Local divers are concerned that giant Australian cuttlefish are yet to been seen in their usual numbers in upper Spencer Gulf this season.

Point Lowly near Whyalla in South Australia is the only place in the world where the giant cuttlefish usually breed in big numbers.

It is now the breeding season but a tourist to the area, Matthew Pearce, said he did not see any cuttlefish during a dive in the area.

"Didn't even see a single one," he said.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 6 minutes 9 seconds 6 m Diver Tony Bramley voiced his fears to Nicola Gage ( News Online ) Download 2.8 MB

"I was a bit upset I didn't get to see that, especially in large numbers, that would have been amazing."

The numbers were also sharply down last year and local commercial diver Tony Bramley fears it could be the end of a unique breeding phenomenon.

"I'm hoping desperately that I'm wrong and that there will be a late influx of animals," he said.

Greens MP Mark Parnell said any permanent loss of the breeding event would be devastating.

"Is it predation? A natural occurrence in the environment? Is it overfishing somewhere else? Is it pollution in this fairly industrial landscape? What is it?" he asked.

"It's not good enough to simply count the numbers of cuttlefish. They need to get to the bottom of why numbers are in such sharp decline."

The Greens want an emergency task force set up to investigate why the normal breeding appears not to be happening.

The SA Government recently extended a protection zone around the cuttlefish spawning area.