tunicates. In this post I take a look at these critters – which, incredibly, are distant cousins to humans – and ask some questions about their presence and impact on our coral reef ecosystem.

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In Ecosystem Tags tunicates, sea squirts, coral reef, corals, SlaughterBay, Emily Bay, ecosystem, biofouling, flatworms, ocean, Norfolk Island
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Doris, a young green sea turtle, in a bad way

#OperationDoris – green sea turtle rescue

September 14, 2022

One of our Norfolk Island turtles was covered in an unsightly algal growth. Not just her shell but over her eyes and her flippers too. I could see she needed help, but we had no facilities to nurse a sick turtle; however, with a strong community behind us, and plenty of caring people, this is just what we did. This is how #operationdoris unfolded.

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Corals found in the lagoons of Norfolk Island

First records of coral spawning on Norfolk Island

July 17, 2022

There were three confirmed coral spawning events on Norfolk Island’s coral reef during the 2021–2022 season. The evidence for these has now been published in Galaxea, Journal of Coral Reef Studies. Written by Professor Andrew Baird, chief investigator at the ARC Centre of Excellence for Coral Reef Studies, I am very kindly cited as a co-author because of my observations of these events. Read here to find out more.

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Tags coral spawning, corals, coral reef, coral reproduction, Norfolk Island, spawning
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Surge wrasse – Thalassoma purpureum

No, it's not a parrotfish!

June 26, 2022

Wrasse and parrotfish often get confused, but they each have quite differen roles to play on our reefs. Parrotfish are vital to the health of coral reefs. They clean up the surface algae that live on and compete with the coral. Read more to find out how they differ.

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Tags parrotfish, wrasse, Emily Bay, SlaughterBay, Cemetery Bay, Norfolk Island
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Sea cucumber, class Holothuroidea

Heroes of the beach – sea cucumbers

March 30, 2022

The beautiful sand of Emily Bay, Norfolk Island, didn’t get there by accident. It is the direct result of the hard pooping work of generations of marine animals, including parrotfish and sea cucumbers. This post takes a closer look at sea cucumbers and their role in the coral reef’s ecosystem.

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Emily Bay: Paragoniastrea australensis, also known as the lesser star coral, is a species of stony corals in the family Merulinidae. It occurs in shallow water in the Indo-Pacific region. (Source Wikipedia)

The ancient massives!

March 20, 2022

We have some beauties when it comes to brain corals inside our lagoons. They are quite amazing, and a hugely important part of a healthy reef. Here’s the low down!

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Tags corals, coral reef, Norfolk Island, brain coral, Cnidaria
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The Norfolk chromis, or Chromis norfolkensis

Norfolk chromis, the kissing fish

March 6, 2022

Norfolk Island now has a new species of fish. What was once classified as Chromis fumea has been recognised as a separate species, Chromis norfolkensis.

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Tonna melanostoma

Citizen science in action on Norfolk Island

February 28, 2022

My photos of the Tonna melanostoma, a giant underwater mollusc, are the only ones of the live animal in the public domain. We are so fortunate to have these special and rare creatures living in our coral-reef lagoons; their existence here serves to highlight what a special habitat Norfolk Island’s reef really is. It is an ecosystem that must be preserved at all costs.

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Tags Tonna melanostoma, Royal Belgian Society for Conchology, molluscs, tun shell, Emily Bay, Gloria Maris, ecosystem, rare sea snail
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Island Sea Star - Astrostole multispina

Sea stars? Starfish? What’s the difference?

February 7, 2022

Marine scientists have been giving these underwater stars an image makeover. The starfish of our childhoods, for those of you who have a few beachside summers under your beach towel, is now more properly known as a sea star. They have seawater for blood, two stomachs, no brain, and tiny ‘eyes’ at the end of each arm!

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In Sea stars Tags starfish, sea stars, Norfolk Island, ocean, coral reef
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Remnant reef overgrown with algae, 31 January 2022, Emily Bay, Norfolk Island

Come on in. The water's fine ...

January 31, 2022

As Costa Georgiadis says, nature tells the truth, and we must only look at our reef on Norfolk Island to know its truth. We, as custodians, have not been caring enough for it and now that carelessness is coming home to roost.

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In Environmental degradation Tags corals, coral reef, environment, ecosystems, alagae, pollution, Norfolk Island, Coral disease, water quality
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The Great Big Coral Spawn Myth

January 18, 2022

The mass spawning coral myth, debunked: coral mass spawning has captured the imagination of the public, while some of the coverage in the media has cemented a number of myths surrounding the event. The most pervasive being that mass spawning only occurs on one night each year. Not true! Read more here.

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In Corals Tags Coral, coral spawning, coral reproduction, Norfolk Island, spawning, coral reef
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Old Gnarly the swal doodle, Emily Bay, Norfolk Island

Old Gnarly, the swal doodle

January 1, 2022

When I’m out on my swim, one guy I always stop by and say hello to is Old Gnarly, a spotted porcupinefish known here as a swal doodle. He knows when I arrive. The first thing you see are his big luminescent white lips as he floats to the door of his cave. We pause, study each other for a moment, then I give him the thumbs up before continuing my swim. It is a precious moment when you connect with a wild animal like this, and it makes my day.

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Tags porcupinefish, puffer fish, Emily Bay, swal doodle
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Pink coral spawn floating on the surface of Emily Bay, Norfolk Island, 28 December 2021

Coral spawning, Norfolk Island 2021

December 29, 2021

Out on a swim on the morning of 27 December 2021, the mood was palpably different. Call me fanciful, but I immediately noticed a frisson of excitement among the fish. Lots of activity and agitation. And all kinds of slightly unusual observations. The annual coral spawning here on Norfolk Island had begun.

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Tags coral spawning, coral reef, coral reproduction, Norfolk Island, corals
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Stylocheilus striatus – commonly called the lined sea hare, blue ring sea hare or furry sea hare

Furry sea hares as eco-warriors

December 12, 2021

Stylocheilus striatus – commonly called the lined sea hare, blue ring sea hare or furry sea hare – have appeared in numbers at one end of the shallows of Emily Bay. These little sea hares are great to have around as they consume the toxic blue-green alga that fish and other herbivores don’t or can’t eat or tolerate.

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Tags sea hares, eco-warriors, ecosystem, algae, nutrients, pollution, water quality, Emily Bay
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Featured
18 Jun 2025 (20)_crop.jpg
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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