The sighting of a great white shark near the popular tourist town of Exmouth in Western Australia has created a flurry of excitement online, with one researcher describing it as "weirdly fantastic".

Angler James Fitzgerald was fishing in the Exmouth Gulf, 1,200 kilometres north of Perth, when a shark approached his tinny on Friday.

Mr Fitzgerald filmed the encounter and the video has gathered millions of views on social media.

University of Western Australia Professor of Marine Science Jessica Meeuwig said it was rare to see white sharks in warmer waters and described the sighting as "weirdly fantastic".

"It is a bit unusual," she said.

The Sharksmart website, which tracks shark activity in WA, listed Friday's sighting as a "4.0m white shark sighted 500m offshore near Kalis fish processing plant".

A spokesperson for the Department of Primary Industries and Regional development, which manages Sharksmart, said great white sharks are known to travel over large ranges, including Exmouth.

The spokesperson added that there is "no scientific information available to suggest that white sharks have been more prevalent in that area in recent years".

They urged that any shark activity be reported to Water Police.

Professor Meeuwig has been studying the impacts of climate change on marine life, and said the Exmouth sighting defied expectations.

"The big issue around climate change is that most species are moving south, because it's getting too hot," she said.

She said not enough was known about the "secret lives of ocean wildlife" and more research was needed to understand the "enigmatic" species.

"We don't know enough about how white sharks move," she said.

The shark sighting comes just a week after a crocodile sighting in the Exmouth region caused a stir among locals.

There have also been reports of a crocodile sighting at Eagle Bluff in Shark Bay, which resulted in the closure of a 24-kilometre stretch of beach while authorities investigated.

The Department of Biodiversity, Conservation and Attractions (DBCA) said it was still unable to confirm the validity of the image.

Shark Bay Shire President Cheryl Cowell said a crocodile hadn't been spotted in the area in more than 20 years. 

"It can happen, but it's highly unusual to be in that temperature of water for a saltie," she said.

Other animal sightings go viral

Further north, a Port Hedland man captured video of a pod of around six to eight orcas, playfully circling his boat.

Senior mammalogist Rebecca Wellard said the orca pod was a less unusual sight in the north-west, because their patterns are food-driven. 

"One of their main primary feeds is humpback whale calves, so they don't follow a traditional migratory pattern," she said. 

"They have a time frame between March to November where we can see them anywhere from the Abrolhos Islands up to Broome, which is such a big space." 

Ms Wellard urged citizen scientists to continue to report sightings along WA's coast.