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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.

Eclipse butterflyfish – Chaetodon bennetti, Norfolk Island

Celebrating Biodiversity Month on Norfolk Island

September 7, 2025

September is Biodiversity Month and today, 7 September, is National Threatened Species Day – a reminder to pause and celebrate the astonishing variety of life that surrounds us. Here on Norfolk Island’s reef and in the lagoon, biodiversity is not an abstract concept. It’s the surgeonfish grazing the algae, the butterflyfish darting between corals, and the quiet arrival of new residents that I’ve been lucky enough to record in recent years – from the striking eclipse butterflyfish to the cute, cryptic black blenny.

Biodiversity matters. It’s important to know what we have. I wrote about it in a blog post earlier this year called ‘Biodiversity Matters’. As Lawrence and Hawthorne (2006) put it:

Knowing biodiversity achieves two things: it makes us better managers because we can observe what is there and measure the impact of our activities on biodiversity; and it motivates more of us to be managers, in the widest sense, by inspiring and educating us about the natural world.

That feels especially true here. The more I’ve come to know the reef, the more motivated I am to help care for it.

Globally, the importance of biodiversity was reaffirmed when 196 countries, including Australia, signed on to the Kunming–Montreal Global Biodiversity Framework at COP15 in 2022. Australia committed to halting and reversing biodiversity loss by 2030 and to living in harmony with nature by 2050. Three of the framework’s targets feel especially close to home for Norfolk Island’s lagoon: reducing pollution, minimising climate impacts, and ensuring that knowledge is accessible so that action can follow.

And yet, biodiversity isn’t just about policy documents and targets – it’s about joy, curiosity, and humility. As Confucius said more than 2,000 years ago (paraphrased):

To know that we know what we know, and that we do not know what we do not know, this is true knowledge.

Every new fish I spot, every coral colony that surprises me with its resilience, is a reminder of how much there still is to learn. Norfolk Island’s reef is a living library – one we’re only just beginning to read.

In the last five years or so, we have been able to add a further 23 fish species to those known to frequent inside the lagoons, building on the 97 species that were recorded in Ivanovici’s 1989 census (1989). Although it isn’t just about fish. It’s about all the corals, the invertebrates, all those things that we do not know that we don’t know. Together they all make up a unique ecosystem, like no other. A ecosystem that is special and worthy of our protection.

Biodiversity matters. To all of us.

A close up of Lobophyllia recta sensu Veron

I write about this coral, here: ‘You may call this beauty Lobophyllia recta sensu Veron’


* Back in 1985, Malcolm Francis began a long-term study documenting the fish fauna of Lord Howe Island, Norfolk Island, and the Kermadecs – all linked by latitude and ocean currents. His 1993 checklist of coastal fishes recorded 235 species for Norfolk Island. It is important to recognise that Malcolm’s list includes fish seen outside the lagoon, in open water, as well as inside the inshore reef area. He’s continued updating that list ever since, thanks in part to sightings contributed by local snorkellers, divers, and scientists alike. You can view his most recent version of the checklist here: Checklist of the coastal fishes of Lord Howe, Norfolk and Kermadec Islands – April 2025 (Figshare)

References

Ivanovici, A. 1988. ‘Emily Bay and Slaughter Bay, Norfolk Island: Resources and options for management’. Report. Australian National Parks and Wildlife Service.

Lawrence, A. & Hawthorne, W. 2006. Plant Identification: Creating User-Friendly Field Guides for Biodiversity Management. Earthscan, London.


In Biodiversity Tags biodiversity, Fish, corals, Norfolk Island, Emily Bay, Slaughter Bay
← Honoured to be featuredThe fate of a coral colony when it succumbs to white syndrome – four years on →
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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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