A PLAN to restore and rehabilitate seagrass populations across a vast area of Cockburn Sound, 30km south of Perth, is being rolled out by researchers from the University of WA’s Oceans Institute and the Conservation Genetics team at Kings Park, on behalf of industrial giant Cockburn Cement.

The degradation of more than 3000 hectares of seagrasses in the Sound was first noted over 10 years ago and is believed to be due to eutrophication, or the adding of excess nutrients to the water, a process which can occur naturally over time or as a result of local industry and fishery activities.

After years of degradation, plans are being put into action to restore and rehabilitate areas of Cockburn Sound's seagrass.
Image: Informaction

In 2001, Cockburn Cement commissioned a rehabilitation plan focused on the transplanting of genetically-compatible species to those which already exist in the waters at Cockburn Sound, with a view to eventually restoring as much of the lost ecology as possible.

Since then, a research team from UWA and Kings Park has been investigating ways to maximise the program’s success, including the selection of robust seedlings and donor sites.

“Western Australia is one of the areas around the world where seagrasses have been lost in large amounts to eutrophication and Cockburn Sound has been particularly hard hit,” says research leader Professor Gary Kendrick.

“Local seagrasses are used to growing in nutrient-poor waters along the sheltered parts of our coastline, which are the same places that we develop ports and large infrastructure.

“It is this conflict between economic growth and the loss of important ecological habitats that brought about the need for this rehabilitation plan.”

Vital to the program’s success over the next three years will be the selection of correct genotypes to replace those previously lost.

“We have done a lot of work on the ecophysiological requirements to improve the success of the transplants, such as fertilising the sand or adding organic carbon to the sand in the form of broken down seagrass leaves,” Prof Kendrick says.

“We are also starting to get a good understanding of the genetic imperatives for success.

“It is critical that we do not use genotypes outside of the provenance of those we are trying to transplant to as this can weaken the genetic stock and create invasive species issues down the track.”

As seagrasses grow a maximum of just 20cm a year laterally, Prof Kendrick says it can take decades to re-establish an existing meadow.

“It is a very long, drawn-out process with the stochastic factor that we build into any transplant program where, after all the hard work, you can lose it all in just one storm.

“When that happens, it can be very frustrating and quite debilitating to the overall program.

“Our message would be if you do not have to compromise areas of natural seagrass, don’t.

“Nothing is more resilient than an existing meadow.”

Comments (2)

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written by ross dalrymple, September 05, 2010

I grew up in this area and can remember when the rot set in! It was just after the shipyards where built in the sound,you could see a white fungus type coating on the seagrass before it died along with the mussels we used to go there for. I think austral shipyards should be donating some $$$ towards the rehabilitation of the seagrass I would be interested to know if Austral shipyards has put their hand up to acknowledge their part in this! Think of how many tonnes of anti fouling they used and how much of it poisoned the sound

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written by George Brown, September 10, 2010

It is not only Austral, every industry from the plastics and ceramics to the metallurgical and petroleum industriesshould be providing finance, dependent upon their size and how long they have been in the area. More importantly rehabilitation must start NOW!