Monday, February 6, 2012

Blue Shark Facts

blue shark 
Blue sharks, Prionace glauca to give them their Sunday name, have had a bad Press, unfairly in my opinion. 

Those who will tell you this shark is dangerous are those who want to fish them from the sea.

In reality, they are timid beasts who would rather swim away from a confrontation.

If you are dying in the sea, perhaps from falling overboard or even, God forbid, part of a shipwreck, blue sharks may well congregate too close for comfort.

Say “Boo!” to them, and they will quickly disappear.

At 6 to 10 feet in length, they are probably bigger than you, but harmless in the main (in the main, get it?)

So, you are floundering in the water after a shipwreck and you see sharks approaching, how do you know if it is a blue shark?

The clue is in the name.

Blue sharks are blue – dark blue on top, light blue along the flank, and white underneath. 

Streamlined, they are long, slim fish with big pectoral fins – those are the ones on the sides.

Pointed snouts and large eyes, and you have a typical blue shark.

Whatever you do, don’t play dead.

They happily feed off carcasses in the water, yours included. 

This is what sharks do; it is their job to keep the oceans clean, and stinking carcasses have to be disposed off somehow.

And they need to eat.

While their normal diet consists of fish, squid, octopuses and other ‘sea things’,  the stomachs of blue sharks have been known to contain blubber from whales and porpoises.

They hate tuna, apparently, so eat your fill before you end up shipwrecked.

An absolutely fascinating fact about blue sharks (to me anyway, sad I know) is that they swim in groups or schools or whatever you like to call them, of equal sized fish of the same sex. 

Doesn't that remind you of school? Hockey, anyone?

Blue shark mothers give birth to anywhere between 4 to 135 pups per pregnancy, according to Wikipedia.


Can you imagine the size of house you would need if that was your offspring?

Female blue sharks reach sexual maturity at only 4 or 5 years of age, which is exceptionally young for the shark family, as most of them follow a similar pattern to humans, not reaching maturity until they are in their teens, at least.

They are pregnant for between 9 and 12 months, according to current knowledge, and when the scientists have discovered the exact time, I will publish it.

Female blue sharks have thicker skin than their male counterparts.

No really. 

Nothing to do with being insulted, although if they went to Britain and had 135 children, and needed social security to pay for the mansion they would need to live in, they’d need to develop one.

No, in the blue shark world, the male bites the female when he wants to initiate sex. 

Seriously, this is true! 

This only goes to prove what I said. 

All we need to say to the highly strung and nervous blue shark is “Boo” and they disappear.

We should teach the female how to say it. Instead, God gave them thick skins, which grow thicker as they age.

Blue sharks are exceptionally dangerous to fishermen.

All sharks, when caught and are lying a boat’s deck, have the ability to twist their bodies round lightening quick to bite their captors, even when they look dead.

Blue sharks have honed this talent down to a fine art.

Fishermen are scared of them, and have declared them dangerous because if this.

One up to the blue shark! Go get ‘em!

I admit to not understanding the joy of fishing a sea creature that can’t be eaten (well it can, but it’s not the best) and can only be finned for the pleasure of certain Asian countries who choose to base their cuisine around something that even they admit is tasteless!

The blue shark is classed as near threatened on the IUCN list of endangered species which probably means it isn’t threatened at all. That’s not the point (it has 135 babies at a time), the point is they could be.

Great White Shark Facts

great white shark spyhopping

  • The scientific name  of the Great White Shark is Carcharodon Carcharias. It is also known as the White Pointer or just as  the White Shark. 

  • Their favourite foods are pinnipeds – seals and sea lions, but in reality they will eat or attempt to eat anything in the ocean, including sea birds, as well as other fish and sharks. Given a choice, they prefer foods high in fat which will boost their energy levels for longer while keeping them feeling full.

  • In a practice known as ‘spyhopping’, great white sharks are one of the few shark species who are known to lift their heads right out of the water to look around. They may do this to see objects, but it is thought this helps them to smell their prey better.

  • Very little is known so far about their mating or breeding habits. It is known that they are ovoviviparous, meaning that the eggs hatch in utero and stay there until birth, with the bigger and stronger babies eating the smaller, weaker ones.

great white shark

  • A female great white is pregnant for 11 months.

