The Beacon

Blog Tags: Australia

The Myth of the Rogue Shark

That man-eating shark from Jaws may be fictional, but that doesn’t stop people from believing that sharks are out to get us — even though it’s not true at all.

Chris Neff, a PhD candidate at the University of Sydney, gave this talk at TEDxSydney about his research on the politics of shark attacks. In it, he identifies the three main misconceptions when it comes to shark-human interactions:

1. Sharks do not “attack”.
2. Rogue sharks don’t exist.
3. People don’t always react negatively to sharks following a shark bite.

Stories of sharks biting humans are uncommon, but get a lot of media attention when they do happen and are often sensationalized. A recent increase in shark accidents in Sydney, Australia prompted calls for a massive culling of the shark population.

But the thing is, sharks aren’t attacking humans maliciously. As Neff says, “trying to govern ungovernable events distracts us from real shark bite prevention.” Instead of killing even more of these important predators, we should be restricting areas where humans can swim and dive and changing our own behavior to prevent future accidents.

Because when it comes to sharks, “we’re in the way, not on the menu.”


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Skin Cancer Appears in Australian Fish

The black spots on this coral trout are melanomas. © Michael Sweet/Newcastle University 

Strange lesions are showing up in coral trout in the Great Barrier Reef in Australia.

In a new paper in the journal PloS One researchers found that 15% of reef fish tested showed signs of melanomas. This is a high occurrence, given that many of the fish with this condition may have already been eaten by predators or perished due to the illness.

This is the first time skin cancer has been documented in a wild marine fish species, but in the laboratory another species exposed to high UV radiation showed similar lesions, and they lived greatly reduced life spans.

The authors note that the occurrence of the melanomas was likely due to increased UV radiation and the proximity of the fish to the hole in the ozone layer which occurs over portions of Australia and Antarctica. The people of Australia already suffer huge health risks from skin cancer, topping the world in the occurrence of this illness.

These results are concerning because coral trout are an important commercial fish species, and they may suffer population level impacts if these rates continue. One third of all coral reef fish are already threatened with extinction due to the impacts of climate change on coral reefs, their home. Added stresses such as skin cancer could be the nail in the coffin for some species.

It’s important to figure out if skin cancer is occurring in more fish in a larger area, and what the risks are globally for marine life from UV radiation. We obviously can’t put sun-block on every fish in the ocean, but we can limit emissions of ozone-depleting gases like chlorofluorocarbons (CFCs), a refrigerant, as well as greenhouse gases that drive climate change which was also recently shown to threaten the ozone layer.

We are all in this together, so for the sake of fish and people we need to protect our thin layer of atmosphere.


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Marine Monday: Olive Sea Snake

olive sea snake

An olive sea snake in Australia. [Image via Wikimedia Commons]

When you think of ocean animals, snakes are not usually the first thing to come to mind, but they live as comfortably underwater as they do on the ground. Today’s Marine Monday features one of these swimming snakes, the olive sea snake.

Olive sea snakes live in corals in the waters above Australia. Divers should be cautious around these olive-brown snakes, as they will swim right up to anything that catches their curiosity, and they will bite if they feel threatened. An olive sea snake bite is venomous and can be fatal.

But don't worry, beachgoers have little to fear from this snake. Olive sea snakes live and hunt within their own small territories in coral reefs and rarely enter open water.

One cool thing about olive sea snakes is that they have a nine-month gestation period and give birth to live young, just like us! But their babies come in litters of five and are the size of a human finger, plus they grow up to be venomous sea snakes, so the similarities end there.

Want to learn more about cool marine creatures? Check out Oceana’s marine encyclopedia.


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Hairy-chested ‘Hoff’ Crabs and Hybrid Sharks

hoff crabs

Piles of the newly discovered "Hoff" crabs. © NERC Chesso Consortium

Happy New Year! Hope all you ocean lovers out there had a relaxing holiday. And what better way to start off 2012 than with some fascinating new ocean discoveries?

First, scientists have identified the first-ever hybrid shark off the coast of Australia, a result of mating between the common blacktip shark and the Australian blacktip shark.  The discovery indicates that some shark species may respond to changing ocean conditions by interbreeding.

And more humorously, scientists in the UK have found a new yeti crab species on the Southern Ocean floor that they have dubbed "The Hoff" because of its hairy chest – a la David Hasselhoff.

The researchers found hundreds of the crabs lying in heaps around hydrothermal vents – as many as “600 individuals per square metre." “Baywatch” and crustacean fans alike are rejoicing, and Mr. Hasselhoff himself even tweeted about the discovery.

If you could have a marine animal named after you, what would it be?


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Marine Monday: Leafy Seadragon

leafy seadragon

A leafy seadragon. [Image via Wikimedia Commons]

Underwater masters of disguise, leafy seadragons take their name from their greenish coloring and their many appendages that look like seaweed.

