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



AAP Image/Sea Shepherd Australia

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.




Read more:
Why we’re opposing Western Australia’s shark cull: scientists


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.




Read more:
FactFile: the facts on shark bites and shark numbers


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.




Read more:
Sharks: one in four habitats in remote open ocean threatened by longline fishing


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.The Conversation

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.

Penguins under threat from drowning in fishing nets



File 20171130 12029 4drhxl.jpg?ixlib=rb 1.1
Bycatch: penguins can easily drown in nets designed to ensnare fish.
NZ Ministry of Fisheries

Ursula Ellenberg, La Trobe University

Fishing nets pose a serious risk to the survival of penguin species, according to a new global review of the toll taken by “bycatch” from commercial fishing. Fourteen of the world’s 18 penguin species have been recorded as fishing bycatch.

Among the species under threat are Tasmania’s little penguins and New Zealand’s yellow-eyed penguins, as detailed in a review, published in the journal Endangered Species Research.

The review shows the level of bycatch is of greatest concern for three species: Humboldt and Magellanic penguins, both found in South America, and the endangered New Zealand yellow-eyed penguins.

On New Zealand’s South Island, yellow-eyed penguins are down to fewer than 250 nests. Previous population strongholds have declined by more than 75%. Conservative population models predict local extinction of yellow-eyed penguins by 2060, if not earlier.


Read more: Shrinking Antarctic glaciers could make Adélie penguins unlikely winners from climate change


Penguins are among the world’s most iconic and loved birds, despite the fact that many people never get to see one in the wild. Indeed, the opportunities to do so are diminishing, with ten of the 18 penguin species threatened with extinction. After albatrosses, penguins are the most threatened group of seabirds. And, like albatrosses, bycatch is thought to be a serious issue for some species.

On land, many penguins are now well protected, thanks to the efforts of conservation researchers, government agencies, community groups and tourism operators. Where many penguins were once vulnerable to attack from introduced predators, or to habitat loss from farming or development, today the biggest worry for many penguin chicks is how to get more food out of their parents.

Time to eat yet?

But below the waves it’s a different story. Over thousands of years, these keen-eyed seabirds have evolved to catch food in the depths, while avoiding natural predators such as seals and sharks. But they cannot see the superfine nylon fishing nets invented in the 1950s which fishers now set in penguin foraging areas.

Little penguins, whose scientific name Eudyptula minor literally means “good little diver”, typically forage in the upper 20 metres of the ocean, with each dive lasting about 90 seconds. The larger yellow-eyed penguin – Megadyptes antipodes, the “big diver of the south” – prefers to hunt on the seafloor some 80-90m down, holding their breath for 2-3 minutes before coming up for air. If they do not encounter a fishing net, that is.

Gillnets (also called set nets) in particular are very dangerous for penguins. These nets are set in a stationary position rather than being dragged through the water. They are designed to catch fish around their gills, but can just as easily snare a penguin around its neck.

If it gets tangled in a net, a penguin will panic and drown in minutes. In Tasmania, nets with more than 50 drowned little penguins have been found washed ashore. Other penguins are found on beaches with characteristic bruising from net entanglement around their necks.

Nets are deadly to little penguins.
Eric Woehler, Author provided

When a penguin is killed at sea, this has knock-on effects back at the nest. The chicks will die of hunger or fledge underweight, with little chance of surviving their first year at sea.

The breeding partner left behind will probably skip a breeding season; some penguins never find another partner after losing their mate. I have seen them calling plaintively from their nest, or even going down to the shore in the evening to look out to sea, before returning to their nest all alone.

Declining numbers

In New Zealand, the endangered yellow-eyed penguin is declining. Current population models predict their extinction on the New Zealand mainland by 2060, or potentially even earlier. Yellow-eyed penguins are facing many threats mostly because they are simply living too close to humans.

Whereas threats on land are reasonably well managed, threats at sea need urgent attention. Marine habitat degradation by industries that damage the seafloor will take decades to recover. Similarly, pressures from climate change will not have a quick enough fix to save yellow-eyed penguins from local extinction.

There is one thing, however, we can change immediately: the needless death of penguins in fishing nets. This will give already struggling penguin populations a bit of a breather and maybe even the resilience required to deal with the many threats they face in their daily fight for survival.


Read more: New behaviour leaves Antarctic penguins on the shelf


Judging by the number of penguins washed ashore with net injuries, many fishers simply discard penguins’ carcasses at sea rather than reporting bycatch or working towards solutions to mitigate it.

Do we really want penguins to drown for our treat of fish and chips? Less destructive fishing methods are available that do not cause penguin bycatch and the death of other protected species.

But these more selective fishing methods would require fishers to change gear, which costs money. Currently, there is very little legal or commercial incentive for fishers to do anything about penguin bycatch.

The ConversationBut there are a couple of things you can do. Please do not just buy any fish with your chips – ask which species it is and how it has been caught. You can use a sustainable seafood guide, such as New Zealand’s Best Fish Guide or Australia’s Sustainable Seafood Guide. That way you can help the penguins snag a safe fish supper of their own.

Ursula Ellenberg, Honorary Lecturer, La Trobe University

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