IMAS researchers today released 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 Macquarie Harbour and follows previous reports released in 2017 and January and June 2018.
IMAS Research Fellow Dr Jeff Ross, who leads the research project, said the latest report shows that improved DO levels in middle and bottom waters of the harbour seen in late 2017 extended through to the middle of 2018.
“The improvements in DO were reflected in our mid-year survey of seabed conditions,” Dr Ross said.
“There was an increase in the abundance and numbers of benthic species recorded at all five of our study leases and the majority of external reference sites remain in good condition.
“We also continue to see improved conditions in our video assessments of the seabed.
“The presence of Beggiatoabacteria mats and the numbers of dorvilleid worms around leases can indicate higher levels of nutrient enrichment and we have seen a decrease in both.”
Dr Ross said that over recent years a decline in oxygen levels has been observed in spring.
“This year oxygen levels again declined moving into spring but not to the same extent as in previous years.
“In early October there was an ‘oxygen recharge’ of the deeper bottom waters caused by favourable weather conditions and low river flows.
The project is funded by the Australian Government’s Fisheries Research and Development Corporation (FRDC), the Tasmanian Government and Tasmanian Salmon aquaculture companies. The next report will be available in mid-2019.
Click here for the latest report and previous reports on environmental conditions in Macquarie Harbour under the heading 'Salmon'.