COTTESLOE and North Cottesloe Beach are closed following a shark sighting.
The Surf Life Saving Helicopter spotted a 2.5m unknown species of shark at 11:378am.
It was swimming about 80m offshore.
The helicopter also spotted a 1.5m unknown species of shark at 11:49am at The Basin about 800m off Rottnest Island.
— Surf Life Saving WA (@SLSWA) November 3, 2017