Dolphins undeterred by Port construction works

Snubfin and humpback dolphins continue to use Cleveland and Halifax Bays as their playground with population numbers remaining steady over time.

Experts from Flinders University, in collaboration with Southern Cross University and Blue Planet Marine, have been analysing dolphin populations in Cleveland and Halifax Bays since 2019 as part of the Port of Townsville’s $232 million Channel Upgrade project.

Flinders University Associate Professor Guido J. Parra said dolphin populations had remained stable since construction works for the Channel Upgrade project commenced in 2020.

Researchers undertake boat surveys and land-based observations to document snubfin and humpback dolphins, which are both listed as vulnerable species.

“We’re monitoring the dolphin populations to determine if there’s any impact of the construction activities on their distribution, abundance and behaviour,” Prof Parra said.

 “The annual surveys from 2019 to 2021 have shown good news in that the populations of both species, although small, seem to be relatively stable and there has not been any changes in their distribution and abundance.”

Prof Parra said construction activities in 2020 and 2021 had done little to deter dolphins which continued to frolic in waters surrounding the Port.

“Both snubfin and humpback dolphins use the area quite frequently to feed and socialise,” he said.

“They are still using the coastal waters of Cleveland Bay and Halifax Bay, so it seems like the construction activities so far have not had any detrimental impact on the dolphins. Data collected this year and in coming years will be vital to assessing whether there has been any significant impact on the dolphins.”

Port of Townsville Channel Upgrade project Senior Project Director Jason Mahlberg said marine fauna exclusion zones were in place around backhoe dredge Woomera, and crews would immediately stop works if any curious critters ventured too close.

“The Port of Townsville has invested more than $17 million in environmental management and monitoring programs as part of the Channel Upgrade project, including those covering dolphins, turtles, corals, seagrass and water quality,” Mr Mahlberg said.

“We are acutely aware of the sensitive environment in which we operate and these programs not only inform decision making to ensure environmental best practise throughout the duration of the project, but also add to the many years of research the Port and our partners have undertaken into the health of the marine environment in Cleveland Bay.”

A mechanical backhoe dredge is being used to widen Townsville’s 14.9km shipping channel from 92 metres to 180m at the inshore (Port) end, tapering to 120m at the seaward end.

All capital dredge material is being brought back to land for beneficial reuse in a 62ha reclamation area bounded by the new rock wall on the eastern Port boundary.

Dredging is expected to take about two years and upon completion larger ships up to 300m in length will be able to safely access the Port, instead of bypassing Townsville.

The $232 million Channel Upgrade project is a joint project of the Queensland and Australian Governments, and the Port of Townsville, and is a key initiative under the Townsville City Deal.