Visitors to a beach in the Royal National Park, north of Wollongong, have been told to steer clear of the water.
A dead whale floating close to Wattamolla beach has increased shark activity in the area, forcing the closure of the popular swimming spot amid safety fears.
An alert on the NSW National Parks and Wildlife Service (NPWS) website has urged visitors not to swim, snorkel or scuba dive at the beach “due to a decaying whale carcass and shark activity that is currently in the immediate area”.
Penalties apply, the NPWS has warned.
The dead whale spans about 18 metres. However, its species has not yet been determined.
“We’re working on that in association with the Australian Museum and scientists,” the NPWS’ Royal National Park manager, Shaun Elwood, told the Mercury.
“We have body tissue samples that are getting analysed to help with that identification. It’s not a humpback whale.”
Mr Elwood said the carcass could be that of a sei whale, but it was too early to say definitively.
“The comments are that once it is identified, the options or the potential species that have initially been raised as possibilities are all very rare in the sense that the recorded incidence or occurrence in NSW is very limited over the past 50 to 60 years,” he said.
How the whale died was also not known. Mr Elwood said it would be “very difficult” to determine the cause of death.
“It could have been an old whale, so it could have been a natural death, or it could have been a little sick for some reason. It also could have been struck by boat,” he said.
“It’s a very large whale .We’re talking an 18-metre long whale, which could potentially weigh between 30 and 40 tonnes.”
The carcass, which was first reported to authorities on Monday, had been wedged on rocks for a number of days. It has now come free and NPWS staff are monitoring the situation.
Mr Elwood urged visitors to the beach not to swim in the area and to use common sense.
“Unfortunately, we’ve seen quite a few instances in the past few days where common sense has not prevailed,” he said.
“Even the advice of ourselves, the police or Roads and Maritime haven’t been followed either.”
Boats have also come in close proximity to the carcass in recent days. Water police and Roads and Maritime Service staff have been in the area, in an attempt to keep vessels away.
If the carcass washes ashore and becomes stranded on the beach, Mr Elwood urged people not to touch the animal – for health reasons and due to legal restrictions.
The dead whale is the second spotted at national parks south of Sydney.
Earlier this week, a juvenile humpback whale – first seen entangled off Sydney – washed up dead on the Far South Coast.
The whale was discovered on Long Beach – at the northern end of the Ben Boyd National Park, near Pambula – on Monday.
For further information about the Wattamolla whale carcass, call the NPWS’ Royal National Park Visitor Centre on 9542 0648.