One Tree Island 2022

One Tree Island is part of the Great Barrier Reef. With over 2,900 individual reefs and 900 islands stretching over 2,300 Kilometres, the Great Barrier Reef  is the world’s largest coral reef system. One Tree Island is one of only two ‘no-entry scientific zones’ on the Great Barrier Reef. Unauthorised boats entering this area receive heavy penalties.

There is no resort or private housing on One Tree Island only the research station which is run by the University of Sydney, and managed by Heinrich and Ruby (and their baby, Lukas).

Heading off for an Island adventure without Tim was a very strange feeling. The 5 hour drive from home to Gladstone was uneventful. I stayed overnight in Gladstone then took the 2 hour ferry ride to Heron Island the next day. It was lovely to spend the day at Heron Island Research Station (HIRS) and catch up with friends there. On the afternoon high tide Heinrich (skipper), a marine research team of seven and I loaded luggage, equipment and food onto his boat and headed to One Tree Island (another 2 hour boat trip from Heron Island).

Heron Island

It was so exciting to see this tiny island again, with its beautiful reef and lagoon, and to spend time again with Heinrich and Ruby and meet baby Lukas. Tim and I were here in December 2021. You can see our blog from that visit here. One Tree Island, Qld 2021

One Tree Island
One Tree Island lagoon

Volunteer Work

My work on this trip was to help out looking after baby Lukas while Ruby and Heinrich worked. Being such a happy and contented baby, my job was easy and lots of fun. It was a busy time on the island, with seven researchers, 30 university visitors then 22 undergraduates and staff coming and going over the three week period. There was not a lot of down time for Ruby or Heinrich (the only staff on the island)

Research Team

Visitors from Sydney University

Thirty Sydney University staff came and went over a 6 day period, arriving and leaving by helicopter. This had to be done at low tide on the coral rubble as there is nowhere else on the island to land.

Heinrich meeting helicopter

Student Group

The second week of my stay we farewelled the research team and welcomed an undergraduate student group. Their boat from Gladstone was so large they had to wait outside the lagoon until the tide was high enough for them to cross the reef. With the luxury of a gang plank loading/unloading was much easier than usual.

The island

One Tree Island is a coral cay, part of the Capricorn Bunker group of islands. There is no sand, or soil, just coral rubble.


This Reef Stonefish was in very shallow water. It is the deadliest fish in the sea, with highly effective venom which can be lethal to humans.


Such an amazing variety of rays in the lagoon, and they are very good at camouflage.

Bait balls

bait ball, or baitball, occurs when small fish swarm in a tightly packed spherical formation …. a last-ditch defensive measure adopted by small schooling fish when they are threatened by predators. Small schooling fish are eaten by many types of predators, and for this reason they are called bait fish. (Wikipedia).

Bait ball in One Tree Island lagoon
Black tipped reef shark in bait ball OTI

From a distance you can see the path of the sharks through the bait balls, often there were 3 or 4 sharks together.

I swam through many bait balls trying to get close up footage of sharks, but they are so skittish I never succeeded. It was a lot of fun trying.

Bait ball One Tree Island

I also tried tying the GoPro to a rope and throwing it into the bait ball from the shore. Captured this lovely Lemon Shark.

Lemon Shark in bait ball, One Tree Island lagoon.

Below is a compilation of various animals I filmed while snorkelling. Thank you Tim for putting it together.

In order of video. Cowtail Stingray, Green Sea Turtle, Whiptail Stingray, school of Mullet, Blue Spotted Lagoon Ray and 2 different Shovelnose Rays

One Tree Island Lagoon 2022


One Tree Island, like the other Islands of the Capricorn Cays National Park and Capricorn Bunker Group , is a significant seabird rookery. The two most prolific birds on One Tree Island are the White Capped Noddies and Bridled Terns.

Every tree was packed with White Capped Noddy nests with chicks or eggs (they are also known as Black Noddies).

During a particularly windy night, several chicks fell out of their nests. Some of the mothers started feeding them on the ground. Not sure how many survived.

Bridle Terns nest on the ground and Heinrich and Ruby made little houses for them to protect from the heat and predators.

Their chicks start out as little fluffy grey balls, then become speckled brown as they grow, finally changing to grey and white like their parents.

Bridled Tern feeding chick

Around the island

The showers had a major improvement since our last visit. They now have a light in them.

The view from the toilet is still entertaining with so many White Capped Noddy nests right outside.

Toilet view of black noddy nests

A strange cloud formation.


Farewell One Tree Island, such a privilege to stay in this magical place.


P.S. Tim met me in Gladstone to drive the 5 hours home with me. So glad he did as we drove headfirst into a crazy hail storm. The temperature went from 32oC to 18oC in less than 5 minutes. Visibility was less than a metre. Noise was so loud we had to shout at each other to be heard. Couldn’t pull over as there were roadworks with concrete barricades on both sides of the road. Terrified the windscreen would smash. Finally got to pull over on a side road until it passed. Sides of the road were heaped with white hail stones, looked like snow. With in half an hour it was gone and there were blue skies and sunshine again. Car is so pitted with hail damage it looks like bubble wrap, and the windscreen is chipped. The insurance company is setting up a ‘pop up garage’ just to fix all the hail damaged cars.