Spike in shark sightings

A juvenile humpback whale carcass washed up near The Cut, large schools of bait fish and warmer ocean waters have been offered as possible explanations to Bunbury’s unusually high number of shark sightings.

Since the beginning of December more than 11 sharks have been sighted in Bunbury’s waters including sightings at Hungry Hollow, Koombana Bay and Dalyellup Beach.

Back Beach was closed on Boxing Day after a 4-5 metre shark was spotted by the South West Surf Lifesaving helicopter.

A young, deceased humpback whale washed up just north of The Cut a fortnight ago and was buried by the Department of Environment and Conservation.

A DEC spokesman said there were no visible signs such as bight marks from a predator on the 5.6-metre carcass.

The spokesman said the whale carcass could have attracted sharks but had not yet created a ‘‘slick’’.

Photographs of the whale’s body had been passed onto researchers from Murdoch University.

‘‘We buried the body as soon as it was reported and we would have put out a warning if we thought it could create a danger to the public,’’ the spokesman said.

The DEC said there had been several whale bodies wash up inWAbut it had expected a busy whale season because of the spike in the whale population.

This year’s unusually warm waters of the Leeuwin Current may have brought more big shark species to the South West as they follow migrating whales.

Recreational anglers have reported an influx of longnose grey whales this year which are often followed by the larger species of sharks.

Veteran Bunbury fisher Bruce Olsen said December was the prime time for hammerhead sharks which were chasing bait fish.

‘‘Hammerheads are easily identifiable with their very pointy fin, this is the time of year they skim along the surface as they feed and copulate,’’ Mr Olsen said.

Swimmers at Back Beach have also seen flocks of birds feasting on schools of whitebait not far from the shoreline. Keen beach-goer Fletcher Kylie said he had seen a big flock of seagulls diving for bait fish off Back Beach just before the helicopter spotted a shark on Boxing Day.