Perth's beaches will soon be home to seals and sea lions as they rest before the breeding season, prompting a warning from the Department of Parks and Wildlife.
Australian sea lions, New Zealand fur seals and sub-Antarctic fur seals will be lazing at beaches in the Perth metro area and Southwest region in coming weeks.
The department is reminding people to leave the seals undisturbed and keep a safe distance from them.
Wildlife officer Cameron Craigie said people often attempt to "rescue" young seals and sea lions thinking they are sick or abandoned, when they are actually resting.
"Such intervention can cause these animals to become highly stressed and can lead to a deterioration in health, while feeding them inappropriate foods can cause sickness and in some cases death," he said.
Mr Craigie said the best thing to do is leave them alone, particularly as some sea lions can weigh up to 200kg, have large canine teeth and can become aggressive and bite.
Australian sea lions are the rarest in the world and are protected under conservation laws.
Male sea lions spend time resting in areas offshore from Perth - while the females tend to stay on islands - to get ready for the breeding season in the Jurien Bay area.
The Abrolhos Islands off Geraldton are also a key breeding area.
