Institute for Marine and Antarctic Studies (IMAS) researchers released today the latest results of surveys of environmental conditions in Macquarie Harbour, carried out as part of ongoing monitoring of oxygen dynamics and conditions on the bottom of the harbour.
The report provides an update on the status of dissolved oxygen (DO) and benthic conditions in the harbour and follows previous reports released regularly since 2017.
IMAS Research Fellow Dr Jeff Ross, who leads the project, said the latest report shows that higher oxygen levels in 2018 have led to improved sediment health in the harbour.
“In 2018, oxygen levels in the middle and bottom waters of Macquarie Harbour declined in spring but not for as long, or to the same extent, as we’ve seen in recent years,” Dr Ross said.
“This improvement was reflected in the latest survey of seabed conditions that we carried out early this year.
“The abundance and numbers of benthic species at most sites were in better shape than observed in recent years over the summer months.
“We continue to see improved conditions in our video assessments of the seabed, and the presence of Beggiatoa bacteria mats was also lower this summer compared with previous years.”
Dr Ross said that while the trend of improving harbour health over recent years is encouraging, oxygen levels are still lower than observed historically.
“Our team has just returned from a survey of sediment conditions in June, and another is scheduled for January 2020, and we will also continue to monitor oxygen levels in real time throughout the harbour.
“These observations will provide us with a growing body of data about how well the harbour is recovering following the major deterioration in conditions reported in spring 2016,” Dr Ross said.
The project is funded by the Australian Government’s Fisheries Research and Development Corporation (FRDC), the Tasmanian Government, and Tasmanian Atlantic salmon aquaculture companies.
The next IMAS report will be available in late-2019.
The latest report, together with those released previously, can be found on the IMAS website under the heading ‘Salmon’.