Catherine O’Leary spotted the two-metre Grampus griseus washed up on the beach on Monday, about 300m south of the former Gerroa tip location.

She described the animal as “beautiful”.

“It’s really sad that it’s dead,” she said.

NPWS area manager Nowra Greg Tedder said the animal was identified as a male.

“At about two metres long it would indicate it is not an old animal,” he said.

“They can grow up to 4.1m and weigh often more than 230kg.

“They are relatively common but more found in deeper tropical waters.

“They are more an offshore animal that lives off the continental shelf, feeding on small fish, octopus and cuttlefish.

“They start off a dark grey colour and as they become older get whiter and they usually have lots of scarring on their bodies. They squabble a lot between themselves and often inflict bites on each other.”

He said they have a distinctive bulging head and are related to pilot whales, better known as false killer whales.

The last known Risso’s dolphin to wash up on a local beach was at Durras in March this year.

Due to the creature’s location, which is in a low visitation area well away from homes, the carcass will be left where it is. 

It is hoped the carcass may be taken out to sea on a high tide or gradually decompose on the beach.

Beach walkers are asked not to touch the carcass or interfere with it in any way and to keep a reasonable distance.

As the carcass decays there may be odours especially in the initial stages.

If you see a distressed or stranded sea mammal ring the organisation for the Rescue and Research of Cetaceans in Australia (ORRCA) on 9415 3333 and NPWS on 1300 361 967.