They were caught red handed by fisheries officers over the weekend with the cuttlefish and one squid.

The officers acted after receiving a call on FISHWATCH.

PIRSA's regional manager central north Paul Faithow said if the men decided not to pay the fine they would face court action.

He said they were currently issued with on the spot fines and will have to appear in Whyalla court if they decide not to pay.

"On the spot fines (are) issued to save the court's time and all the paper work and delays," Mr Faithow said.

"The cuttlefish and squid were dead when our officers confiscated them.

"We will use them as exhibits if the men decide to go to court.

"If the matter is resolved and the catch is in good shape we would sell it but if it's not consumable they would be buried."

A FISHWATCH call led to three people being reported by PIRSA Fisheries for allegedly fishing in the Whyalla cuttlefish closed area over the weekend.

Two of the men were from Renmark and one from Adelaide.

"Twelve cuttlefish were seized and upon further investigation another 51 were located in one of the alleged offender's vehicle," Mr Faithow said.

"A total of 63 cuttlefish and one squid were seized weighing 43 kilograms in total as well as two eskies."

Mr Faithow said the closed area was put in place to protect the unique cuttlefish spawning ground.

He said the closure covers the area of False Bay, just north of Whyalla from the BHP Jetty to the Point Lowly Lighthouse.

"It is an offence to take any cephalopods from within this area, which includes cuttlefish, squid and octopus," Mr Faithow said.

"The closure has been in place for a number of years and has been well publicised.

"It's been very pleasing from PIRSA Fisheries' point of view to see that the local community has taken ownership of the closure and I would like to commend the concerned member of the public who reported this illegal fishing activity.

"Fines (up to) $5000 apply for this type of offence."

Anyone could report illegal fishing activity through the 24 hour FISHWATCH number on 1800 065 522.

Callers can remain anonymous.