The Problem
As global oceans continue to warm, many marine species are on the move. While this shift often rings alarm bells, it has led to an unexpected story unfolding beneath the waves of Sydney’s temperate coastline: coral.
That’s right — not just seaweed, sponges, or rocky reefs — but living, building, branching coral.
Over the last few years, Pocillopora aliciae, a branching tropical coral species, has been quietly establishing itself on Sydney’s rocky reefs. From Cabbage Tree Bay to North Head, it’s not only surviving — it’s building habitat, attracting tropical fish, and altering local marine ecosystems.
What we don’t know is how or why.
Why is this coral expanding so far south? How is it thriving in cooler, more nutrient-rich waters that usually stress or bleach tropical corals? And what does this mean for local biodiversity, restoration, and reef futures?
Without a clear picture of their distribution, health, and physiological resilience, we risk missing critical signals of change — or opportunity — in our coastal marine environment.
The Solution
Through the Sydney Coral Project, we’re launching the first comprehensive mapping of coral distribution in Sydney, from headlands to harbours, to establish where corals are thriving — and where they aren’t. This presence–absence data will provide a vital baseline for detecting future change, guiding conservation strategies, and supporting local reef restoration.
But our work goes deeper than maps.
Through innovative field and laboratory experiments, we’re investigating how Pocillopora aliciae has adapted to survive at the poleward edge of its range — in colder, more variable waters, with different nutrient and light conditions than its subtropical distribution. And this species doesn’t just appear to be coping, it’s thriving.
We’re studying:
• Physical and metabolic adaptations to temperature extremes
• Symbiosis dynamics between corals and their microalgal partners
• Nutritional ecology shifts in low-light, temperate habitats
• Reproductive strategies in a low-abundance ecosystem
This physiological insight doesn’t just improve our understanding of marine ecology in NSW — it could reveal resilience mechanisms relevant to vulnerable tropical reefs, including the Great Barrier Reef.
The Science
Supported by ZIMMERMANN, this initiative brings together cutting-edge marine research and community engagement. Co-designed by researchers at SIMS, UTS, USyd, and the Gamay Rangers, this project brings together expertise in marine biology, coral physiology, genetics, and environmental change.
Our research methods include:
• Underwater surveys to track coral presence and absence across Sydney
• Molecular genetics to determine population connectivity and diversity
• Metabolic and lipid profiling to assess temperature and light adaptation
• Symbiosis and bleaching experiments in controlled lab conditions
Our early results show that P. aliciae in Sydney is genetically diverse (not a single clone), adjusts its fat content for low-light living, and modifies its cell membranes to handle seasonal temperature swings — all signs of a robust, self-sustaining population.
We have also tested what this coral does when it encounters other resident corals – Plesiastrea versipora. We found that under current conditions, the Plesiastrea will outcompete Pocillopora, but if temperatures continue to get warmer more consistently, P. versipora will not survive. This is another important reason to better understand our current coral status across NSW, should the need for managements strategies arise.
Citizen Science
This is where you come in.
We’re inviting local divers, snorkellers, fishers, and ocean enthusiasts to help us map coral sightings around Sydney. You don’t need a science degree — just a pair of fins and a curious eye.
Seen this coral?
Look for a dark brown-green coral with chunky, rounded branches. It’s often found on rocky reefs exposed to swell — places like Manly, North Head, and Fairlight.
• Take a photo
• Record the location (and depth if known)
• Note the date
• Log your observations at SydneyCoralProject.com
And if you didn’t see any coral, let us know. Absence data is just as valuable in helping us understand habitat limits and ecosystem change. Your contributions will be used directly in scientific analyses, ecological models, and outreach materials that help shape Sydney’s marine future.
The Future
This project is just the beginning of a longer story — one that could change how we think about corals in a warming world.
With your help, we aim to:
• Create the first open-access coral distribution map for Sydney corals
• Monitor seasonal and long-term changes in coral health
• Integrate coral physiology into climate adaptation strategies
• Inform marine spatial planning, biodiversity zoning, and restoration priorities
• Contribute insights to national and global coral conservation research
By combining citizen observations, cutting-edge science, and community engagement, the Sydney Coral Project offers a new way to understand — and protect — our changing ocean.
Funding
This research is made possible through support from the Zimmermann Biodiversity Fellowship, the PADI Foundation, The University of Sydney and the University of Technology Sydney.
We are actively seeking partners and supporters to help us scale this work, expand regional surveys, and invest in long-term coral monitoring infrastructure.
If your organisation or foundation would like to support coral resilience and community-led science, we’d love to hear from you.
Research Impact
This project supports critical marine research led by the University of Technology Sydney and Sydney Institute of Marine Science, with funding from Zimmermann.
Track Distribution
Map where tropical coral species are establishing in temperate NSW waters
Climate Monitoring
Understand how climate change affects marine ecosystem boundaries
Conservation
Inform marine protected area planning and ecosystem management
Have you seen this coral?
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A subtropical species, Pocillopora aliciae, is expanding polewards into temperate reefs along NSW. With your help, we can track where this coral is appearing — or disappearing!
This citizen science project is supported by Zimmerman and led by the University of Technology Sydney and the Sydney Institute of Marine Science.
Your contribution helps scientists:
•Track coral species distribution changes
•Monitor ecosystem health and adaptation
•Understand climate change impacts on marine life
Pocillopora aliciae – Target species for monitoring
How to Contribute
Simple steps to make your diving and snorkelling observations count
1
Record Location
Note your dive/snorkel site using GPS or location name
2
Document Presence
Report whether you saw hard corals – presence or absence both matter
3
Capture Photos
Upload photos and estimate coral size for species identification
4
Submit Data
Add habitat notes and submit to contribute to scientific research
Key Species to Watch
Focus on these subtropical coral species expanding polewards
Pocillopora aliciae
Primary Target Species
Small branching coral with distinctive finger-like projections. Originally subtropical, now expanding polewards into temperate NSW waters.
Plesiastrea versipora
Secondary Target
Dome-shaped coral with distinct growth patterns. Monitor for changes in distribution and abundance patterns.
