Operation Crayweed - Whale Beach

Restoration Project

Operation Crayweed - Whale Beach

Restoration Objective:

The aim of this study was to use genomics to determine the influence of transplant donor site on the success of restoration of Phyllospora comosa, in order to improve restoration outcomes and restore historical populations.

Site Selection Criteria:

Sites were selected that were moderately exposed with large, flat boulders at 4-5m depth and no crayweed present.

Cause Of Decline:

Crayweed (Phyllospora comosa) is a dominant macroalga that forms extensive underwater forests along the south-east coast of Australia. Phyllospora underpins coastal biodiversity and valuable ecosystem functions and services such as secondary production and nutrient cycling, but disappeared from 70 km of Sydney's coastline in the 1970–1980s. While this decline was likely due to poor water quality, which has since improved, Phyllospora has not returned naturally. This is likely due to recruitment limitation.

Key Reasons For Decline:

Water Pollution

Scientific Paper

Using genomics to optimise and evaluate the performance of underwater forest restoration

A. Vergés, Wood G., Marzinelli E.M., Campbell A.H., Steinberg P.D., Coleman M.A
Journal of Applied Ecology.


The aim of OPERATION CRAYWEED is to bring crayweed back to reefs where it once flourished and to re-establish this essential habitat and food source for Sydney’s coastal marine biodiversity.

Scientists at Operation Crayweed have already developed a successful method to create crayweed forests on reefs where they were once dominant, by transplanting healthy, fertile adults from existing populations and attaching them to deforested rocks using biodegradable mesh drilled into the bottom. There, they survive, they thrive and they start having sex - a lot of sex.

Site Observations:

Observation Date

15th Oct 2017 – 13th Apr 2018

Action Summary:

Algae were transplanted over 1-3 days by cable-tying individuals in natural densities (15 algae/m2) to 6 x 2m2 plastic mats per site that had been attached to the rocky reef. Mats were placed on top of bare rock or turfing corallines, 0.5 - 5m apart depending on substrata availability. Individuals from the two donor sites were evenly distributed (mixed) across each of the mats at each site, and identified using cable ties of different colours.

Lessons Learned:

Restoration was successful, and crayweed recruits were also observed.

Project Outcomes:

Between 13-40% of transplanted adults remained in restored sites after 6 months and c. 8% remained across all sites after 9 months. At 6 months, survival of adults sourced from BB (31.3%, SE 3.56%) was significantly higher than those sourced from SP (19.1%, SE 3.56). Most of the remaining algae had higher levels of epibiosis than when transplanted (<5%), with significantly higher epibiosis on adults sourced from SP (30.24%, SE 3.30%) than from BB (22.92%, SE 3.30%). Both of these patterns were consistent across all sites.

Key Reasons For Decline:

Water Pollution

Area of Restoration (Ha)


Indicator Data:


Ending Value:

Starting Value:

Percent Survival