Endangered Hammerhead Sharks

Plight of Hammerhead Sharks

The scalloped hammerhead's population has been reduced by 99% in the past 30 years in some parts of the world, due to overfishing and finning, and it is reckoned they will be extinct in our lifetime.

This has led to an increase in cownose rays,which were a popular choice of food for sharks, and this is turn has meant a sharp decrease in bay scallops (the food of choice of the cownose rays) around which an industry collapsed when there were none left to catch.

Studies have shown that ALL shark populations have been reduced by 50% in the north-west Atlantic in the past 30 years, and that ALL sharks could be eradicated forever in our lifetime, if steps are not taken to protect them.

Both the Great Hammerhead (Sphyrna mokarran) and the Scalloped Hammerhead (Sphyrna lewini) are on the International Union for the Conservation of Nature (IUCN)'s list of endangered species.

Hammerhead Sharks

Hammerheads are aggressive hunters, feeding on smaller fish, octopuses, squid, and crustaceans. They do not actively seek out human prey, but are very defensive and will attack when provoked. Photograph by Brian J. Skerry
Hammerheads are aggressive hunters, feeding on smaller fish, octopuses, squid, and crustaceans. They do not actively seek out human prey, but are very defensive and will attack when provoked. Photograph by Brian J. Skerry

Hammerhead sharks are found on continental shelves in the warmer and temperate oceans of the world. There are nine identified types in this species, the largest being the Great Hammerhead, which can reach 20' in length and weigh 1000lbs.

Of these nine, only 3 are considered to be potentially dangerous to humans - the great ,the smooth and the scalloped hammerheads.

They can often be seen in shoals heading for the cooler waters in the heat of summer. They are best identified from their tall pointed fin and their colouring which is grey/green on top and white underneath.

Their teeth are heavily serrated and triangular.

The hammerhead shark's wide set eyes with 360 vision, gives it a much better vision than most other sharks, and it's reckoned that the hammer shaped head that gives it its name is used for its sensory organs to better help it detect food.

Hammerhead Sharks have all round vision.

Scientists have long argued over exactly why hammerhead sharks have such strangely shaped heads.

Now a team of scientists from Florida Atlantic University and the University of Hawaii in Manoa have conducted experiments that prove that hammerhead sharks have 360° vision.

By placing a variety of sharks with different head shapes into a large tank and shining lights from different angles, they were able to work out each animal’s reaction through special sensors placed on their skin to measure brain activity.

Through this method they were able to prove that hammerheads have anterior binocular vision.

This allows them to see directly ahead AND accurately judge the distance of any prey they spot. Basically this is a panoramic vision that allows them to see all round at the same time – up, down, in front and behind, simply by slightly moving their head from side to side as they swim.

This would be useful for them not only for catching prey, for avoiding becoming prey to larger sharks.

The hammerhead takes 16 years to mature enough to carry young and when she does, she often has litters of 20 - 40 at one time! However, they do not stay with the young, from birth they have to fend for themselves, and many do survive to adulthood.

A scalloped hammerhead shark. Photograph: Stephen Frink/Corbis
A scalloped hammerhead shark. Photograph: Stephen Frink/Corbis

Where are all the hammerhead sharks going?

It seems the vast majority of sharks are sold in Asian markets, mostly for their fins which have a terrifically high value now, which is then turned into shark's fin soup.

Once upon a time it was only the rich in China who could afford it, but now the middle classes are catching up due to the economic boom of the last 20 years.

What protective measures are being offered hammerhead sharks?

The hammerhead shark has not been seen in the Mediterranean Sea since 1995.

There have been moves by various authorities worlwide to protect the sharks, but the legislation is being totally ignored and unenforced. For example, at the world heritage site at the Galagapos Islands finning is banned but it goes on, and openly.

In Europe, only Croatia and Malta have extended protection towards sharks in their waters of the Mediterranean Sea.

Britain is one of the 5 European nations that continue to permit fins to be removed at sea, which of course kills the shark whose body is then dumped overboard.

There are no regulations in place in international waters to protect sharks, who are at the top of the oceanic food chain, but whose loss will result in an ecological imbalance which could have devastating consequences for all of us.


I RECOMMEND YOU WATCH THIS SHORT FILM.

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Comments 22 comments

bearclawmedia profile image

bearclawmedia 6 years ago from Mining Planet Earth

Good hub, good vids. Thanks for sharing.


