Culling shark realities

Why did it happen?

The species of concern in NSW are the great white, tiger, and bull sharks. Unlike great whites and tigers, bull sharks inhabit freshwater and coastal areas including rivers, harbours and estuaries. All species migrate seasonally with great whites preferring cool winter waters, while tigers and bulls are more common around Sydney in summer.

It’s important to remember that though extremely traumatic, shark bites remain incredibly rare – though some conditions increase the risk. In January, the extremely heavy rainfall led to runoff and murky water – reducing visibility. These conditions stimulate bull shark feeding behaviour and reduces their ability to visually identify. The combination of factors tragically led to greatly increased risk which saw 4 bites in 48 hours, including a fatality.  

Should we cull bull sharks?

Following these incidents, there have been calls from some in the community for shark culling for public safety. This will not work. Why not?

Firstly, bull sharks are already culled. NSW shares the population with QLD, as it ranges the entire east coast. The QLD Shark Control Program kills an average of 130 bulls a year, and thousands have been killed since the program began in 1962. NSW shark nets and NSW fishers, who are each allowed to kill one bull a day, add to that total. 

Secondly, shark culling does not reduce the risk of shark bite. Bull sharks are migratory. Culling for public safety assumes that a local population can be reduced through fishing. As bull sharks are constantly on the move, there’s no such thing as a “local population”. Additionally, culling actually attracts sharks. The culling methods only serve to attract sharks and stimulate feeding behaviour. Shark nets, baited drumlines, targeted fishing’s use of bait, these all add blood, viscera and animal carcasses to the water, attracting and exciting sharks, making the areas in which culling occurs far more dangerous.

Evidence

Humane World for Animals challenged shark culling in the Great Barrier Reef in court in 2019. The judges found:

Modern scientific consensus is that the risk of shark bite is not related to shark abundance but rather abundance of ocean users and other external factors such as anomalous weather events. We are convinced that shark culling does not reduce the risk of shark attack on the individual – the scientific evidence before us is overwhelming in this regard.

Further, from 1959-1976, Hawaii culled 4,668 sharks. No change in shark bite rate was found.

So, what can be done?

There is no silver bullet, but there are ways to reduce the risk of human-shark interactions:

1. Grow the drone program: The NSW Government has made a start, but greater coverage will always improve the ability to spot potential risks.
2. Equip the public with knowledge about conditions that increase/decrease risk, such as weather, time of day, and patrols and surveillance times.
3. Remove shark nets. Dead and dying wildlife in shark nets attract sharks. The last 3 incidents on the Northern Beaches occurred near shark nets.
4. Use of verified personal shark deterrents.

These things can be implemented to immediately improve safety. Culling bull sharks might make some people feel better, but it would be at best a placebo, and it may even be counterproductive. Do we want the community to feel safer, or do we want to reduce the risk?