Restoration Project

University of New South Wales - Long Bay

Restoration Objective:

This experiment was conducted to determine whether Sydney's rocky shores are now suitable for the survival and recruitment of crayweed, and to assess the possibility of restoring these reefs to their natural states.

Site Selection Criteria:

Sydney sites were chosen that had similar conditions to donor sites and that historically hosted crayweed forests.

Cause Of Decline:

‘Crayweed’ forms dense forests on shallow reefs all the way from Port Macquarie to Tasmania. Crayweed (scientific name Phyllospora comosa) used to also be very abundant along the Sydney coastline, but sometime during the 1980s it disappeared completely from the metropolitan area between Palm Beach and Cronulla. The high volumes of poorly treated sewage that were pumped directly onto Sydney’s beaches and bays before the 1990s likely caused this decline. The problem is that although water quality in Sydney has improved dramatically since the establishment of deep ocean sewage outfalls, the crayweed forests have not returned on their own.

Key Reasons For Decline:

Water Pollution

Scientific Paper

Towards Restoration of Missing Underwater Forests

A.H. Campbell, E.M. Marzinelli, A. Verges, M.A. Coleman, P.D. Steinberg, , Plos One, Vol. 9.https://doi.org/10.1371/journal.pone.0084106

Organisations:

University of New South Wales

Australia

UNSW is an international university based in Sydney, Australia. It is the home of the Center for Marine Science and Innovation and partner institute with the Sydney Institue of Marine Scince. UNSW is blessed to be situated less than 10 minutes away from beautiful forests of Ecklonia radiata.

Operation Crayweed

Australia

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

9th Aug 2012 – 17th Jan 2013

Action Summary:

Crayweed was transplanted from nearby donor populations to two sites in Sydney that historically had crayweed beds. Crayweed was sampled haphazardly so that males and females were transplanted evenly. The condition and survival of adult crayweed and recruitment of propagules was then measured over several months.

Lessons Learned:

The limited survival of Crayweed at some sites may be enhanced by restoring larger patches of crayweed to reduce the effects of herbivory. The location of crayweed recruits mainly under the adult canopy indicates this may also improve crayweed survival, and be another limitation preventing crayweed from returning to its historical distribution.

Project Outcomes:

Survival of adults transplanted from Cronulla to Long Bay was 70%, which did not differ from that of undisturbed individuals or procedural controls. Survival of individuals transplanted from Palm Beach to Cape Banks was 40%, which was lower than that of controls. This indicates some sites in Sydney are now suitable for Crayweed restoration. In the second experiment, survival of transplanted individuals was 70%, and donor population did not change survival rates. Survival rates at Little Bay over 12 and 17 months was 50% and 20% respectively. Crayweed successfully recruited at one site, Long Bay.

Key Reasons For Decline:

Water Pollution

Area of Restoration (In Square Metres)

5.5

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Percent Survival

70.36290323
%
100
%
Transplant Info:
Adherence Method:Cable Tie
Life Stage:Adult
Source:Culture
Costings:
Cost Currency:USD

Observation Date

9th Aug 2011 – 17th Jan 2012

Action Summary:

Crayweed was transplanted from nearby donor populations to two sites in Sydney that historically had crayweed beds. Crayweed was sampled haphazardly so that males and females were transplanted evenly. The condition and survival of adult crayweed and recruitment of propagules was then measured over several months.

Lessons Learned:

The limited survival of Crayweed at some sites may be enhanced by restoring larger patches of crayweed to reduce the effects of herbivory. The location of crayweed recruits mainly under the adult canopy indicates this may also improve crayweed survival, and be another limitation preventing crayweed from returning to its historical distribution.

Project Outcomes:

Survival of adults transplanted from Cronulla to Long Bay was 70%, which did not differ from that of undisturbed individuals or procedural controls. Survival of individuals transplanted from Palm Beach to Cape Banks was 40%, which was lower than that of controls. This indicates some sites in Sydney are now suitable for Crayweed restoration. In the second experiment, survival of transplanted individuals was 70%, and donor population did not change survival rates. Survival rates at Little Bay over 12 and 17 months was 50% and 20% respectively. Crayweed successfully recruited at one site, Long Bay.

Key Reasons For Decline:

Water Pollution

Area of Restoration (In Square Metres)

6

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Percent Survival

70.04
%
100
%
Transplant Info:
Adherence Method:Cable Tie
Life Stage:Adult
Costings:
Cost Currency:USD