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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
    • Underwater
    • Reef Fish
    • Sharks
    • Eels
    • Corals
    • Sea Anemones
    • Nudibranchs, Sea Slugs and Flatworms
    • Octopuses
    • Sea Urchins and Sea Cucumbers
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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 blog is rated in the Top 20 Coral Reef Blogs in the world.

Spotted porcupinefish, Diodon hystrix

A case of mistaken identity?

July 6, 2021

There have been biting cold winds blowing directly from the east for most of the last week, moving around to the north in the last couple of days, and quite a bit of rain. This has made it rather brisk getting out of the water, but when in, the conditions have been sublime, particularly in the shelter of Emily Bay. Fantastic glass-like viz has made exploring the sandy shallows a lot of fun.

On the Lone Pine side of the bay, since at least 17 June (when I first spotted it), a solo convict surgeonfish, Acanthurus triostegus, has been hanging with the group of blackspot sergeant, Abudefduf sordidus that inhabit the area. I do sometimes wonder what attracts a fish on its own like this to join up with a school of fishes that look slightly similar in shape, colour and markings. Safety? Mistaken identity? Who knows?

View fullsize Convict surgeonfish - Acanthurus triostegus
Convict surgeonfish - Acanthurus triostegus
View fullsize With blackspot sergeants - Abudefduf sordidus
With blackspot sergeants - Abudefduf sordidus
View fullsize Spotted porcupinefish - Diodon hystrix
Spotted porcupinefish - Diodon hystrix
View fullsize Spotted porcupinefish - Diodon hystrix
Spotted porcupinefish - Diodon hystrix

A small spotted porcupinefish, Diodon hystrix has been hovering out in the open in the same spot on the Salt House side of the bay since at least 28 June. These fish are generally nocturnal and solitary, and, although I have heard that they will be inquisitive and follow divers around like puppy dogs, here on Norfolk Island I find they are generally shy and tend to retreat when you get too near. When you do see them, they are often under rock ledges or in caves. Again, I’m not sure what is going on that this one should be so exposed and not mind remaining there while I photographed it. These fish are broadcast spawners, ‘meaning both sexes mate with many different partners during spawning events’.

I have one old scarred porcupinefish that I visit regularly in his cave. More often than not he comes to the front of his cave and peers out at me. I give him a thumbs up and head on my way.

Emily Bay has a wonderful raft, used by generations of adults, teens and children. It is synonymous with summer and fun. Each year it gets hauled from the water, cleaned, repaired and popped back, usually over the wintertime. Last year, the raft was in a very poor state of repair and, consequently, the Norfolk Island Regional Council’s maintenance workers rebuilt it from scratch.

Emily Bay’s iconic raft

This new version is a different design to the one we had before; now it sports flotation tanks beneath it. I understand these may have been put there to prevent children swimming under the raft and surfacing in the air pocket created by the rafters, but I am not entirely certain. Whatever, I am sure it seemed like a good idea.

Over the years, the raft has provided shelter beneath its timbers for a thriving fish nursery. Beneath the raft was an amazing sight, teeming with fry. I have photos of it before the rebuild and since. I wanted to give it a full year before I made any comment on the new design, but I can say now, for whatever reason, the fish simply have not used the raft that much since it was rebuilt. A couple of times I’ve seen small schools (as in tens of bubbas rather than hundreds), but within a day or two these have disappeared, hunted by the trevally and other fish. I witnessed trevally sweeping in a pack under the raft as they hunted for food. (Below is a video of how they operate, although this was not filmed at the raft.) The small fry were gone in no time. With the previous design they were able to quickly retreat up between the rafters, out of the way of the fast-moving trevally. Now, sadly, there is nowhere for them to go.

I should also add here, I am not criticising the new design or the thought behind the improvements. I am sure it was done with the best of intentions, but the consequence is that we have had very few babies growing up under the new raft. Something to consider.

View fullsize 22 April 2020
22 April 2020
View fullsize 22 April 2020
22 April 2020
View fullsize 3 May 2020
3 May 2020
View fullsize 16 April 2021
16 April 2021
View fullsize 5 May 2021
5 May 2021
View fullsize 16 May 2021
16 May 2021

Trevally, Pseudocaranx sp 'dentex', on the hunt for newly hatched fry, Emily Bay, Norfolk Island

← Winter in Norfolk Island's lagoonsMid-winter fabulousness →
Featured
Glimpses of recovery: what the reef could be if we let it
Jun 13, 2025
Glimpses of recovery: what the reef could be if we let it
Jun 13, 2025

Day 6 of this photo series from Norfolk Island coincides with the final day of the UN Ocean Conference in Nice. After a week of documenting decline, today’s post offers a different view – what reef recovery can look like when conditions improve. Drought in 2024 gave the reef a break, and the results were unmistakable: healthier corals, lower disease, and more fish. This is what’s possible if we act.

