A badly decomposed whale carcass has washed up on a Bunbury beach, sparking fears of increased shark numbers in the area.

The 10m humpback whale carcass was spotted on Belvidere Beach, north of Bunbury, by Department of Biodiversity, Conservation and Attractions (DBCA) officers at 11am on Tuesday.

A DBCA spokeswoman Grace Milne said the cause of death for the whale was unknown but that officials used bulldozers to move the ocean giant.

“Because of the decomposition, explosives were not needed to dispose of the carcass,” Ms Milne said.

The beach has remained open, but the Department of Primary Industries and Regional Development (DPIRD) has warned the carcass may attract sharks.

DPIRD spokeswoman Jodie Thomson urged the public to visit the Shark Smart website for more information about shark sightings and public safety.

“A shark alert has been put out,” Ms Thomson said.

While there have been no fatal attacks in Western Australia since early January this year, there has been a spike in the number of shark sightings, according to the Shark Smart website.

The annual Autumn salmon migration along the South West coast has been known to attract large marine predators, such as sharks.

The salmon form large schools and travel along the south-west coast as far north as Perth. Sharks following this migration could be the cause of the spikes in sightings, experts say.

The public has been advised to stay informed of shark activity information by checking the SharkSmart website, downloading the SharkSmart WA app or following Surf Life Saving WA Twitter.

The Government of Western Australia Department of Fisheries has been contacted but did not respond in time for publication.