Lifting the (bubble) curtain on cuttlefish protection

It’s the lat­est inno­va­tion in cur­tain tech­nol­o­gy and no it isn’t avail­able at your local Spot­light store.

The SA and fed­er­al gov­ern­ments have team up to invest in some­thing called a ​‘bub­ble cur­tain’ and its part of an inter­ven­tion strat­e­gy aimed at safe­guard­ing Australia’s icon­ic giant cut­tle­fish pop­u­la­tion from the algal bloom.

What is it and how does it work?

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 laid over winter.

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 been used in South Aus­tralia before, and the instal­la­tion will be an 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 West­ern Aus­tralia 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.
 

When will it be used?

The air bub­ble cur­tain will only be turned on if and when the bloom is detect­ed nearby.

At the moment, the algal bloom is present on the west­ern side of Spencer Gulf and is mov­ing north, but has not arrived at Point Lowly.

The Depart­ment for Envi­ron­ment and Water and SAR­DI are mon­i­tor­ing the site in con­sul­ta­tion with cut­tle­fish and algae experts to deter­mine when the cur­tain needs to be turned on.

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 too.

Cut­tle­fish sea­son wrap-up

The giant cut­tle­fish is an icon­ic South Aus­tralian marine ani­mal and they are of spe­cial sig­nif­i­cance to those of us that live 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 states tru­ly unique marine ani­mals and the tourism it drives.

The cut­tle­fish breed­ing sea­son has now fin­ished, and most of the giant cut­tle­fish have left the area. Cut­tle­fish nat­u­ral­ly die after spawn­ing, and this should not be linked to the algal bloom. So, it is nor­mal for dead cut­tle­fish to wash up along the coast.

Cut­tle­fish eggs will start to hatch in late Octo­ber through November.

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.
 
Relat­ed stories

• Vis­it the Algal Bloom Update site for news, updates and offi­cial advice
• South Aus­trali­a’s algal bloom — all your ques­tions answered
• What it’s like to go swim­ming with the Giant cuttlefish