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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.

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Male birdnose wrasse, Gomphosus varius, Norfolk Island

Gender transitioning in the birdnose wrasse

July 7, 2024

The bird or birdnose wrasse, Gomphosus varius, is a weird looking fish with a long snout that it uses to probe down into the coral branches to seek out crustaceans. They particularly like the cauliflower corals for this. They move around quickly, and can become a bit agressive and eat other small fish.

But the best part about the birdnose wrasse, though, is how it changes its appearance from a juvenile, through to a female and then finally a male (known as sexual metamorphosis, or sequential hermaphroditism). All birdnose wrasse are born female but will change to males if the conditions are right – for example when they are socially dominant or there isn’t another male around.

Each stage is radically different, from the stripey lime green juvy to the black and white female with her red snout, to the green male. The transition phase can be seen in the sequence of photos, below, where it shows some of the male colouring appearing while still having some of the female. This transition stage can last up to about three weeks.

Like all wrasse, it has well-developed and colourful pectoral fins, like wings, which it uses for swimming (rather than like other fish that use their tails). I’ve included an image of these beautiful pecs and one showing how it uses that distinctive snout, below.

View fullsize Juvenile
Juvenile
View fullsize Juvenile
Juvenile
View fullsize Female
Female
View fullsize Transition stage
Transition stage
View fullsize Transition stage
Transition stage
View fullsize Male
Male

A male birdnose wrasse using its beak to reach between the branches of coral for food

Showing off his pectoral fins

In Fish Tags Fish, Fish behaviour, fish species, wrasse, bird wrasse
← While you were sleeping ... One hundred year-old coral gone in less than one hundred days →
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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