Warning after second sighting of shark in popular Sydney lagoon

A warning has been sent out after a shark was spotted in a flooded lagoon, just days after what appeared to be a huge fin was filmed in water.

A Sydney Council have sent out a warning after a shark was spotted swimming in a flooded lagoon, believed to be the second sighting at the popular spot in just a few days.

Warning signs have been put up around Narrabeen Lagoon on Sydney’s northern beaches after a member of the public reported seeing a shark in the water this morning.

One of the signs reads: “Shark sighted today. Enter water at your own risk”.

Northern Beaches Council CEO Ray Brownlee said the sighting occurred near the bridge at Pittwater Road.

“Our Beach Services Team is investigating and warning signs are being erected at key points around the lagoon as a precaution,” he said.

“We ask the community to be aware.”

Warning signs have been put up around the popular swimming spot. Picture: @theclahaven/Instagram

This sighting comes just days after another report of a shark lurking in the floodwater.

Footage emerged on social media during wild weather on Sunday showing what appeared to be a large dorsal fin poking out of the lagoon.

The user who uploaded the footage to Instagram is an Airbnb host at Narrabeen who captioned the video: “Great white spotted in Narrabeen Lagoon”.

The website Dorsal Watch, which lists shark sightings around the world, featured a report at 7.23pm from North Narrabeen of a “fin spotted from shore”.

“Lagoon was opened up to the ocean due to storm and flood warnings,” the report read.

Torrential rain saw the lagoon swell in size over the weekend with nearby residents forced to evacuate overnight on Sunday following warnings of significant flooding.

What appears to be a large dorsal fin at Narrabeen lagoon. Picture: Francine Gray/Instagram

Narrabeen lagoon empties after huge amounts of water flowed into it causing minor flooding. Picture: John Grainger

But the wet weather hasn’t stopped people swimming in the popular spot, with one group pictured making a homemade slip and slide into the lagoon.

A shark was last spotted in Narrabeen Lagoon in January 2007. On that occasion, two men said they saw a great white swimming out of the lagoon after earlier reports from a fisherman who said it pulled a duck under water.

Stephen Burleigh told The Sydney Morning Herald what he saw.

“There were half a dozen ducks in the water,” he said.

“I saw four of them moving very quickly to the side but the shark got one and dragged it under the water, five metres under.

“I was worried if there were any children in the water. I stepped back and said, ‘I’m not fishing here any more’.

“It’s school holidays and a lot of kids come here.”

A group set up a slip and slide into the flooded lagoon. Picture: Damian Shaw

A number of people had to be evacuated from the area due to flooding. Picture: Damian Shaw

The Bureau of Meteorology has warned more wet weather is in store for parts of NSW. issuing a severe thunderstorm warning late on Tuesday for parts of the Northern Rivers, mid north coast, north west slopes and plains and northern tablelands forecast districts.

The bureau warned of intense rainfall that may lead to flash flooding in these areas overnight.

A very high chance of showers is forecast for Sydney, with 6-25mm possible on Wednesday and 15-35mm possible on Thursday.

Sydney recorded its heaviest rain in three decades and was battered by gale-force winds, with emergency services on Tuesday left to clear fallen trees, remove debris and extract cars from floodwaters.

Tens of thousands of households in Sydney and the Central Coast were still without power on Tuesday night, with Ausgrid asking customers to prepare for outages into the weekend.

-With AAP