Standard Presentation (12 minutes) Australian Marine Sciences Association 2025 Conference

Optimizing Marine Forest Restoration in Southern Port Phillip Bay, Victoria, Australia. (120213)

Jacqui B Pocklington 1 , Paul Carnell 2 , Jasmine Bursic 1 3 , Cayne Layton 4 , Prue Francis 1 3 , Josh McIntyre 1 3
  1. Deakin Marine, Deakin University, Queenscliff, Vic, Australia
  2. Centre for Nature Positive Solutions, , RMIT, Melbourne, VIC, Australia
  3. Deakin University: School of Life and Environmental Sciences, Curlewis, VIC, Australia
  4. Blue Conservation Services, Hobart, Tasmania

The Kelp Ecklonia radiata is being lost from subtidal reefs in Port Phillip Bay (Victoria, Australia), due to overgrazing from the native sea urchin Heliocidaris erthryogramma. Loss of this key
habitat-forming alga has led to a loss of the marine communities they support, and the development of ‘barrens’ habitat. For restoration of marine forests, a variety of approaches can
be undertaken. We combined urchin density reduction (maintained at <2/m2) with out-planting of kelp grown on green gravel in two separate trials. In Trial 1, (as part of a large multiagency
project) Ecklonia individuals were found to have survived for over 1 year, with several attaching to the seabed, and some with reproductive sori.

In Trial 2, our out-planted kelp was split into two different gravel densities and two different life stages. After 6 weeks, early successional ‘turf’ algae were abundant on green gravel and
surrounding reef, kelplings couldn't yet be observed. Monitoring for Trial 2 will continue, and the results of both trials will be discussed in the context of optimizing marine forest restoration.