  • Great white sharks are fish, but are warm-blooded fish.

  • The great white is the shark responsible for more attacks on humans each year that any other shark. Most of those attacks are only a test bite, taken because they are inquisitive. Because of their incredible size and strength of their jaws and teeth, more of these single bites are fatal due to the damage they inflict.

  • Great whites grow to a maximum of 20 feet on average, and can weigh up to 4,000lbs.

  • Great white sharks often travel in packs, known as ‘clans’. When one clan meets another, they interact in a friendly and inquisitive fashion.

  • Like a lot of other types of fish, and all sharks, the great white has an extra sensory organ in their head called the ampullae of lorenzini which allows them to detect the electrical fields of other animals as they move. Those sensors in the great white are highly tuned to detect weak signals given off by both distant prey or injured fish or mammals.

  • Great white sharks live an average of 30 years, but they are believed to live until 100. As they are now being tagged and studied in detail, this theory will be known or disproved in your lifetime.

  •  Due to over-fishing and shark finning, the great white shark is now listed as vulnerable on the IUCN list of endangered species.

Wednesday, February 1, 2012

Are Shark Attacks Common?

great white shark  Credit: Babbitt  

Shark attacks are not common, in fact they are very rare indeed. 

That is why they makes the world’s Press when they happen.

At the same time it is important we learn that sharks are at the top of the oceanic food chain

We humans are top of the food chain on land. We belong in the land. They belong in the sea. 

While it would be nice to surmise that "never the twain shall meet", in reality we do meet, because we go into the sea.

It is worth pointing out that sharks do not come on land, therefore when we meet a shark, it is on their territory, not ours.

Even so, with millions of us taking to the waters on various pursuits daily, whether that be fishing, diving, bathing, surfing or taking part in any water sports, or even being shipwrecked at sea, there are still relatively few encounters between shark and man.

There are less than 100 reported shark attacks a year, and only a small percentage of them are fatal.

Sharks are naturally inquisitive creatures, and many shark attacks can be put down to a shark tasting us, to see if we are food. 

We are alien to them; they do not know what we are.

Very seldom do sharks continue to attack and bite us after the first taste. 

I suppose we are not salty enough, or perhaps because we have too many bones.

Commonly people who have been bitten by a shark will see the shark back off, giving the victim time to get out of the water.

This is especially true of great white sharks, the type of sharks who are responsible for the most attacks on humans.

The problem with being given even a ‘friendly’ bite by a great white, is that their teeth are designed for tearing, and they are very big, powerful animals, so sometimes we die from just one bite, especially if an artery was torn.

Torn arteries in shark attacks

Arteries carry oxygenated  blood away from the heart at tremendous speeds, so when one is severed, the blood spurts out at a frightening rate. We can lose so much blood so quickly in a really short space of time, that our internal organs shut down, and we die.

A severed artery needs to be stopped up within 3 minutes.

That is why it is of vital importance that everybody learns how to stop someone bleeding  to death, or slow down the blood loss until emergency services arrive.

Sharks usually only bite once then realise their mistake

Great whites aside, some sharks do continue biting after the first taste. 

Many smaller sharks go into what could be described as a feeding frenzy, when they just lose control and bite and snap at everything in the water, including each other if there are a shoal of them.

oceanic whitetip shark
 Included among those are oceanic whitetip sharks.

Then there is the bull shark.

This shark is commonly called the ‘pitbull of the sea’ and for good reason. It’s just a nutter!

Bull sharks when they attack become just like a rabid pitbull, biting and attacking and not stopping, which is why there are a higher percentage of deaths in people attacked by bull sharks than there are for great whites.

bull shark
The vast majority of types of sharks are timid creatures, who would swim away rather than face confrontation. 

Even out of the big 3   - the white, tiger and bull shark, most of them totally ignore us even when we swim in the same area of water as them.

However, because of the damage they are capable of inflicting, it is always better to vacate the water the minute the shark spotters tell you there is a shark in the area.

We just never know when they might attack.

If we want to avoid shark attacks, then we have to give them the respect they deserve when we are in their homes, which are the oceans and seas of the world.