Winter snorkelling on our reef — 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.

This blog is rated in the Top 20 Coral Reef Blogs in the world.

This week there has been some amazing, settled winter weather, the kind that makes Norfolk Island just sparkle and sing. And underwater was no different. Low, low tides associated with a new moon and quite good visibility have meant that my swims have been a delight.

This week, I was fortunate enough to see the male snubnose dart, Trachinotus blochii, cruising with his two female companions off the Salt House with a school of mullet. I am hoping this bodes well for some bubba darts in the coming summer season!

Snubnose dart - Trachinotus blochii

Other highlights included the bluespine unicornfish, Naso unicornis, posing for me in the early morning light, as only these fish can, before charging at me in a game of ‘call my bluff’. These guys are such show ponies! You can read about how unicornfish are so important to the health of a reef in an earlier blog post.

I also came nose to nose with our old resident female southern eagle ray, Myliobatis tenuicaudatus, with her distinctive stumpy tail, along with a brand new juvenile that I haven’t seen before in the shallows of Emily Bay. I photographed a pair courting inside Emily Bay back in December 2020. I wonder if this juvenile is the result (photos below).

But the one sighting that excited me beyond anything else was a teeny tiny juvenile blacktip morwong, Cheilodactylus francisi, on the Lone Pine side of the bay. This little fish, barely 1.5 to 2 cm in length, seemed unconcerned as I hovered over it trying to get a decent photo. I have only seen one of this species of fish in the bay, an adult, that lives in a very defined area, so it was a real treat to see what I have to assume is one of its progeny.

Southern eagle ray - Myliobatis tenuicaudatus

The new juvenile southern eagle ray

This was taken in December 2020

Blacktip morwong - Cheilodactylus francisi

Atagema spongiosa

I found a new species (to me) of sea slug in the bay as well, which is always exciting (photo above right), Atagema spongiosa.

And each time I was out I saw both resident green sea turtles snoozing in the channel, a couple of times within just a few metres of each other. They seem happy to take life in the slow lane for the time being and don’t swim off when I pause to observe them.

Today the weather has turned, with plenty of rain and blustery winds – more like the weather you would normally associate with winter.

That’s a wrap.

Mar 7, 2026

Alveopora or flowerpot coral – how to tell the difference

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.

Feb 27, 2026

Norfolk’s lagoonal reef – the 2025 report, in plain English

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 20, 2026

Halimeda’s night shift – why this reef algae changes colour

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.

Jan 11, 2026

Reef real estate – a bubble-tip’s six-year stand-off

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.

Dec 28, 2025

A year in review – 2025 on Norfolk Island's reef

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 15, 2025

Herbicides, heritage, and an inshore reef: what happens when land management meets lagoon health

Herbicide use near Emily, Slaughter and Cemetery Bays raises questions about inshore reef health, heritage land management, and environmental protection on Norfolk Island.

Dec 8, 2025

Signs of bleaching – 8 December 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 3, 2025

Nature is my teacher

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.

Nov 30, 2025

Reef grief: what dredging has done to other reefs

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 20, 2025

To dredge or not to dredge? The Kingston Pier channel project

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.