Shark nets and culls don’t necessarily make Australian beaches safer

George Roff, The University of Queensland and Christopher Brown, Griffith University

Most of the 24 million annual visitors to Queensland don’t notice the series of seemingly innocuous yellow buoys at many popular beaches. Beneath the waves lies a series of baited drumlines and mesh nets that aim to make Queensland beaches safe from the ominous threat of sharks.

Earlier this week the Queensland government lost a legal challenge in the Federal Court to continue its shark culling program in protected areas of the Great Barrier Reef, and Fisheries Minister Mark Furner has written to the federal government to request legal changes to keep the program operating.

Since the Queensland Shark Control Program began in 1962, more than 50,000 sharks have been removed from Queensland beaches at a cost of some A$3 million per year.

While proponents of the program argue the absence of human deaths at beaches with shark control gear is proof of the program’s success, leading shark experts are not so sure.

Can shark control programs control sharks?

Large sharks roam across very large swathes of the ocean.
Photo courtesy of Juan Oliphant, Author provided

Through a series of baited drumlines and mesh nets, shark control programs aim to reduce local populations of large sharks, thereby reducing the number of times humans and shark meet along our coastline.

This approach assumes that the risk of shark bites directly correlates with the number of sharks, yet evidence for this is surprisingly lacking. As part of its safety at the beach program, the Queensland government states that:

Scientists believe that resident sharks may learn that nets and drumlines placed in their local areas represent an obstacle and actively avoid them. This in itself deters and reduces the local population of large sharks in that particular area.

There are two problems with this logic. First, large apex sharks are not local to individual beaches – satellite tracking data indicates they are highly mobile, moving thousands of kilometres across coasts, reefs and open oceans every year. Sharks tagged in the Whitsundays and Cairns have travelled thousands of kilometres throughout the Great Barrier Reef and beyond.

Second, there’s no clear evidence that sharks avoid drumlines. In fact, baited drumlines and nets actively attract, not deter, large sharks. Similar programs in Hawaii were stopped after an expert review concluded their effectiveness had been overstated.

Do shark control programs make our beaches safer?

Nets do not place an impenetrable barrier between swimmers and sharks. It is true only one death has occurred at beaches with nets and drumlines, but over the same period there were 26 unprovoked non-fatal incidents.

While a reduction in fatalities is often attributed to the success of the shark control program, it could also be that reduced response times and better medical interventions are more successful at saving lives in recent decades.

Culls, nets and baited drumlines are a blunt tool, unable to completely remove the threat of people and sharks meeting on our beaches. Advances in technology and improved education of swimmers may be a more effective way to create safer beaches in Queensland with less ecological cost.

Smart technology

Modern technology allows us to help people avoid sharks, by modifying our behaviour at beaches. Shark-detecting drones are being trialled on New South Wales beaches as part of that state’s A$16 million shark management strategy, allowing for real-time monitoring of popular coastal areas.

Technology like drones and smart buoys are increasingly good at spotting sharks.
Matt Pritchard/Wikimedia Commons

Underwater “clever buoys” installed at NSW beaches in place of baited drumlines allow for real-time detection of sharks using sonar technology, instantly notifying lifeguards of the location, size and direction of sharks. Solar-powered, beach-based shark warning systems operate on remote beaches in Western Australia, cutting the response time between shark sightings and authorities alerting beachgoers from nearly an hour to a matter of minutes.

Education about shark behaviour can also help. Sharks are more active in certain places, like river mouths, and at certain times, such as at dawn and dusk.

In fact, the Queensland government is prioritising research into shark and human behaviours. This research could support education that mitigates the risk of shark interactions, without causing ecological harm.

Earlier this year the Queensland government committed to a A$1 million annual funding boost towards trialling alternative technologies. Adoption of modern innovations and better education for the general public would improve beach safety while avoiding the expensive and ineffective methods of culls, baited drumlines, and nets.

The cost of shark control programs

While we will never have an exact idea of how many sharks used to roam the eastern coastline, historical estimates from shark control programs suggest that the number of large sharks has declined by 72-97% in Queensland and by as much as 82% in NSW since the middle of the 20th century.

