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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.

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
Celebrating Biodiversity Month on Norfolk Island
Sep 7, 2025
Celebrating Biodiversity Month on Norfolk Island
Sep 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.

Sep 7, 2025
The fate of a coral colony when it succumbs to white syndrome – four years on
Aug 24, 2025
The fate of a coral colony when it succumbs to white syndrome – four years on
Aug 24, 2025

I’ve tracked one plating Acropora coral from 2021 to 2025. In just a few weeks, white syndrome wiped it out. Nearly four years years on, it’s still smothered in algae and sea squirts, with only the tiniest hint of new growth. It’s a stark reminder: without tackling the root cause, we’re just watching the same sad story repeat itself.

Aug 24, 2025
The Candy-Striped Cleaner Keeping the Reef Healthy
Aug 17, 2025
The Candy-Striped Cleaner Keeping the Reef Healthy
Aug 17, 2025

Candy-cane stripes, long white feelers, and a reef spa on offer – the banded coral shrimp waves its antennae to advertise cleaning services to passing fish.

Aug 17, 2025
Biomimicry: How a Boxfish Caught Mercedes Benz’s Eye
Aug 10, 2025
Biomimicry: How a Boxfish Caught Mercedes Benz’s Eye
Aug 10, 2025

Meet Mr Lemonhead – our lagoon’s teeny yellow boxfish with a big design legacy. He inspired a Mercedes Benz concept car, proving how nature is full of surprises. And he shares the lagoon with other critters whose tricks have also shaped real-world inventions.

Aug 10, 2025
Patchwork Corals: How Colonies Fuse to Form Living Mosaics
Aug 3, 2025
Patchwork Corals: How Colonies Fuse to Form Living Mosaics
Aug 3, 2025

Some corals wear more than one colour for a reason. When Paragoniastrea australensis colonies fuse early in life, they form living mosaics. A beautiful reminder of coral cooperation on Norfolk Island’s reef.

Aug 3, 2025
Reef relief
Jul 28, 2025
Reef relief
Jul 28, 2025

Today, 28 July, is World Nature Conservation Day. After the dry 2024, Norfolk Island’s reef is looking healthier – a brief reprieve as less water - laden with nutrients - flowed into the lagoon. These photos show what’s possible. It’s a reminder that recovery is within reach – though renewed runoff could quickly undo the gains.

Jul 28, 2025
Emily Bay's big 'brain' coral
Jul 20, 2025
Emily Bay's big 'brain' coral
Jul 20, 2025

In Emily Bay, Norfolk Island, a single coral bommie – Paragoniastrea australensis – has stood for decades as a micro-reef, harbouring diverse marine life and local memories. Once photographed in 1988 and still thriving today, it remains a keystone of reef biodiversity and a living link between past and present.

Jul 20, 2025
Biodiversity matters
Jul 14, 2025
Biodiversity matters
Jul 14, 2025

Over five and a half years of snorkelling Norfolk’s lagoon, we’ve documented 23 fish species not previously recorded in this area. Some are local ghosts, others climate migrants. These observations help us understand and protect what makes our reef so special.

Jul 14, 2025
Poop power
Jun 17, 2025
Poop power
Jun 17, 2025

Not all poop on a reef is bad poop. In fact some kinds of poop can be a reef’s most important invisible engine. Fish poop, bird poop – even poop that gets eaten again by other fish – all of it keeps the ecosystem ticking over in a way that’s nothing short of extraordinary.

Jun 17, 2025
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

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