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|Newsletter 11 | February 2018 | www.sharkcagediving.net ||
Why Great White Sharks Getting Smaller Should Scare You
I’d guess that if you told the average person that Great White Shark size was declining, they probably wouldn't be too upset. But in reality, this trend is incredibly dangerous for their populations and the ocean ecosystem as a whole. Though it seems like a simple concept, the idea of size is much more than just a number. Instead, it is a strong influence upon most every aspect of the organism, helping to determine how to adapt to fit its particular niche. In the case of Great White Sharks, its size is essential to its status as an apex predator of the oceans.
There is an subtle but noticeable decline in size. This pattern, if real, is cause for concern. Though a slightly lower size wouldn’t be a big deal on a functional level for an individual Great White Shark, on a population level, the decline in size indicates a shift in the percentage of sharks that are of reproductive age. Therefore, as the average size decreases, so do the number of sharks that can pup each year. As a species, these organisms are vulnerable as a result of their slow growth and whopping 15-year wait until maturity.
This graph also seems to indicate a slight increase in size from about 1960-1980. Though there’s not a complete explanation as to why this happened, it’s possible that the decrease in fishing during World War II may have given populations some time to recover, or perhaps this is just an effect of there being fewer sizing reports that this time.
Bottom line: It seems that Great White Sharks are now facing their greatest pressure in 16 million years – humans. After surviving this long in the delicately balanced ocean ecosystem, the decision is now in our hands as to whether to push these sharks into extinction, or create a system to protect these crucial apex predators and allow their populations to recover. Declining Great White Shark sizes should be an indication that we need to reverse our thinking. Rather than protecting ourselves from sharks, we need to protect sharks from humans.
Source: The Story of Size
I'm seasick !! NOW What ?
But what is sea sickness? Motion sickness is a generic term for the discomfort and associated vomiting induced by a variety of motion conditions, in this case, a boat.
Something in the waterSharks have a reputation (at least in popular culture) for being fearsome creatures, prone to attack with their sharp, scary teeth. But despite all the interest surrounding sharks, there are many misconceptions about these predators and the important role they play in marine communities.
Here are five myths about sharks BUSTED!
Myth #1: All sharks eat people
False. Actually, they don't. In fact, majority of sharks eat fish and invertebrates like squid. Shark attacks normally happen by accident due to poor visibility in the water, which is why there are so many more cases of people being bitten by sharks rather than killed by them..
Myth #2: Sharks aren't clever and have tiny, walnut-size brains
False. Sharks are actually one of the most intelligent creatures in the ocean, thanks to more than 400 million years of evolution. The animals used to be considered unintelligent, but in recent years scientists have found that sharks can display complex social behaviors.
Myth #3: All sharks are big and scary, and have lots of sharp teeth
False. There are more than 450 species of sharks, and they come in all shapes and sizes. The deep water dogfish shark is a tiny 8 inches (20 cm) long, while the whale shark can grow to be more than 40 feet (12 meters) long. Great white sharks, on the other hand, can deliver fatal bites with their rows of 300 serrated, triangular teeth.
Myth #4: If you're attacked by a shark, you should punch it in the nose
That's probably not a good idea. David Shiffman, a shark scientist at the University of Miami's Abess Center for Ecosystem Science and Policy suggested the best way to escape is to go for the shark's eye. Sharks have an eyelid-like barrier to protect them from prey thrashing around in their jaws, but it's not designed to shield from fingers.
Myth #5: Nothing eats sharks
While the largest sharks, such as tiger sharks and whale sharks, have very little to worry about from predators, the smaller sharks are not so lucky. Some shark species are incredibly small, and so they can make handy snacks for larger species. A few marine mammals, including orca whales, prey on sharks, too. In reality, a shark's biggest threat comes from humans
Source: LiveScienceRead more interesting shark facts here
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