Shark nets, culls and baitlines are expensive and ineffective.
Nicole McLachlan, Author provided

NSW and Queensland shark control programs combined have removed more than 1,445 white sharks from the eastern Australian coastline since the middle of the 20th century. To put this in context, current estimates indicate that the eastern population of white sharks sits at around 5,460 individuals in total.

The idea that sharks numbers have boomed in recent years represents a classic example of shifting baseline syndrome. The number of sharks on our beaches may seem to have grown since the late 1990s, but it is a fraction compared with a 1960s baseline, and long-term trends indicate that declines are ongoing.

The number-one priority at our beaches is keeping swimmers safe. At the same time, we have a responsibility to protect threatened and endangered species. There are smarter ways to manage both humans and sharks that will make our beaches safer and help protect sharks.

George Roff, Postdoctoral Research Fellow, The University of Queensland and Christopher Brown, Senior Lecturer, School of Environment and Science, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Shark tourism can change your mind about these much-maligned predators

File 20180906 190642 cnvjcy.jpg?ixlib=rb 1.1 — Getting up close and personal can make you like sharks more, even if you already like them.
Juan Oliphant, Author provided

Michele Barnes, James Cook University and Sarah Ruth Sutcliffe, James Cook University

Shark ecotourism can change people’s attitudes about sharks and make them more likely to support conservation projects – even after allowing for the fact that ecotourists are more likely to be environmentally minded in the first place.

In our research, published in the journal Marine Policy, we surveyed 547 participants in a shark ecotourism program oriented towards education and conservation off the coast of Oahu, Hawaii.

We looked at participants’ knowledge of and attitudes towards sharks, and their intention to engage with shark conservation projects before and after the tour. We then compared these with the knowledge, attitudes, and conservation intentions of 488 members of the public who had not taken part in shark ecotourism.

Even before taking part in the shark ecotourism program, participants were generally more environmentally minded, more knowledgeable about sharks, and had more positive attitudes towards sharks than the general public.

For example, 71% of participants had positive attitudes towards sharks before the tour, compared with only 45% of the general public. To a certain extent, therefore, the shark ecotourism program was attracting people who were already “converted” to environmentalism.

But, crucially, we also found that after the ecotourism program, participants had significantly more knowledge of the ecological role of sharks and a more favourable attitude towards them. There was a 39% increase in knowledge along our measured scale, and 97% of participants who held negative attitudes ended up changing their mind about sharks as a result of the tour.

Ultimately, the program had a significantly positive effect on people’s intentions to engage in shark conservation behaviour, despite them already being more environmentally minded than the general public. In other words, these programs are not just “preaching to the converted” – they really do improve people’s engagement with conservation.

Learning to love sharks?
Juan Oliphant, Author provided

Sharks’ PR problem

Sharks are crucial to our marine ecosystems, yet many shark populations are in decline as a result of fishing (particularly for shark fin soup), fisheries bycatch, habitat destruction, and climate change.

To survive, sharks need a coordinated global conservation effort. And for that they need people to speak up for them.

Unfortunately, sharks have a PR problem. They are feared by many members of the public, demonised by the media, treated as human-hunting monsters, and cast as the villains in blockbuster movies like Jaws and The Meg. In many places, government-funded programs actively cull sharks in the name of beachgoers’ safety.

Winning hearts and minds

Shark ecotourism provides an opportunity to learn about sharks’ role in ocean ecosystems, and to view and interact with them in their natural environment. Our research suggests it offers a way to counteract misconceptions and build support for shark conservation.

Not all programs marketed as shark ecotourism are equal, however. There are legitimate concerns about some forms of shark tourism, with important questions about animal welfare, ecological impacts, and public safety (particularly where chum or bait is used to attract sharks).

The conservation benefits of shark ecotourism are thus most likely to be realised when it is conducted responsibly, with trained staff, in areas that don’t conflict with other ocean uses.

Hopefully, our findings will encourage the development of responsible, environmentally friendly and educational shark ecotourism programs with specific conservation goals, which will allow people to engage with sharks in a positive way. In turn, that could help to build political and social pressure to conserve sharks.

