Update, 3.20pm: A headless tiger shark was pulled from the water at Cottesloe Beach this morning.
Lifeguards pulled the 2.5m carcass on to the Cottesloe Beach groyne just before 10.30am.
A Surf Life Saving WA spokesman said the lifeguards thought a fisherman had probably chopped off the animal’s head before throwing it back into the water last night.
Fisheries officers, water police and rangers were at the scene.
A fisheries spokeswoman said it was the responsibility of the local council to dispose of the carcass. Cottesloe rangers have since removed the shark.
The Department of Fisheries said the shark was protected due to its size and Cottesloe rangers have reminded people fishing for sharks in the area is illegal.
In the South West, the Westpac Helicopter has sighted eight hammerhead sharks at Bunker Bay. The sharks range from 2m to 3m and the beach has been closed.
A 4m white shark has also been sighted in nearby Busselton, 20m from the shore in front of the Busselton Hospital. The water has been cleared.
Swimmers in Perth have been warned after the Westpac Helicopter has sighted a 2m hammerhead shark between Swanbourne and City Beach. The beach remains open.
The helicopter has also sighted a 3.5m shark heading into Porpoise Bay at Rottnest. The shark was last seen 200m from the shore at about 3.05pm.
A 3m shark was sighted feeding on bait fish between Trigg and Scarborough beaches about 1pm. The water was been cleared but the beach was reopened at about 2.30pm.
Last week up to 16 tiger sharks were spotted feeding off a dolphin carcass metres from the shore at Trigg Beach.
The incident caused the closure of Trigg and Scarborough beaches for several hours.
Earlier today, a 3m shark was spotted just 20m offshore at Margaret River surfing spot Injidup Point.
The shark was seen heading north from the south-west rescue helicopter.