Conservation Council CEO Tim Kelly says the Government needs to announce a plan of action and immediately put the cuttlefish on a protected species list.
Mr Kelly says the Government, scientists and others need to pool their resources and knowledge to help save the cuttlefish, reports ABCNews.
"I think it would be really good if the Government released its current action plan for the recovery of the cuttlefish straight away, certainly as soon as possible, and commit to a really solid response to this," he said.
"This is a very serious problem - we don't want to lose species in South Australia."
In recent years divers and conservationists have found fewer cuttlefish aggregating for the breeding season in the region.
The species is currently protected in an exclusion zone near False Bay and Point Lowly.
Mr Kelly says cuttlefish need to be protected across the middle to Upper Spencer Gulf region, to try to restore the population.
"At the moment, outside the exclusion zone, people can still fish 15 cuttlefish per person or 45 per boat per day and we're saying this population is in crisis and it needs protection right now, so everything that can be done must be done urgently," he said.
Fisheries Minister Gail Gago says the study's results are not yet ready for release.
She says a working group is receiving input from the conservation council and local councils and will initiate a discussion soon.
Ms Gago also says a protected area for the cuttlefish has been extended.
