Innovative investment aims to protect giant cuttlefish
Friday 29 August 2025 Biosecurity
The State and Federal Governments are investing in an intervention strategy aimed at safeguarding Australia’s iconic giant cuttlefish population from the algal bloom.
A 200m x 100m air bubble curtain will be installed on the Cuttlefish Coast in the Upper Spencer Gulf with an aim to protect about 50,000 to 80,000 cuttlefish eggs and hatchlings.
Air bubble curtain technology creates an underwater barrier that can mitigate the effects of algal blooms by disrupting the movement of algae, preventing it passing through the bubble curtain. Bubbles are created using land-based generators and compressors to pump air through underwater feeder lines and tubing to create a buffer zone two metres to seven metres deep along the rocky reef.
Air bubble curtains have never before been used in South Australia, and the installation will be important trial of this technology.
It works as a preventative barrier, and is therefore ineffective for areas where the algal bloom has already been detected.
While bubble curtains have been successfully trialled in WA to protect kelp from fish, there are limitations to where and when they can be used. They won’t, for example, protect oysters from brevetoxins, nor can they be deployed across vast areas or in intertidal zones.
Installation of the air bubble curtain at Point Lowly, by East West Dive and Salvage, is expected to be completed this weekend, weather permitting.
The algal bloom is present on the western side of Spencer Gulf and is moving north, but has not arrived at Point Lowly.
The air bubble curtain will only be operational if and when the bloom is detected nearby.
The Department of Environment and Water and SARDI will monitor the site in consultation with cuttlefish and algae experts to determine when the curtain needs to be operational. Cuttlefish season has closed for the year.
Marine parks and harbour restrictions will be enforced through a 50 metre perimeter around the curtain. The site will be monitored by cameras and surveillance.
Cuttlefish eggs will start to hatch in late October through November. Dead cuttlefish are anticipated to wash up on the coast at the completion of the spawning season in coming weeks.
This is part of the natural cycle where cuttlefish die after spawning and should not be attributed to the algal bloom.
The latest giant cuttlefish counts show an estimated population at Cuttlefish Coast of 63,374, compared to 81,420 in 2024.
The lowest cuttlefish population estimate was approximately 13,500 in 2013. The highest population estimate on record is 247,146 in 2020.