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Scientists confident in health of Geographe Bay Seagrass

20 February, 2019

Scientists undertaking seagrass research in Geographe Bay last week have been pleased with preliminary results following two days of diving and sampling.

Each summer, scientists from Edith Cowan University join divers from the Department of Biodiversity, Conservation and Attractions to monitor the seagrass meadows at eight sites across Geographe Bay.

Results this year are yet to be fully assessed, but Associate Professor Kathryn McMahon from Edith Cowan University says shoot density of seagrass has either improved or stayed the same as 2018 numbers.

“We were very pleased with the seagrass health this year. The Busselton Jetty and Port Geographe sites showed increases of 23% and 28% respectively, which is fantastic” said Associate Professor McMahon.

The Port Geographe improvements are particularly pleasing, and may be attributed to reduced seagrass wrack accumulation following the marina realignment.

While in previous years epiphyte growth (algae covering the seagrass leaves) has been high at several sites, this year saw a reduction across all sites.

“In previous years the Buayanup and Vasse Diversion Drain sites had ‘high’ algal growth on the seagrass leaves, but in 2019 only a ‘low’ cover was observed” said Associate Professor McMahon.

The “Keep Watch” seagrass monitoring project is coordinated by GeoCatch and funded by Water Corporation, and has been running since 2012. GeoCatch Chair Felicity Bradshaw says the program helps determine if impacts such as poor water quality from the catchment are affecting seagrass health.

“Nutrients enter the Bay from rivers and drains from a variety of sources including garden and agricultural fertilisers” said Felicity.

“Seagrass is a good indicator of the health of the Bay, so it is fantastic that we can keep this work going to ensure Geographe Bay is protected into the future”

The success of the annual monitoring would not be possible without the partnership between GeoCatch, Edith Cowan University, the Department of Biodiversity, Conservation and Attractions and funding support from Water Corporation.

Results from this year’s monitoring will be analysed and put in a report on the GeoCatch website. Reports from previous years can be found on the website