Glenn Matkovic and his mates struggled to catch a fish on Sunday but they went home happy after an action-packed day on the water.

The Perth men decided to put their rods down and soak up some sun off Rockingham after an unsuccessful stint of fishing.

“The weather had turned it on and the wind had died right down so we were just drifting and having a chat,” Mr Matkovic said.

“All of a sudden we saw a whale jump out of the water and our eyes lit up. We were just enjoying a relaxing time on the water and then this whale breached about 100m or 150m away from the boat.”

Camera Icon The incredible sight off the WA coast. Credit: Glenn Matkovic

The adult whale that breached had a calf alongside it.

The anglers stayed in the area for half an hour before heading for another fishing spot near Carnac Island.

They were on their way when they saw what appeared to be a small reef in the distance.

“As we got a bit closer we realised it was a whale carcass,” Mr Matkovic said.

“Then we saw the sharks. I stood on top of the boat and had a bit of a count and there was at least 30 of them, I reckon.

“They were just everywhere.”

Camera Icon A group of mates had a close encounter with several sharks as they fed on a whale carcass off Carnac Island. Credit: Glenn Matkovic

Mr Matkovic said the biggest shark in the feeding frenzy would have been a tiger shark measuring about 4.5m.

“There were a lot of little bits of whale floating around and sinking down, so there were a lot of seagulls hanging around,” he said.

“A couple of sharks nearly got the seagulls as well.”

The men stayed with the carcass for about two hours — and they were still buzzing the morning after.

“It’s something you don’t see every day so I guess we wanted to make the most of it,” Mr Matkovic said.

“The sharks were just doing their thing. It was like we weren’t even there.”