The Greenland Shark is a prehistoric shark, it has an extra gill slit than the modern day shark, so it comes from another era. It lives thousands of feet on the bottom of the North Atlantic Ocean, so very few people know about it. The Greenland Shark is known to live up to 200 years old. Parasites latch onto the eye of the shark and feed off the tissue of the eye, rendering the shark blind. But they have no problem hunting for food, they have incredible smell and, like most sharks, they can sense the vibrations that prey give off.
Spent the morning cleaning up Perth City Beach for Word Oceans Day with UWA Guild Volunteering - the only event in WA that day! Couldn’t believe some of the rubbish we found- so many lolly sticks and straws! I’m definitely going to start rethinking my drinks and lolly choices.
If you skateboard you can die..
If you get stung by a bee you can die..
If you cross the street… Guess What…
This is in response to Australia’s idea of trying to catch and kill the sharks responsible for killing those unfortunate people last week.
There are risks in everything humans do. People that go in the water have to know and accept the risks they take in anything they do. That is no reason to go kill an apex predator that is in it’s own environment. If someone got stung and killed by a jellyfish are people going to go kill all the jellyfish in the water? No because these are just things in nature that humans might face in their life and living the lifestyle that they choose.
Lauren DeStefano’s viral tweet nails why we all need to stop thinking about and framing rapist Brock Turner as a star athlete or student gone awry. DeStefano also had some brutal truths for Turner’s father.
Weddell Seals are the most southern-dwelling of all mammals, with the exception of humans. They spend most of their time in the water, but are often seen on sea ice. Their teeth are strong enough to chew through ice to make breathing holes.
Weddell Seals can be different colors, including gray and brown, and often they have spots on their coats. They are one of the biggest seals, weighing 850-1000 lbs. The males are slightly smaller than the females. Weddell seals hunt in the water, for fish and crustaceans mostly. The sounds they make underwater can be heard from 20 miles away!
Sharks range in size from the largest fish on the planet to the length of your palm. See how you compare to some of these vulnerable predators that are so crucial to the ocean's health.
Are disproportionate fears driving shark culls? After the release of a trailer for yet another inaccurate killer shark movie (The Shallows) and the murder of a great white shark in Western Australia that may or may not have been the one that bit off a surfer’s leg, I feel like now is the right time to share this article I wrote on who should really be scared of whom in the ocean. For example, did you realise that last year, there were more selfie-related deaths than those linked to shark attacks?
Click below for a blog post adapted from a feature article I wrote in which I explorin the threats to shark populations, and why we should care if they disappear.
Last year, a rather morbid record was broken: most shark attacks in a year, with 98 unprovoked attacks. Coincidentally, 2015 also marked the 40th birthday of the genre-defining blockbuster ‘Jaws’. This was a film powerful enough to terrify its viewers out of ever swimming again, but is this fear of sharks well founded? Take the record-breaking rates from last year: 98 unprovoked attacks worldwide, six of which were fatal. Tragic as these statistics are, they somewhat pale when compared with those of selfie-related deaths, of which there were 12 last year. If sharks are simply “mindless eating machines”, what does that make humans, who kill 73 million sharks each year for finning alone?
Who’s calling for culls?
Shark attack rates are on the rise and many people are calling for culls to deal with them. However, shark abundance is actually decreasing, so are culls really suitable, or even necessary? Most research blames the attack rates on the growing human population and associated changes in the use of the ocean. In other words, more people are in the water and so there are more opportunities for sharks and people to interact.
However, this is little comfort to bathers and surfers who need to feel safe if they are to be tempted to spend time and money on tourist-hungry coasts. This has led to the implementation of various shark culls. In 2014, 68 sharks were killed in a trial catch-and-kill scheme in Perth, Western Australia. The following year, however, the scheme was discontinued, primarily due to a report which questioned the scheme’s efficacy and found it would have a greater negative impact on non-target species, including those important to the tourist industry such as dolphins and sea turtles.
The trial was also protested by many scientists who argued that there is no evidence that the cull would reduce shark attacks. “In Hawaii they spent 16 years killing tiger sharks through a hook and line program” said Professor Jessica Meeuwig, a marine biologist who co-ordinated a submission to the Environmental Protection Authority (EPA) opposing the cull “And it had no impact on the number of incidents with sharks”.
However, the scrapping of the WA cull did not please everyone. The WA premier was disappointed with the decision and still fears for public safety. “I cannot say that the South West has the degree of safety that Perth beaches do have” said Colin Barnett, “that’s the real issue we’ve got to face now”. This concern is due to the known habit of sharks to spend longer in the south west. A separate review had recommended the trial continue for three more summers as it was “likely” to be successful, but irregular attacks hadn’t generated enough data to assess the scheme’s effectiveness.
Why are sharks in danger?
As well as endangering non-target species, shark culls can be viewed as introducing yet more stress on shark populations already under risk of collapse. One of the biggest threats is overfishing. Targeted fishing for finning, despite being banned in many countries, kills 73 million sharks annually and continues to expand due to its cultural significance in China and Hawaii.
Bycatch (non-target species which are accidentally caught with the target fish) is also a major consern.50 million sharks are caught as bycatch every year through longlines, bottom trawlers and gillnets. Longline fishing, widely used to harvest species such as tuna and swordfish⁸, is the main culprit as sharks eat the bait or the fish that are attracted to the bait. Paradoxically, longlines are also invaluable in shark conservation as bycatch rates are used to estimate shark abundance in the area. For most open water and coastal species, this is the only reliable data source.
