Tag Archives: shark nets

The High Price of Peace of Mind

We Aussies love our beaches – in the warmer months the coastline has a magnetic pull, drawing us to the sand, sea and surf in our thousands.

But while the thought of a refreshing ocean dip might be appealing, the concept of potentially coming face to face with one of our most feared predators has prompted officials to take drastic action.

Shark nets have been deployed off the shoreline of the east coast for more than 80 years.  But they offer a false sense of security.  Stretching less than 200 metres long and extending down only 6 metres, these mesh barriers are at best a deterrent and certainly don’t make beaches attack proof.

Sharks can get under, over or around them, and as it turns out, more are caught on the shore side of the net when they’re heading back out to sea, than when they’re swimming towards shore.

The holes in the mesh are around 50 centimetres across – large enough to let small animals pass through, but the perfect size for trapping bigger species.

Turtles, dolphins and rays are common victims of the nets – becoming entangled and drowning or starving to death.  A major concern is the ensnaring of humpback whales on their journey back to Antarctica after their annual breeding season in the tropics.

Calves in particular are easy prey – in just over a decade 55 have been caught in the shark nets, including one off Noosa in late September this year.  Another swam down to Sydney with the remnants of a Queensland net still wrapped around its mouth.

But the toll on the animals targeted by these barriers is far greater. In 2017 alone, more than 500 sharks were caught in the nets off Queensland – 377 died, more than 100 others had to be euthanised – only 20 were released.

Amongst the victims were grey nurse sharks which are classified as critically endangered and pose no real threat to us.  The vast majority of species share the sea quite peacefully with people – only a handful of sharks are responsible for fatal attacks on humans.

Just to put it all into perspective, on average one person a year is killed by a shark in Australia, as opposed to 5 dying from falling out of bed, 10 struck down by lightning or perhaps the most sobering, more than 1,100 taken on our roads.

Shark attacks are extremely rare and there is no scientific evidence to prove that nets protect humans.  What we do know is the attempt to keep us safe is killing marine life indiscriminately.

Removing so many animals, including apex predators, will have an impact on  local marine ecosystems – but we won’t be able to calculate that cost until far too late.

Marine biologist, Holly Richmond, feels so passionately about the need to remove all nets, she’s created a video:  www.thesharknetfilm.com

Ocean Life Education is passionate about protecting all marine animals and focusing on the important role sharks play in our oceans.  For more information about our programs including our Shark Discovery presentation visit: https://www.oceanlifeeducation.com.au/programs/

 

Shark nets, clever buoy, and protecting our beaches

Source: www.nsw.gov.au

Source: www.nsw.gov.au

Sharks, shark attacks and shark nets. You’ve probably heard the conversation in the media in recent times as our nation figures out a solution to ‘protect ourselves’ from a shark encounter.

In response to a number of shark confrontations along the NSW northern beaches (including popular spots Byron Bay and Ballina) the NSW government has carried out a comprehensive review on deterrent and detection methods to improve swimmer and surfer safety.

Ocean Life Education has long now been an advocate of education for public safety in and around our waterways. What we aim to achieve in our programs like our Shark Discovery, is a deeper understanding of sharks; the safest time and places to swim and why we sometimes come into contact with sharks.

As a long-time sceptic of the effectiveness of shark nets that are reported as protecting our popular beaches, I am delighted to see that the NSW government is reviewing both deterrent and detection methods for their northern beaches, which means that shark welfare is being considered as part of their review process.

The review mostly focuses on results of the effectiveness of such methods on the Great White, Tiger and Bull Whaler sharks and includes fourteen deterrent strategies and three detection strategies.

Review of deterrent methods

Of the deterrents, four involve electric and electromagnetic nets, ropes and cables; three are barrier nets (non-entanglement nets); five are various personal devices (worn by surfers or swimmers); a bubble curtain; and the Smart Bouy system (similar to a drum line but with capability to alert when a shark is caught so it can be quickly released).

The results showed the barrier nets were most effective, however the trials for these nets were carried out in Western Australia at a relatively protected beach where wave heights never exceeded 1.5m, therefore not a great indicator for open East Australian beaches that can have six-plus meter waves.  Not only that but keeping the barriers clean of fouling was another concern.

The electronic devices were problematic to other animals’ sensory abilities and also problematic to humans with heart problems who may use pacemakers. Personal devices varied in effectiveness but deemed not practical to protect great numbers of people at large beach sites. While the bubble curtain is an unobtrusive idea to humans and animals alike it wasn’t highly effective at deterring sharks.

Finally, there was the Smart Buoy which is just a baited drum line, with ability to alert it’s managers of a hook up, allowing the shark to be relocated. The problem here is using a baited hook brings sharks in and catches them, but also dolphins and turtles get caught too, plus staff managing relocation of animals need the right equipment and training to relocate effectively.

Review of detection methods

There were three detection methods trailed: shark spotter program; clever buoy; and tagging and real time tracking of tagged sharks.

The shark spotter program proved the most effective method of detection, the only problem is the shear expanse of coast line that needs to be monitored along the NSW north coast, which would incur a large expense.

Tagging and tracking sharks has been used by scientists for a long time now, it is effective in tracking sharks’ movements but not practical in being able to tag all sharks. Thus, this strategy rated low on the review.

Of great interest was research into technology such as the ‘Clever Buoy’, a collection of detector buoys, using sonar technology to detect large moving objects, which then sends a signal to a shore base to advise swimmers (for example a life guard tower). This detector method would keep swimmers safe and prevent the death of any marine life. It’s a win-win situation in my books.

Watch the video by Optus about how the Clever Buoy technology works.

The review did mention that this was in trial phase and needed tweaking, but with increasing technology improvements, this kind of protection for beaches is three to five years away and is both a good result for swimmers and the environment.

Final word

In 2017 we can say keep an eye on the future, it looks bright. It is great to see an improved environmental approach to an ongoing problem of humans living in harmony with the marine environment. If NSW adopts this technology and proves its effectiveness we hope that Queensland will follow suit.

Richard Coward, Director of Education

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