Authorities should throw the book at a group of youths who attacked a pod of dolphins in South Australia, Project Dolphin Safe president Aaron Machado says.

"We're calling for national parks to actually endorse and enforce the regulations they make," Mr Machado said today.

A fisherman told the Marina Sports Association this week that he saw a group of youths lure dolphins into the Whyalla Marina with fish about two weeks ago and attack them with rocks.

Marina Sports Association vice-president Wayne Carn described the school holiday attacks as "disgusting".

"It's illegal to feed dolphins and they're such a lovely creature, it's hard to stop anyone," he said.

Mr Machado said authorities should enforce regulations to make an example of the youths involved in the Whyalla incident.

People feeding dolphins face serious fines, while acts of animal cruelty attract up to four years' jail.

"People need to be educated on the long-term adverse affects of feeding animals," he said.

"Much of the public doesn't take these regulations seriously."

AAP