Restoration of degraded marine habitats


Underwater forests are disappearing from temperate coastlines worldwide due to human impacts on coastal ecosystems. Such forests support marine life by providing essential food and shelter to many other species. Although the loss or decline of these habitats from temperate regions could have environmental and socio-economic implications analogous to the loss of coral reefs from tropical regions, widespread declines of canopy-forming seaweeds receives considerably less attention.


A 70 km stretch of underwater forests created by ‘crayweed’ (Phyllospora comosa) disappeared from the Sydney coastline during the 1980s, coincident with a peak in near shore sewage outfalls on our beaches. Despite significant improvements in water quality in Sydney since this time, these forests have failed to recover naturally.


We attempted to restore crayweed forests and the habitat they create for crayfish, abalone, fish and other organisms back into Sydney, by transplanting fertile adults onto reefs where these forests were once abundant. The transplanted crayweed not only survived similarly well to those in natural populations, but they also successfully reproduced, creating a self-sustaining population at a place where this species has been missing for decades. 


These very encouraging results suggest that we may be able to assist in the recovery of these underwater forests back onto Sydney reefs and also potentially enhance biodiversity and recreational fishing opportunities along our coastline. Our methods may also have broader application in other parts of the world to address the global issue of declines of temperate seaweed forests.