RAPID REACTION: Culling great white sharks in Western Australia – experts respond

Mon Oct 24, 2011

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Following recent shark attacks in Western Australia the state government is apparently considering a cull and has given the go-ahead for any great white sharks to be killed if they pose a threat to human life.


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Professor Shaun Collin is WA Premiers Research Fellow and Professor of Neuroecology in the School of Animal Biology and UWA Oceans Institute at the University of Western Australia

“The recent deaths attributed to the great white shark attacks in WA are most distressing and a terrible loss for the families of the victims. However, the culling of any species of sharks is not the solution. Not only will this be indiscriminate killing of a protected Australian species (under both the EPBC Act and state legislation), there is no way of being sure the sharks caught will be those responsible for the attacks. At present, there is no data to suggest that shark numbers are increasing off WA’s coastline and shark attacks in Australia have remained relatively constant over time, occurring at a rate of approximately one per year for the last 50 years. Sharks are apex predators and they play a critical role in the complex balance of oceanic ecosystems and their removal can have major impacts on other marine species. Education and surveillance are the best prevention of human fatalities off the WA coast until better repellent devices are developed. Non-lethal shark protection measures such as spotter planes and patrol boats should substantially improve the ability to identify large sharks and enable swimmers and divers to avoid them. Australia (and especially WA) has one of the highest levels of biodiversity in the world. Culling sharks will upset the important role these apex predators play. Our Neuroecology Laboratory at The University of Western Australia is currently working on various methods to repel sharks based on their battery of senses.”

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Dr Charlie Huveneers is a Shark Ecologist within the Marine Environment and Ecology Program at the South Australian Research and Development Institute (SARDI Aquatic Sciences) and lecturer in the School of Biological Sciences at Flinders University, Adelaide

“There is no scientific evidence to suggest that the short time period between the recent attacks is a reflection of an increased population size of white sharks. It could simply be related to the seasonal fluctuation of the number of white sharks within specific areas and that white sharks might naturally be more often occurring around the populated Western Australian coastline at this time of the year. Unfortunately, we currently have no reliable measure of the population size of white sharks. However, we do have some evidence of large variations in the number of white sharks from year to year within specific locations such as the Neptune Islands off South Australia. A below average number of white sharks one year does not necessarily mean that the white shark population is decreasing. Similarly, an above than average number of white sharks the following year does not necessarily mean that the white shark population has dramatically increased compared to the previous year. It is more likely dependent on the distribution of white sharks and the various and complex factors influencing the movements and migrations of these sharks.

Although shark attacks are tragic events and are often highly mediatised, they are still very rare events with a low probability of occurrence. White sharks are also known to undertake very large migrations between South Australia and Ningaloo Reef on the west coast and off Rockhampton on the east coast. As a result, the culling of a few specimens within one location is unlikely to significantly reduce a risk of shark attack which is already extremely low.

Around the world, several means of mitigating shark attacks have been put in place with variable level of success, but it is unlikely that one method can be considered the best way to reduce shark attacks. A combination of techniques selected depending on the characteristics of each location frequented by potentially dangerous sharks is likely to be the most efficient. For example, the City of Cape Town has put in place a Shark Spotter program in combination with research aimed to understand the movement patterns of white sharks around seal colonies and populated beaches. The efficiency of the Shark Spotter program relies on the topography of Cape Town with mountains in close proximity to the beaches allowing the spotters to be on a high vantage point and monitor for the dark silhouette of sharks on the sandy background.”

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