They belong to a group of fish closely related to seahorses and are found exclusively along the southern coast of Australia. Like their more famous cousins, seadragons have armor-like exoskeletons, and fertilized eggs are tended by the male. But seadragons have longer snouts than seahorses and cannot use their tail to grasp onto their surroundings.

Leafy seadragons are weak swimmers, so they avoid predators by blending in with their surroundings. They also move with the waves just like seaweed, which makes them even more difficult to spot.

Scientists aren’t sure how well leafy seadragons are doing these days. Unlike seahorses, they are not sought after by the traditional Chinese medicine market. There are anecdotal reports of seadragons accidentally caught by fishermen, but no estimates of how many fish this affects.

The more pressing concern is habitat loss: seadragons live in only a small strip of Australian waters, and their habitat is being destroyed by sewage from nearby cities. On the other hand, local governments have enacted several protection measures, and leafy seadragons, which are an important ecotourism draw, are the official fish of South Australia.

Learn more about the leafy seadragon and other fascinating animals at Oceana’s marine encyclopedia.


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Thursday Trivia: Flatback Sea Turtles

flatback sea turtle

A flatback sea turtle. Image via Wikimedia Commons.

We’re down to the last sea turtle in our trivia series, and it’s the least understood species of all – the flatback.

Flatback sea turtles nest only in Australia, and as a result of their limited range they are are poorly understood and at serious risk. Fortunately, Australia is working hard to protect large portions of the flatback’s habitat.

In addition to their namesake flat shells, flatbacks can be recognized by their olive-grey tops and yellow bellies. These turtles are known to float on the surface of the ocean, sunning their shells, often with birds on their backs. Flatbacks eat primarily fish, mollusks, and sea squirts.

Flatback turtles are caught accidentally in fishing nets, and they made up the majority of turtle bycatch in the Northern Prawn Fishery until turtle excluder devices – i.e. escape hatches -- were introduced. Other threats to flatbacks include coastal pollution and habitat degradation.

Oceana’s sea turtle campaign focuses on preventing sea turtle bycatch, protecting habitat, and promoting legislation that keeps turtles safe. You can learn more about flatback sea turtles from Oceana’s marine wildlife encyclopedia.

If you can tweet us the name of every type of sea turtle, you could win a tote bag. That’s it for our sea turtle themed trivia! We’ll be back next week with more fun facts about other ocean animals. 


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New Dolphin Species Discovered

Exciting news for cetacean lovers: DNA testing has revealed that what scientists had thought was a small population of bottlenose dolphins is actually a distinct species – one of only a few species of dolphin that have been discovered since the late 1800s.

The new species has been named the Burrunan dolphin— “Burrunan” is the Aboriginal word for a large porpoise-like fish. The Burrunan dolphin has a stubbier nose and a more curved dorsal fin than the bottlenose dolphin.

There are about 150 of the dolphins swimming off the coast of Melbourne. Because their small population and proximity to urban and agricultural centers, the dolphins may be threatened by runoff that ends up in their habitat, as well as commercial fishing and boat traffic.

Check out this video of the Burrunan dolphins from The Canberra Times:


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Guest Post: Australia Floods Further Endanger Dugongs

© Patrick Louisy via cites.org

Guest blogger Jon Bowermaster is a writer and filmmaker. His most recent documentary is "SoLa, Louisiana Water Stories" and his most recent book is OCEANS, The Threats to the Sea and What You Can Do To Turn the Tide.

The worst flooding in 130 years has turned eastern Australia into a giant wading pond, killing dozens of people, wiping out crops and livestock, destroying tens of thousands of homes and shutting down hundreds of towns and cities.

At risk at the edge of Queensland’s shores is the nearly extinct dugong – the prehistoric marine mammal that looks part sea lion, part bulldog – that feeds off the sea grass that line the coast. Unfortunately the floodwaters are inundating those feeding grounds with sediment, topsoil, rubbish and all sorts of debris on top of toxic industrial and agricultural run-off.

Environmental officials are concerned that the floods will similarly destroy wetlands, coral reefs and marine parks along Australia’s coast. Fresh water kills coral reefs, though  it remains to be seen what the long-term effects will be from this particular flood.


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Fact of the Day: Box Jellyfish

Today’s FOTD involves a short story. 

A few years ago, I was stung by a jellyfish while taking my first surfing lesson in Australia. It hurt so much that I could hardly walk!  We kept a close watch on my breathing while I was rushed to a pharmacy to get ice and some truly magical anti-sting medication.  (Thank goodness for that stuff!) After looking at my swollen and scarred legs, my instructor guessed that though I never saw my attacker, it was likely a young box jellyfish.   


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Sea Lion vs. Octopus

National Geographic has captured incredible footage of a sea lion battling a large octopus in Australia (spoiler alert: the sea lion prevails.) To get the footage, the hungry sea lion was equipped with a GPS tracker and a crittercam.

The project, led by South Australian Research and Development Institute, is helping researchers learn more about where and how sea lions feed, which will ultimately help in protecting key habitat for the creatures. Plus, it's just a really cool video. Check it out:

 


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