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 January, May and September 2017, and January 2018.
IMAS Research Fellow Dr Jeff Ross, who leads the research project, said the report released today shows improved DO levels in middle and bottom waters of the harbour as a result of oxygen ‘recharge events’ caused by favourable weather conditions and lower river flows over the last eight months.
“These improvements in DO were most notable in early November 2017 and January and March this year as strong north westerly winds and lower river flows resulted in more oxygen being mixed into the water column,” Dr Ross said.
“However, this report shows little change from the low levels of faunal abundance and numbers of benthic species recorded in the deeper central area of the harbour in our previous survey.
“Following the sustained period of DO recharge over summer and early autumn it will be important to see whether there is a return to higher faunal abundances and number of species recorded in our next surveys this winter.
“Ultimately, as we have noted previously, sustained faunal recovery in the deeper central region of the harbour will most likely depend on the return of more stable and higher DO concentrations in mid-bottom waters throughout this year,” Dr Ross said
The latest report, together with those released previously, can be found can be found on the IMAS website under the heading Salmon.