Jun 13, 2025
Warning signs: quiet and unnoticed collapse of two coral colonies
Jun 12, 2025
Warning signs: quiet and unnoticed collapse of two coral colonies
Jun 12, 2025

Day 5 of my blog series for the UN Ocean Conference: two long-lived coral colonies in Norfolk’s lagoon died quietly from disease. No drama – just slow collapse and overgrowth by algae. A reminder that not all reef losses are loud, but they are happening.

Jun 12, 2025
Warning signs:  what Norfolk Island’s reef is telling us
Jun 11, 2025
Warning signs: what Norfolk Island’s reef is telling us
Jun 11, 2025

Day 4 of a week-long photo series from Norfolk Island, shared during the UN Ocean Conference in Nice. Today’s post spotlights a Hydnophora pilosa colony where white syndrome appeared suddenly and spread quickly, taking out around a quarter of the coral. In the months that followed, algae quietly filled the gap – a subtle but telling shift from coral to algae that’s happening across the reef.

Jun 11, 2025
Warning signs: coral disease takes hold
Jun 10, 2025
Warning signs: coral disease takes hold
Jun 10, 2025

In Day 3 of this blog post series, published while leaders gather at the UN Ocean Conference in Nice, we see Norfolk Island’s coral reef lagoon quietly delivering a stark warning: recurrent land-based pollution, coral disease, and delayed decisions are dismantling this ecosystem in real time.

Jun 10, 2025
Warning signs: coral growth anomalies – the slow cancers of the reef
Jun 9, 2025
Warning signs: coral growth anomalies – the slow cancers of the reef
Jun 9, 2025

Day 2’s post coinciding with the UN Ocean Conference looks at coral growth anomalies – sometimes called coral ‘cancers’. These slow-moving diseases quietly weaken coral colonies, making them far more vulnerable to storm damage and algal takeover. On Norfolk Island’s reef, I’ve watched this exact process play out over several years. This is how chronic stress silently dismantles coral ecosystems.

Jun 9, 2025
Warning signs: shifting baselines on Norfolk Island’s reef
Jun 8, 2025
Warning signs: shifting baselines on Norfolk Island’s reef
Jun 8, 2025

Today is World Ocean Day — a timely moment to launch my week-long blog series on Norfolk Island’s reef. Each day this week, I’ll be sharing photo essays that document the slow but steady pressures reshaping this fragile reef. Today: how shifting baselines make us blind to what we’ve already lost.

Jun 8, 2025
The Governance–Government Vacuum: Norfolk Island’s Forgotten Ecology
Apr 29, 2025
The Governance–Government Vacuum: Norfolk Island’s Forgotten Ecology
Apr 29, 2025

A personal reflection on Norfolk Island’s coral reef environment, political denial, and what John Wyndham’s The Kraken Wakes can still teach us about slow-moving disasters — and why this election matters more than ever.

Apr 29, 2025
Cute as buttons – Astrea curta
Feb 20, 2025
Cute as buttons – Astrea curta
Feb 20, 2025

Astrea curta corals are ‘small, moderately plocoid [flattened], distinct, and almost circular’ . Normally grey-green in colour, you can see from the images here, ours are often beautiful rich gold, although they do vary. They have a neat growth habit and button-like corallites, which can grow in columns, spherically or flattened. Large colonies of these can form gorgeous undulating bumps.

Feb 20, 2025
From 'Watch' to 'Warning'
Jan 26, 2025
From 'Watch' to 'Warning'
Jan 26, 2025

Last week, the chance of coral bleaching in Norfolk Island’s inshore lagoons was raised from ‘Watch’ to ‘Warning’ and will more than likely rise to Alert levels one and two in coming weeks. So why do I worry about water quality all the time when bleaching seems inevitable these days and so the reef is probably doomed anyway? Read on to find out.

Jan 26, 2025
From little things – watching them grow
Jan 4, 2025
From little things – watching them grow
Jan 4, 2025

Small numbers of different fish species is not an unusual phenomenon on Norfolk Island’s reef, but it does demonstrate what a tiny, precious, coral reef ecosystem we have, when we can count individuals on one hand and watch each of them grow, like these little blackeye thicklips, a member of the wrasse family.

Jan 4, 2025

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