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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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My school’s logo and motto, Christ me spede

Honoured to be featured

September 30, 2025

I left school in the UK nearly 50 years ago, so it was a pleasant surprise to be invited to share some images and take part in an interview for an article about my work, to be published in the annual glossy magazine the school now produces. Here is the end product.

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In Biodiversity, Ecosystem, Education
Comment

Eclipse butterflyfish – Chaetodon bennetti, Norfolk Island

Celebrating Biodiversity Month on Norfolk Island

September 7, 2025

September is Biodiversity Month – the perfect time to celebrate the astonishing variety of life on Norfolk Island’s reef. From new fish sightings to coral mosaics, every observation is a reminder of how much there is still to learn and protect.

Read more about why biodiversity matters, globally and right here in our lagoon.

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In Biodiversity Tags biodiversity, Fish, corals, Norfolk Island, Emily Bay, Slaughter Bay
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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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Free weed!

December 22, 2023

I couldn’t resist posting these beautiful images of floating seaweed. Enjoy!

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In Biodiversity, Algae Tags seaweed, algae, Norfolk Island
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A Norfolk Island endemic species, the Norfolk Island blenny, Parablennius serratolineatus

Atlas of Living Australia recognises iNaturalist observations for Norfolk Island

August 16, 2023

After about 18 months of asking, and with the help of some wonderful people from the data department of the Atlas of Living Australia and the Australian Museum, the Atlas of Living Australia website now recognises iNaturalist citizen science observations for Norfolk Island. Which is definitely something worth celebrating!

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In Biodiversity Tags Citizen science, iNaturalist, observations, Atlas of Living Australia, Australian Museum, biodiversity, endemic species, Environment, environmental protections, Environmental protection
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Norfolk Island blenny, Parablennius serratolineatus

Norfolk Island's endemics on record

March 14, 2023

It is fascinating to me that, in terms of biodiversity, there is still a slight feel of the frontier to Norfolk Island. So remote and isolated from any other land mass, it stands to reason that we have some different species that are found only here. On such is the Norfolk Island blenny.

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In Biodiversity Tags fish species, Fish, endemic, Norfolk Island, Norfolk Island blenny
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A common view of an aatuti as you swim into its territory!

Phase shifts and biodiversity

March 9, 2023

One species that is doing remarkably well on Norfolk Island’s reef as it inexorably transitions from coral-dominated to algal-dominated is the banded scalyfin, Parma polylepis, which is unsurprising as their main food source is algae. The downside is they harass and bully all the other species that come anywhere near their territory, to the detriment of our biodiversity. Find out more here.

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In Biodiversity Tags banded scalyfin, biodiversity, phase shift, coral reef, algae, water quality
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From front to back: raccoon butterflyfish; blackback butterflyfish; three-striped butterflyfish Back right: Threadfin butterflyfish

No coral? No butterflyfish!

March 4, 2023

Butterflyfish are ‘corallivores’, that is, they feed mainly on coral polyps and the energy-rich mucous that these produce. Corals also make a great place for butterflyfish to shelter in and under. Without healthy corals, then fish like these will become more and more scarce.

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In Biodiversity Tags Butterflyfish, corals, coral reef, fish, fish species, biodiversity
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Featured
What Norfolk Island’s reef tells us about environmental blind spots
Apr 5, 2026
What Norfolk Island’s reef tells us about environmental blind spots
Apr 5, 2026

The Kingston dredging proposal on Norfolk Island raises a bigger question than dredging alone: how well do standard environmental assessment tools capture the real significance of a remote and unusual reef system like Norfolk Island’s?

Apr 5, 2026
Hammer coral time!
Mar 30, 2026
Hammer coral time!
Mar 30, 2026

Hammer corals have unique tentacles that are large, fleshy, and tubular; these terminate in a ‘T’-shaped, hammer-head or anchor. Beneath all these softly waving tentacles is an extraordinary skeleton structure, which helps define them as a large polyp stony coral.

Mar 30, 2026
Norfolk Island’s fishes: drifters, residents and the ones still missing
Mar 24, 2026
Norfolk Island’s fishes: drifters, residents and the ones still missing
Mar 24, 2026

Norfolk Island’s fish fauna reflects both connection and isolation. Some species may arrive from elsewhere as drifting larvae, some populations appear to persist locally, and some fishes known from islands on either side of Norfolk have still not been recorded here. This post looks at what old survey work, regional checklists and genetic studies suggest about that more complicated picture.

Mar 24, 2026
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

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