New Technology to Protect SA’s Giant Cuttlefish Population From Algal Bloom With Bubbles

 

Bubble curtains are the latest technology designed to protect Australia’s iconic giant cuttlefish population from algal bloom.

The South Australian and federal governments are investing nearly $700,000 in a new intervention strategy to protect South Australia’s Giant cuttlefish population from the state’s algal bloom, a phenomenon linked to climate change.

Read more: Giant Cuttlefish in Whyalla – A Guide to Swimming With the Annual Migration

The technology, known as an air bubble curtain, creates an underwater barrier that prevents algae from passing through and mitigates the buildup of algae. The bubbles are created by generators and compressors on land, which pump air through underwater lines and tubing to create a barrier of 2-7 metres deep along the reef.

This is the first time the technology has been used in South Australia and will involve a 200m x 100m air bubble curtain installed on the Cuttlefish Coast in the Upper Spencer Gulf.

‘Protecting this iconic species from the effects of the algal bloom requires innovative approaches and we are hopeful this technology can help preserve one of our state’s truly unique marine animals and the tourism it drives’, said Deputy Premier Susan Close.

The strategy aims to protect about 50,000 to 80,000 cuttlefish eggs and hatchlings. The latest Giant cuttlefish population on the Cuttlefish Coast on the state’s Eyre Peninsula is estimated to be 63,374 compared with 81,420 in 2024.

What is an algal bloom?

An algal bloom is the buildup of populations of algae in freshwater or ocean environments. Generally, algae is good for the environment as a key contributor of oxygen, but this buildup can be cause for concern when particular species of microalgae, which are harmful or toxic, increase in population.

The rise of harmful algal blooms is linked to climate change and is becoming a growing problem for both humans and animals. While not deadly to humans, contact with a harmful algal bloom caused by Karenia mikimotoi can cause flu-like symptoms. 

What’s caused the algal bloom in South Australia?

The algal bloom in South Australia was likely caused by three events:

• flooding along the River Murray in 2022/23
• a cold upwelling bringing deeper, nutrient-rich water to the surface in 2023/24
• and a marine heatwave in September 2024. The heatwave increased temperatures by 2.5ºC above normal levels

Brown foam and dead sea life have been observed along South Australia’s beaches since March 2025, with estimates that over 34,000 animals have been killed by the bloom.

Once the air bubble curtain is installed, the Department of Environment and Water and South Australian Research and Development Institute (SARDI) will monitor the site in consultation with cuttlefish and algae experts to determine when the curtain needs to be operational.

Photos by Jack Breedon