These problems are further exacerbated by sharks’ slow growth rate, meaning they take a long time to mature and reproduce in order to rebuild their numbers. Therefore, overfishing has had a very clear impact on reef and open water shark populations. One study found that white, thresher and scalloped hammerhead shark populations had decreased by more than 75% over 15 years.
Photo credit: Paul Hilton
Why is this so worrying?
The collapse of shark populations will have far reaching and long lasting implications. Their position as apex predators gives them strong control over the populations of species lower in the food web, meaning they are key to maintaining balance in open water and coral reef ecosystems.
“Sharks...play a key role in maintaining healthy reef ecosystems”
The dangers of losing sharks can be illustrated in some coral reefs in the Caribbean. “Sharks are strongly interacting apex predators and play a key role in maintaining healthy reef ecosystems” as written by Robins, et al. in their paper on reef shark population collapse. In fact, overfishing of reef sharks has already led to the degradation some Caribbean coral-reef systems through initiating trophic cascades. This is an effect whereby the removal of a top level predator leads to increased numbers of their prey, which in turn consume more, and so results in a dramatic decrease in resources within the ecosystem. In the Caribbean, overfishing of sharks has led to an increase in herbivorous fish, resulting in a shift from coral- to algal- dominated reefs. Algae is a much faster grower than corals, and so quickly fills space left by consumed coral.
Hope for the future
So what hope is there? Marine reserves are a favourite method for marine conservation, as they create ‘safe havens’ where fishing is prohibited so species abundance can regrow. However, these are coming under more criticism as studies show marine reserves simply shift the problem by displacing overfishing to other areas. The latest research suggests these management plans can only succeed if they are accompanied by controls to reduce overall fishing.
Research is also leading to innovative new ways to protect the public, that may eventually render shark culls and nets (which can also kill sharks and other animals through entanglement) obsolete. One device showing promise is the ‘shark-safe barrier’, that uses artificial kelp and magnets as visual and electro-sensory cues to deter white sharks. A study conducted in South Africa found that the barrier successfully altered shark swimming behavior and had no noticeable effect on cape fur seals, proving it an effective and shark-specific barrier. Progress has also been made designing wetsuits with high contrast patterns to make surfers appear less appealing as a food source.
Social media has certainly proven itself a valuable tool in fighting the Jaws legacy, with many scientists and young activists alike speaking out against shark culls, and working together to dispel the myth of sharks as ‘mindless eating machines’. If this momentum continues, we may soon see a complete paradigm shift in the public’s perception of sharks, which is key to their protection.
References
MovieClips Trailer Vault (2011, Dec12) Jaws Official Trailer #1 - Richard Dreyfuss, Steven Spielberg Movie (1975) HD [Video File]
Bascompte, J., Melian, C., & Sala, E. (2005). Interaction strength combinations and the overfishing of a marine food web. Proceedings Of The National Academy Of Sciences, 102(15), 5443-5447. http://dx.doi.org/10.1073/pnas.0501562102
Baum, J. (2003). Collapse and Conservation of Shark Populations in the Northwest Atlantic. Science,299(5605), 389-392. http://dx.doi.org/10.1126/science.1079777
Baum, J. & Blanchard, W. (2010). Inferring shark population trends from generalized linear mixed models of pelagic longline catch and effort data. Fisheries Research, 102(3), 229-239. http://dx.doi.org/10.1016/j.fishres.2009.11.006
Curran-Ragan, S. (2016). Triadic sensory approach suggested to deter shark attacks. Sciencewa.net.au. Retrieved 7 May 2016, from http://www.sciencewa.net.au/topics/fisheries-a-water/item/1444-triadic-sensory-approach-suggested-to-deter-shark-attacks
Dell’Apa, A., Chad Smith, M., & Kaneshiro-Pineiro, M. (2014). The Influence of Culture on the International Management of Shark Finning. Environmental Management, 54(2), 151-161. http://dx.doi.org/10.1007/s00267-014-0291-1
McPhee, D. (2012). Likely effectiveness of netting or other capture programs as a shark hazard mitigation strategy in Western Australia. Department of Fisheries, Perth, Western Australia. Retrieved from http://www.fish.wa.gov.au/Documents/occasional_publications/fop108.pdf
O’Connell, C., Andreotti, S., Rutzen, M., Meÿer, M., Matthee, C., & He, P. (2014). Effects of the Sharksafe barrier on white shark (Carcharodon carcharias) behavior and its implications for future conservation technologies. Journal Of Experimental Marine Biology And Ecology, 460, 37-46. http://dx.doi.org/10.1016/j.jembe.2014.06.004
Shark Savers :: What is Bycatch?. (2016). Sharksavers.org. Retrieved 7 May 2016, from http://www.sharksavers.org/en/education/sharks-are-in-trouble/what-is-bycatching/
Sharkproject. (2016). Sharkproject.org. Retrieved 7 May 2016, from http://www.sharkproject.org/haiothek/index_e.php?site=gefahr_10
Sturmer, J. (2014). World's top marine biologists, scientists call for end to Western Australia's controversial shark cull. ABC. Retrieved from http://www.abc.net.au/news/2014-07-04/hundreds-of-scientists-call-for-end-to-wa-shark-cull/5570366
West, J. (2011). Changing patterns of shark attacks in Australian waters. Mar. Freshwater Res., 62(6), 744. http://dx.doi.org/10.1071/mf10181
Image References:
Great White Shark, South Africa [Image]. Retrieved from https://www.flickr.com/photos/doobybrain/475576450/in/photostream/
Paul Hilton (2011). A shark is caught in a fishing net in Indonesia [Image]. Retrieved from http://www.npr.org/sections/pictureshow/2011/10/21/141587542/photos-show-sheer-scale-of-shark-fin-trade
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