Michele Barnes, Environmental Social Science Research Fellow, James Cook University and Sarah Ruth Sutcliffe, Marine Social Sciences PhD candidate, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

FactFile: the facts on shark bites and shark numbers

File 20180226 140181 un3yf6.jpg?ixlib=rb 1.1 — The CSIRO has provided new estimates of population sizes for White Sharks in Australian waters.
Fiona Ayerst/Shutterstock

Jane Williamson, Macquarie University and Vincent Raoult, University of Newcastle

Are there more sharks in Australian waters than there used to be, and are interactions between humans and shark increasing? Some Australian politicians have claimed that to be the case.

Let’s look at the research.

The most reputable source for shark incident data in Australia is the Australian Shark Attack file, which is collated at Sydney’s Taronga Zoo.

The map below, created by The Conversation using data from the Australian Shark Attack File, shows incidents between sharks and humans in Australia between 1997 and 2017.

You can use the filter buttons in the map to explore the data by year, season, the type of injury, the type of shark involved, the type of incident – or a combination of all the filters. Press the ‘show all’ button to reset the search.

https://cdn.theconversation.com/infographics/243/f87e27e72eb6545d5422e204b9894dedaad0f92f/site/index.html

The number of recorded encounters between sharks and humans in Australia increased modestly between 1997 and 2017, but the reason for this is unclear. Over those two decades, the Australian population increased by 33%, but that alone doesn’t explain the increase in recorded shark encounters.

Correcting for the growth in human population in Australia, the data show that between 1997 and 2017:

incidents resulting in injury increased by 1.59%
incidents without injury increased by 0.36%, and
fatalities increased by 0.07%.

Encounters between humans and sharks are extremely variable over time, and difficult to predict. The increases in recorded incidents between 1997 and 2017 are relatively small, and may be explained by factors not related to shark populations – such as increases in the reporting of shark encounters, or increasing beach use.

https://cdn.theconversation.com/infographics/159/62c30e6dedecffbbeb4e059c8ab0e573d756f61b/site/index.html

Are there more sharks off the Australian coast?

White Sharks (formerly Great White Sharks) are recorded as being responsible for 28 of the 36 fatal shark encounters in Australian waters between 1997 and 2017, and are the primary target of shark mitigation strategies of the Western Australian, New South Wales and Queensland governments.

So, has there been an increase in the number of White Sharks in Australian waters?

Estimating population numbers in the marine environment is difficult, especially for long-lived migratory species like White Sharks.

However, there is no evidence that White Sharks numbers are on the rise, either in Western Australia or along the Eastern coast. Despite targeted conservation efforts, the available research show stable or slightly declining numbers in these populations.

There are two distinct populations of White Sharks off Australian coasts – one to the west, and another to the east of Bass Strait, which separates Tasmania from mainland Australia. The eastern population includes New Zealand White Sharks.

Recent work by the CSIRO through the National Environmental Science Program’s Marine Biodiversity Hub using innovative DNA analysis has provided us with the most detailed and reliable estimates of population size we have for this species.

The CSIRO study shows there has been a slight decline in adult White Shark populations since the year 2000.

Current adult abundance for the eastern Australasian population is estimated at 750, with an uncertainty range of 470 to 1,030. The southern-western adult population is roughly double the size, estimated at 1,460, with an uncertainty range of 760 to 2,250.

Including the available information about juvenile White Sharks, estimates of total size for the eastern population in 2017 was 5,460, with an uncertainty range of 2,909 to 12,802.

It’s difficult to detect population trends with White Sharks because of the length of time it takes juveniles to reach maturity – around 15 years. As protection of White Sharks began in the late 1990s, any changes in abundance would only be starting to appear in current populations.

How else can we measure White Shark populations?

The traditional way of measuring shark and fish populations is by examining catches in commercial fisheries over long time periods. By correcting for the level of fishing effort – which is done by looking at things like the number of nets, hooks and tows deployed by fishermen – scientists can assume that changes in the “catchability” of sharks is related to their abundance.

But due to the relative rarity of catches of White Sharks by fishing vessels, this approach is less reliable for this species than the more recent genetic studies conducted by the CSIRO and outlined above.

Western Australia has a detailed measure of White Shark numbers assessed by catch data. A report published by the Western Australian Department of Fisheries in 2016 attempted to model changes in the southern-western Australian White Shark population since the late 1930s. The authors outlined four different plausible scenarios, none of which suggested a continuous increase in the number of White Sharks.

