Wetlands Australia 32: Working together to assist seagrass recovery at Shark Bay

Authors: Elizabeth Sinclair and Gary Kendrick (The University of Western Australia) and Amrit Kendrick

Western Australia’s Shark Bay, or Gutharraguda (two-waters), is recognised on the World Heritage List as a place of exceptional natural features. The bay’s 13 species of temperate and tropical seagrasses provide food and habitat for dugongs, turtles and sharks, as well as many fish species.

The large temperate seagrasses, Amphibolis antarctica and Posidonia australis, have been historically dominant, creating persistent meadows of some 4000 square kilometres. They are also responsible for the accumulation of the Wooramel Banks, limiting water exchange with Hamelin Pool and creating the hypersaline environment suitable for stromatolites.

Aerial photo of Shark Bay seagrass beds. Photo: George Steinmetz, 2018.

In the summer of 2010-2011 a marine heatwave devastated Shark Bay’s seagrasses. Initial defoliation of A. antarctica followed by rhizome death in 60–80% of the bay’s meadows caused disruption to the ecosystem which is still ongoing. Valuable scallop and blue swimmer crab fisheries were closed and sea snakes, dolphins, and culturally significant species such as green turtles, dugongs, and cormorants experienced large declines.

A research team from The University of Western Australia supported by the National Environmental Science Program (NESP) Marine Biodiversity Hub is working to assist the natural recovery of seagrasses at Shark Bay. Project leader Elizabeth Sinclair is assessing genomic diversity in both seagrass species, and John Statton is working on recovery techniques with Traditional Owners. Six Malgana Indigenous rangers have now completed training in conservation and land management.

In August 2019, researchers and Malgana rangers spent time together at Shark Bay, collecting seedlings, observing fish and snorkelling over a trial seagrass planting. Rangers shared memories of being on the water with their uncles and grandfathers, and scientists shared discoveries about seagrass lifecycles, flowering, seeds and seedlings.

Aboriginal Elders performing a traditional ‘Welcome to Sea Country’. Photo: Amrit Kendrick, 2019

Future work in collaboration with Traditional Owners will involve trialling methods or transplanting and seeding sea grass, developing nature-based solutions to sea grass loss caused by climate-change related seagrass loss, and planning an ‘Arts meets Restoration Science’ Seagrass Festival in Denham to celebrate and share the environmental and cultural knowledge.

The Malgana ranger program is supported by Yamatji Marlpa Aboriginal Corporation, through funding from the Western Australian Government Department of Biodiversity, Conservation, and Attractions.

Further information

• NESP Marine Biodiversity Hub project - Project E6 – Assisting the restoration of seagrasses at Shark Bay