Operation Crayweed: How scientists are reviving Sydney’s lost underwater forests

Sydney’s iconic coastline witnesses a remarkable ecological return. After being devastated by pollution, the forests murmured for sea life and coastal health were meticulously restored through a pioneering project known as the Crayweed operation. This effort not only brings back a lost habitat, but also offers a plan for global maritime restoration.

The Crayweed operation, which was initiated ten years ago, is a collaborative project managed by scientists from New South Galler University and other institutions and with the support of state institutions and community volunteers. Mission: Restore 60 hectares of Crayweed forest to Sydney’s shallow rocky reefs.

Crayweed (Phyllospora comosa) A large, gold-brown seaweed on the southeastern coast of Australia. These underwater forests are very important: carbon amounts, Abalone, rock lobsters and numerous fish species, such as shelter and nursery areas for sea life, and support coastal biodiversity and food networks.
However, in the 1980s, a 70 -kilometer south of Sydney’s reefs reached out and coincided with discharge to the ocean of the untreated sewer. The loss was not greatly noticed at that time, but its effects fluctuated throughout the ecosystem, affected fishing, reduced biological diversity and reduced the natural flexibility of the coastline.

How to work

• Selection and planting: Healthy male and female murmuring collects from natural populations and depends on biologically disintegrated mats attached to the selected reef fields.
• Natural Reproduction: Male plants secrete sperm into the water by fertilizing the eggs from nearby females. The emerging children or “Craybies bind themselves and begin to grow.
• Removal of mats: After the installation of young music, the mats are removed and allows the forest to expand naturally.

This approach, known as “applied nuclei, creates a small, self -sustainable patches that function as seed sources for more natural spread.

Results and effect

Since its establishment, the Crayweed operation has targeted 16 sites during Sydney’s reefs. Seven of them now support the self -sustaining break forests, which cover more than two hectares. In particular, new sites added in 2024 – such as Dee WHY and South Maroubra showed rapid growth, South Maroubra seeing more than 1,500 baby food in the beginning of 2025.

Microscopic organisms and other marine life are already returning and indicate the gradual restoration of the wider ecosystem. Biodiversity in the restored areas begins to resemble the forests of natural biraves, support lock fish and shellfish populations and increase fishing opportunities for entertainment purposes. All restoration attempts did not succeed. Some areas have fought at high levels of herbivorous (grazing by sea animals) or burial in sand. The adaptable approach of the project – to detect different land sizes, donor areas and genetic diversity – is the key to understanding what directs successful restoration. It is about rebuilding an entire ecosystem and the services it provides. The founding partner of the project. Adriana Vergés explains, “We are not just introducing a species again; we develop the entire ecosystem,” he explains.

Next way

The three new sites added in 2024 and the Crayweed operation is increasing their efforts with ten more plans for the next two and a half years. The project has also become a model for the participation of the people who combine science, community action and creative social assistance to inspire support for sea protection.