In New South Wales, there has been a cluster of shark bites in recent years. Data from the NSW Shark Meshing (Bather Protection) Program, managed by the NSW Department of Primary Industries, show a recent increase in White Sharks caught in nets placed near ocean beaches.

But when it comes to thinking about shark populations, we should not assume that these two facts are related. It’s important to remember that just because two things may correlate, it doesn’t mean that one caused the other.

These patterns could mean that the animals are coming closer to shore, rather than a population increase (or decrease).

https://datawrapper.dwcdn.net/Zzcem/2/

Shark and human interactions: what factors are at play?

A 2016 paper examined six global shark bite “hotspots” – the United States, South Africa, Australia, Brazil, Reunion Island and the Bahamas – and concluded that when it comes to encounters between sharks and humans, there are a range of causes at play.

These include:

rises in human population
habitat destruction/modification
changes in water quality
climate change
changing weather patterns, and
the distribution/abundance of prey.

The authors also noted that shark encounters appear to happen in clusters. For example, 2009 saw a spike in shark encounters off the New South Wales coast. This coincided with an increase in beach attendance and beach rescues during what was an unusually warm summer for south-east Australia.

A 2011 paper highlighted the popularity of water sports as a factor contributing to increased human-shark encounters. More people are taking part in water sports, and improvements in wetsuit technology mean that people are in the water for longer throughout the year.

However, there is limited information on the number of people who use Australian beaches, so this explanation needs to be further studied.

It’s vital that any strategies put in place to reduce the number of unprovoked encounters between humans and sharks in Australian waters are carefully considered, and based on the best available research.

Jane Williamson, Associate Professor in Marine Ecology, Macquarie University and Vincent Raoult, Postdoctoral fellow, University of Newcastle

This article was originally published on The Conversation. Read the original article.

Great White Shark

Seal Escapes Shark

Spectacular shark encounters: Fanning's close shave reminds us we share the ocean

Leah Gibbs, University of Wollongong

In the wake of the spectacular footage of champion surfer Mick Fanning’s recent shark encounter in Jeffreys Bay, South Africa, and his good fortune in emerging without physical injury, sharks are back on the radar.

Many people are probably scratching their heads wondering how we can avoid such dangerous incidents. Some have suggested that “shark attack” is on the rise, and therefore that risk is increasing.

But the risk of dangerous interaction with a shark is incredibly low. In fact, a recent study found that in California shark-related fatalities have decreased significantly since 1950.

Collecting statistics on shark incidents is more fraught than it might seem. The Global and Australian Shark Attack Files collect data on all reported interactions. But “risk” is fiendishly difficult to calculate because we don’t have good data on numbers of people using the ocean or types of activities people undertake.

Terminology adds to the confusion: “shark attack” is highly emotive and often misleading. More precise terms like “sighting”, “encounter” and “bite” do more to describe an interaction, develop public understanding of shark behaviour, and reduce the chance of reaction motivated by fear.

Learning from ocean-users

Our research recently published in the journal Marine Policy (and previously in Australian Geographer) focuses on the experiences and attitudes of the people most likely to encounter sharks; that is, ocean users.

We have talked with surfers, ocean swimmers, paddlers, divers, fishers, and others who use the ocean regularly for recreation, professional or volunteer purposes.

Two findings strike most:

Almost 70% of the 557 people surveyed have encountered or sighted a shark while undertaking ocean-based activities. This could be a shark of any species, and includes those listed in Australia as potentially threatening to humans, namely great white, tiger and bull sharks. The lesson here is that most of the time people and sharks co-exist without ill effect.
The most strongly supported strategies for managing risks associated with shark encounter are those that involve people adapting their behaviour. In particular, improving public education, and encouraging ocean users to understand and accept risks associated with entering the ocean. In contrast, the most strongly opposed strategies are those that involve killing sharks.

Efforts to manage shark-related hazards by killing sharks, through lethal strategies such as the baited drumlines rolled out in Western Australia last year and the shark nets currently under review in New South Wales, have been met with loud protest. The time seems ripe to reassess how we understand and manage our relationships with sharks.

Although frightening, the footage of Fanning at Jeffreys Bay is a reminder that sharks are present in the oceans, and that the vast majority of interactions between people and sharks end without fatality or injury.

Leah Gibbs is Senior Lecturer in Geography at University of Wollongong.

This article was originally published on The Conversation.
Read the original article.