A comprehensive report released in the Mackay Whitsunday Region this week provides a better understanding of the health of mangroves in the Bassett Basin.

The Regional Coordinator of the Mackay Whitsunday Natural Resource Management (NRM) Group, Kelly Flower said the report, developed in conjunction with Central Queensland University (CQU) Mackay, investigated changes in herbicide levels in Pioneer River mangrove sediments and their relationship to mangrove health.

Central Queensland University researcher Dr Judith Wake said a key finding was that “the overall health of the grey mangroves in the Pioneer River Estuary is good”.

“There is evidence of past dieback of the mangroves in the Pioneer River from Fursden Creek downstream to Macalister Street and in the Bassett Basin, but there is no evidence of sick trees at present".

“The levels of herbicides in the sediments in the Bassett Basin have declined, however higher levels of diuron were found in sediments near the mouth of Fursden Creek than previously recorded for any sites,” said Judith.

"This project was designed to address some of the deficiencies in knowledge relevant to the mangrove dieback problem identified by Mackay Whitsunday NRM Group’s ‘Mangrove Dieback Working Group’,” Mrs Flower said.

Mrs Flower said this report greatly increases our understanding of the health of the mangrove communities in the estuaries in the Mackay region.

Their health has been of concern since the 1990s when dieback of the grey mangrove Avicennia marina was observed by recreational anglers.

The levels of herbicides in the sediments at Sandfly Creek suggest that non-agricultural inputs of herbicides also need to be addressed.

Close monitoring of changes in mangrove health in relation to future rainfall events is needed to accurately determine the role of runoff in mangrove dieback.

According to the Mackay Whitsunday NRM Group, a more sensitive and objective measure of assessing mangrove health is imperative if changes in mangrove health are to be assessed with the accuracy required to set trigger values for pollutants.

For more information on mangrove dieback please contact Dr Judith Wake at CQU Mackay campus on 4940 7850.