
Imagine a vast underwater forest, its tall, swaying kelp providing a home for fish, lobsters, and other marine creatures. Now, imagine it being replaced by a barren, lifeless underwater desert. This isn’t the plot of an ocean-themed disaster movie—it’s happening right now in the waters of southern Australia. The culprit? A tiny but uncontrollable sea creature: the long-spined sea urchin.
What’s Happening to the Kelp?
Kelp forests are like the rainforests of the sea. They’re incredibly important ecosystems that support marine life, protect coastlines, and even help fight climate change by absorbing carbon dioxide. But in places like Tasmania and along the Great Southern Reef, these lush underwater habitats are disappearing.
Why? Because sea urchins, particularly the long-spined sea urchin (Centrostephanus rodgersii), are devouring them. These spiky little creatures feast on kelp, and when their populations explode, they can strip entire areas of this vital seaweed, leaving behind what’s known as “urchin barrens”—vast stretches of rocky sea floor, devoid of life.

Why Are Sea Urchins Taking Over?
The sea urchin problem didn’t come out of nowhere. It’s a perfect storm of human and environmental factors:
- Warming Oceans: The long-spined sea urchin is native to warmer waters further north, but as ocean temperatures rise due to climate change, they’ve expanded their range southward into cooler waters. In their new environment, they’ve found plenty of kelp and few natural enemies.
- Fewer Predators: In healthy ecosystems, predators like the southern rock lobster keep sea urchin populations in check. Unfortunately, overfishing has reduced the numbers of these predators, giving urchins free rein to multiply.
- Marine Heatwaves: Events like the 2011 marine heatwave off the coast of Western Australia have severely weakened kelp forests, making it easier for sea urchins to move in and finish the job.

Why Does It Matter?
The loss of kelp forests is a big deal. These underwater ecosystems provide food and shelter for countless marine species, many of which are important to local fisheries. Without kelp, biodiversity plummets, and the marine environment becomes less resilient.
Kelp also plays a crucial role in combating climate change. Like trees on land, kelp absorbs carbon dioxide from the atmosphere. Losing these forests means losing a valuable natural ally in the fight against global warming.

What’s Being Done to Help?
Thankfully, people aren’t sitting idly by while the kelp disappears. Researchers, conservationists, and local communities are working on solutions, including:
- Restoring Predators: Efforts are underway to rebuild populations of natural sea urchin predators, like the southern rock lobster, to keep urchins in check.
- Urchin Culling: Divers are being employed to manually remove sea urchins from affected areas. In some places, urchins are even being harvested and turned into a delicacy.
- Kelp Restoration: Scientists are experimenting with ways to replant kelp in areas that have been stripped bare, including using heat-resistant strains of kelp that can better survive warming waters.

How You Can Help
Protecting kelp forests might seem like a job for scientists and conservationists, but there are ways everyone can contribute:
- Eat Sustainably: Choose seafood from sustainable sources to help protect marine ecosystems and reduce overfishing. Importantly you are encouraged to see sea urchin. Not only is it delicious but if we can raise the price of sea urchin as a commodity in Australia we can help support the local urchin and abalone divers to maintain their local kelp forests.
- Reduce Your Carbon Footprint: Drive less (even better switch to an EV), use energy-efficient appliances, and support renewable energy to combat climate change.
- Spread Awareness: Share stories like this one to help others understand why kelp forests are so important.

The Bottom Line
The loss of kelp forests in southern Australia is a reminder of how interconnected our planet’s ecosystems are. While sea urchins may be small, their impact is anything but. By taking action to restore balance in the ocean, we can ensure that these incredible underwater forests have a fighting chance to thrive once again.
Ocean Film Festival 2025
This year in the line up, ‘White Rock’ is a film all about the Kelp Crisis.This gripping documentary follows passionate marine conservationists and divers who are fighting back against the invasive species, transforming an environmental threat into a sustainable solution.
Through stunning underwater cinematography, the film reveals how climate change is destroying marine ecosystems. The divers not only document the destruction but also offer hope by harvesting sea urchins and promoting them as a delicious culinary option, creating an innovative approach to marine conservation.
Secure your tickets to this year’s Ocean Film Festival Now – https://oceanfilmfestivalaustralia.com.au/tickets/
All images above are supplied from the film ‘White Rock’
