Ageing colourfully. This guy! — Norfolk Island's Reef

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.

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Green moon wrasse, Norfolk Island, 17 July 2024

As is often the case while I’m out on my swim, last week this guy was circling me, right in my face, peering at me as he swam around and around. He’s the alpha male in the Emily Bay and channel area of Norfolk Island’s reef. The boss – a green moon wrasse, Thalassoma lutescens.

In the oblique afternoon light I could see he was looking a little scarred and care-worn. Like an old war horse with a few battle scars.

Which got me wondering. How long has he been swimming beside me? When did I first capture him on camera?

In a blog post back in September 2021, I remarked, ‘The green moon wrasse were very active and inquisitive this week. One, in particular, followed me for a good half an hour as I made my way around the reef off the Salt House.’

That ‘one’ was this guy.

I tend to take him for granted because he is always around, in my face, posing for photos. I apologise for anthropomorphising here, but he’s inquisitive, fearless, and oozes chutzpah. He’s like a pet puppy.

I was rather emotional after seeing him looking visibly older, but it spurred me on to see when he first appeared in my life. I pored over my green moon wrasse folder of photos (and there are quite a few in there), checking all the images out for matching markings on each side of their faces. I ended up with quite a few that are definitely him, and quite a few that are ‘maybe’s. Below are the definites.

The first definite photo is in November 2020, at which stage he was a young adult, probably having recently transitioned from female to male. By that November the blue band around his middle, only sported by terminal males, had intensified in colour.

Since then he’s gained a few dents and scars, probably had lots of babies, and generally lived the best life a green moon wrasse can live.

Here’s his story in photos.

(Cont’d below)

Left side

28 November 2020

4 September 2021

21 November 2022

5 December 2022

1 February 2023

8 March 2023

25 November 2023

2 July 2024

Right side

28 November 2020

7 May 2021

28 October 2021

26 November 2021

25 January 2023

14 May 2023

26 July 2023

2 July 2024

Green moon wrasse are said to live five to seven years in the wild, which means that our lovely old friend could well be classified as an elder. I am guessing that one day soonish he just won’t be there, but at least I can show my appreciation for his friendly, show-pony cheek with his own dedicated blog post.

You’ve gotta love him!

And if you want to see the different colours at different life stages for this species of fish, go to my fish page on this site, and scroll down to W for Wrasses.

August 25, 2026

When the map changes

A fish once thought to belong only to Norfolk turns up elsewhere; another appears here hundreds of kilometres beyond its known range. Cardinalfishes and a Sabre squirrelfish show how our maps of species distributions are revised.

August 24, 2026

Endemic, native, undescribed – what do these words actually mean?

A Norfolk chromis that turned out not to be Chromis fumea, a blenny found nowhere else, and a tiny goby that may not yet have a name. A look at what we mean by native, endemic, undescribed and newly described – and why scientific names sometimes change.

August 16, 2026

What’s grazing in the green stuff?

A proliferation of Bryopsis on the reef has brought some beautiful little underwater grazers with it. I follow the trail from sap-sucking sea slugs and egg masses to a bigger question – why is there so much Bryopsis around at the moment?

August 8, 2026

The clam beneath Emily Bay

I’ve seen the beautiful shells of Laciolina chloroleuca in Emily Bay for decades, but I’d never really stopped to wonder where the living animals were. It turns out they may be buried half a metre beneath the sand. A closer look at an easily overlooked clam, its extraordinary shell markings, and the hidden life beneath our lagoon.

August 1, 2026

Reflections of an accidental marine scientist

What I thought would be a steady plod towards retirement, with plenty of time spent nursing grandchildren, was abruptly upended exactly six years ago today. This is the story of how an environmental catastrophe changed the course of my life – and led me to reinvent myself. It is a reflection on how, and why, I became an accidental marine scientist.

July 24, 2026

From ridge to reef: unpicking the Waterway and Wetland Strategy

Norfolk Island’s draft Waterway and Wetland Strategy will guide work for the next ten years. I support its intent, but it needs to be clear, practical and measurable – joining the dots from ridge to reef so we know whether public money is improving water quality and helping the reef.

July 13, 2026

Reef reality in pictures

Let the pictures do the talking. This is the reality on Norfolk Island’s reef today, laid out in a two-minute video.

June 28, 2026

The red seaweed behind low-methane beef

A small red seaweed on Norfolk’s reef has become part of a much bigger story. Asparagopsis taxiformis can look like a delicate red feather duster or, at another stage of its life cycle, like a tiny cottony pom-pom. It is beautiful, easily overlooked, and now being used in the cattle industry to help reduce methane emissions. This post looks at the reef oddity behind the low-methane beef story – and why repeated local observation can be more useful than it first appears.

June 20, 2026

From coral scar to aatuti farm

Aatuti are bold little algae farmers, but how does one of their farms begin? Over the past year, I have been following several coral patches as small white scars became algal footholds, then larger defended patches. I still cannot say what caused the first wounds, but the photo sequences show something fascinating: on a reef where algae is already gaining ground, even tiny changes on the coral surface can become part of a much bigger story.

June 15, 2026

Norfolk’s water quality – when action is reported as outcome

A recent Australian Government media release presents investment, monitoring and catchment works as progress on Norfolk Island’s water quality. Some of that work is useful, and some of it was badly needed. But activity is not the same as proven improvement. This post looks at Kingston sewerage, wetlands, cattle, acid sulfate soils, groundwater and reef health, and asks whether Emily Bay and Slaughter Bay are actually being better protected.