When the Port of Townsville set out to investigate some unusual activity around one of its marine water monitoring sites in Cleveland Bay, it discovered that inquisitive green turtles were showing an interest in the high-tech equipment.
As well as managing the movement of commercial, cruise and military vessels through the 14.9-kilometre channel, the Port monitors marine water quality at five locations in Cleveland Bay. The monitoring equipment is secured to a metre-square frame and lowered approximately three metres to the sea floor. It then provides the Port with data on turbidity (water cloudiness), salinity levels, water temperature and light levels in the large shallow bay.
Port General Manager Infrastructure, Kim Gebers, said that one of the monitoring sites provided an interesting challenge for the team that collects water quality data.
‘By looking at marks on the frame that houses the monitoring equipment, we could see that it was being visited by an unknown marine animal. The possibilities included turtles, crocodiles, sharks or gropers,’ Mr Gebers said.
A Go-Pro camera was installed on the equipment in late 2018 to see if the mysterious visitor could be identified.
‘The Go-Pro was installed in late last year, but due to the recent weather event, conditions in Cleveland Bay made it difficult for our researchers to retrieve the camera and download the footage. When that was done, the mystery was solved.’
The downloaded footage showed that, just 40 minutes after the camera had been activated, two inquisitive green turtles were inspecting the monitoring equipment, even using it as a scratching post.
‘The turtles have actually helped us, as they have given the water quality monitoring equipment a good road-test,’ Mr Gebers said.
‘Based on what we’ve seen, we’ll be modifying the equipment to make it even more robust, also ensuring it is safe for turtles to interact with.’
Green turtles in Cleveland Bay are not only inquisitive; they are also long-distance travellers. A tag found in Cleveland Bay in 2018 was traced to an adult female green turtle tagged whilst nesting at Heron Island near Gladstone in January 2017.
‘This shows that Cleveland Bay is a dynamic habitat for a vast array of well-travelled marine life,’ Mr Gebers said.
‘The more we understand our marine backyard; the better we co-exist with marine fauna like turtles.’
Based on the Go-Pro trial success, the Port will install under-water cameras on monitoring equipment at other locations in Cleveland Bay, including up to seven that are being added as part of the Channel Upgrade Project.
- Cleveland Bay is a large shallow bay that often experiences periods of natural turbidity (water cloudiness) due to wave movements, wind and sediment flows from creeks and rivers as far away as the Burdekin. It usually comes into Cleveland Bay from the South-East.
- Water quality data is collected and analysed by local scientists contracted by the Port.
- The Port of Townsville will introduce wireless technology (telemetry) for future water quality monitoring. This will provide real-time information and reduce the need to lift the equipment from the sea floor for data retrieval.
- Approximately $5 million is being invested in Marine Water Monitoring in Cleveland Bay over a five-year period starting in 2019 as part of the Channel Upgrade Project, as part of more than $10 million of environmental monitoring programs for the Channel Upgrade Project. Port of Townsville Ltd (POTL) has been collecting a range of scientific data from Cleveland Bay for more than 20 years. The data is shared with scientific bodies that have an interest in the marine environment.