Summer brings fresh bull shark threats
Wednesday, September 15, 2010, 1:00 pm
Photos: Dave Irving. Source: Flickr
University of Queensland zoology professor Craig Franklin says increasing human activity in our waterways can lead to more encounters between swimmers and bull sharks.
Recent sightings of bull sharks in south-east Queensland waterways are once again causing concern.
As the weather starts to warm up more people will be swimming at our beaches and cooling off in local rivers.
Unlike other sharks bull sharks have an ability to survive in salt and fresh water because they are able to retain salt in their bodies.
According to scientists the bull shark is considered one of the most dangerous sharks in the world as it swims in very shallow waters and is prone to attacking humans.
Over the years bull sharks have been blamed for many deaths in the Gold Coast canal systems and the threat was highlighted in 2006 with a brutal mauling of a teenage girl at North Stradbroke Island.
Professor Franklin is quick to defend the aggressive, unpredictable species saying it is wonderful to have these animals in our waterways as they play a critical role in our ecosystems.
“We have to learn to live alongside these remarkable animals,” he said.
“All we have to do is modify our behaviour and be careful where we swim and the time at which we swim.”
Brisbane angler and founder of the website brisbanefishing.com.au Angus Gorrie says it is a risk anywhere you go swimming where there are sharks.
“The Brisbane River is a much more vibrant ecosystem than people realise,” he said.
“It’s a very common occurrence to catch bull sharks in the river as there is an abundance of food for them like catfish and mullet.”
Mr Gorrie has sound advice for swimmers in this coming swimming season.
“It’s a cliché but don’t go swimming at dawn or dusk and especially if the water is really murky because if the visibility is low then they’ll [bull sharks] will take a swipe at anything,” he said.
Fisheries Queensland Shark Control Program manager Tony Ham says bull sharks have a reputation for being exceedingly aggressive.
Mr Ham echoes the advice to avoid swimming in murky and unsettled water conditions.
“Sharks are highly active in these conditions and swimmers should consider this before taking to the water,” he said.
The Shark Control Program aims to prevent the threat of shark attacks on humans.
The program uses drumlines and nets in specific locations ranging from Cairns to the Gold Coast. It is not designed to provide a distinct barrier between humans and sharks but to minimise the risk.
Safety Tips for Swimmers
The following tips are useful for swimmers to maximise safety in the water.
- Swim or surf only at patrolled beaches; between the flags and where shark safety equipment is in place.
- Obey the lifesavers’ and lifeguards’ advice, and heed all flags and noticeboard warnings.
- Do not swim or surf after dusk, at night, or before dawn when sharks become more active.
- Do not swim or surf in murky or silt-laden waters.
- Do not swim in, or at the mouth of, rivers, artificial canals and lakes.
These tips are recommended by the Queensland Government but ultimately it is the responsibility of individuals and carers to exercise good judgement and caution when choosing to enter the water.