Sydney Harbour scientists tracking bull sharks
BULL sharks are due to start arriving in Sydney Harbour next month and scientists are urging people to be smart about time spent in the water. Researcher Dr Amy Smoothey shares what it is like to catch and tag these massive creatures.
Mosman
Don't miss out on the headlines from Mosman. Followed categories will be added to My News.
ADRENALINE is pumping when the bull shark is pulled to the edge of the boat. Caught in lines set on the sea bed, the huge animal is roped by the tail and rolled on its back.
Scientists move quickly to make a small incision in its abdomen and insert a tag, which will allow it to be tracked for 10 years along the Australian coastline. After nose to tail measurements, the hook is removed and the shark is set free to roam again in the waters of Sydney Harbour.
“It’s a bit surreal,” researcher Dr Amy Smoothey said of the moment the huge sharks are floating alongside her boat.
“These are not small sharks. These are large animals.”
Having a shark so close to the researchers sounds more dangerous than it actually is. Once the animal is on its back it is in a state of tonic immobility and this allows Dr Smoothey and the team to do their research without any nasty consequences. The encounters last just 15 minutes.
“It’s quite astounding they swim around in the harbour here,” her colleague Dr Vic Peddemors said.
“We have all grown up being scared of bull sharks. This is supposedly one of the most dangerous sharks.
“Sydney Harbour has hundreds of people swimming in it every day and yet, touch wood, we almost never have an incident.
“It shows these animals are swimming out there but they are not really interested in people at all.”
The researchers are based at the Sydney Institute of Marine Science at Chowder Bay and are part of the NSW Department of Primary Industries. The DPI launched the Sydney Harbour bull shark tagging program after navy diver Paul de Gelder was attacked off Wooloomooloo in 2009.
Prior to its foundation, very little was known about shark movements in the harbour or what the feared creatures were actually doing there. So far the researchers have tagged 66 large bull sharks, with the largest at 3.2m, and they have found interesting information about their patterns.
“Sharks are arriving in the harbour around late November,” Dr Smoothey said.
“They come all the way from the Great Barrier Reef and stay in the harbour throughout the summer and autumn months. The bull sharks in Sydney Harbour are quite majestic. They are a largely misunderstood animal.”
Dr Smoothey and Dr Peddemors encourage people to sensibly make use of the harbour. The sharks swim through every corner of the waterway including Middle Harbour and both the Lane Cove and Paramatta Rivers.
They advise people to be shark smart and avoid the water at dawn, dusk and after heavy rainfall.
Dr Smoothey and Dr Peddemors are delivering a talk called The Secret Lives of Sydney’s Sharks Revealed at the SIMS Emerald Dinner on October 18 in Sergeants Mess. Tickets are available at sims.org.au