IzzyM profile image

IzzyM 6 years ago from UK Author

Thanks David:)

I never thought I'd end up writing about trying to save them, but the more I learn about them the more I want to do something, and the best thing I can think of is to write about them online and hope it reaches the public's attention.


Army Infantry Mom profile image

Army Infantry Mom 6 years ago

Awesome hub,.. i really love these creatures, they are so fasinating. I too hope many people get the chance to drop by and read this hub,.. What a shame it would be if my Grandkids(which I dont have yet) would never be able to see this creature except from out of a book. A big HOOAH to you !!! :)


IzzyM profile image

IzzyM 6 years ago from UK Author

Thanks a lot:) Your comments mean so much to me (and to the sharks who are being wiped out).


marcel285 profile image

marcel285 6 years ago from New Zealand

I really enjoyed the video. I have a fetish for sharks, they are extremely awesome creatures, and i can't get enough of them! Excluding seeing them face to face of course, unless their behind aquarium glass!


IzzyM profile image

IzzyM 6 years ago from UK Author

LOL a bit the same as myself, I suspect. I don't ever want to be face to face with one, but neither do I fancy a life without them, if you know what I mean.


LRobbins profile image

LRobbins 6 years ago from Germany

Fantastic hub, very informative. Thanks for writing about such an important issue and trying to save the hammerheads before it's too late. I've put a link from my hub to this one as well.


IzzyM profile image

IzzyM 6 years ago from UK Author

Thankyou!

I've written a few articles about sharks; many of them are on the critically endangered list and its only by writing about them and spreading the word that they have any hope of salvation. Public opinion is everything if we are to force nations into doing something.


lezel bee 6 years ago

the fact that these animals can be extinct has really caused me to be worried even more so when i have to explain to my children why we dont have these marvellous sea creators anymore. people must educated themselves and see that not only are humans on the earth to serve a purpose but so does these animals too


IzzyM profile image

IzzyM 6 years ago from UK Author

Exactly, I totally agree, Lezel. Thanks for commenting :)


wolfpack5 profile image

wolfpack5 6 years ago from Alberta Canada

very kool hub lzzy, if you dont mind I will use some of this for my hub as well. You are a great writer and im really not. but I am going to try to use this awesome info from here. :)

have a great day...


IzzyM profile image

IzzyM 6 years ago from UK Author

Thanks for saying that though I don't think I am a great writer! Try my best that's all we can do! Yes please do go ahead and write that hub, the more information we can get 'out there', the greater the public will realise the dangers to the existence of the sharks of our waters. Their demise will mean the rise of some other crittur and the ecological balance of the seas will be upset with goodness knows what dire consequence.

I'll look out for that hub!


Gigi 6 years ago

Thanks for this hub! I am doing a school project on the endangered shark, and this was very helpful. I appreciate your work on trying to save these gorgeous creatures!

Thanks again!


IzzyM profile image

IzzyM 6 years ago from UK Author

Hmmm...doubt if I'd describe thm as 'gorgeous', but each to their own I suppose!

I think you must have found out by now that most of our sharks are endangered, as well as many other creatures of the sea.

Perhaps you could organise a 'youth against the mass extinction of our sea creatures' venture, or something? In the next year or two, expect to see the last of the Atlantic Bluefin Tuna as well.

I'm too old to get involved. The best I can do is write about it.

Man does not have the right to make another creaure extinct. Join Greenpeace or Sea Shepherds and stop this abomination!

Thanks for commenting :)


andrewkeet 6 years ago

Thanks for this hub. Sharks are in real trouble and the only way is to educate the public about these fantastic animals. To learn more about them view: http://www.sharks.org.za


IzzyM profile image

IzzyM 6 years ago from UK Author

You're welcome Andrew. Thanks for the link :)

If you are involved with this site, please feel free to link my hub to it. The more interest we can generate in these creatures, the better their chance of survival is.


fishing 4 ever 5 years ago

WOW I did not no they were in so much danger. I go fishing and i DO NOT kill shark. I cann't catch them anyway. i wish i got stop those people. What did THE SHARKS DO TO THEM.But i can not do anything i am just a kid. :(


jamiesweeney profile image

jamiesweeney 5 years ago from Philadelphia, PA

Great hub!

Hammerheads are cute! People must stop hunting them.


jeremy 5 years ago

Shark hunting should be alleigle. Great whites and mako are rare.


IzzyM profile image

IzzyM 5 years ago from UK Author

They are rare. They are also dangerous, but that does not give us the right to hunt them down in the seas which is their territory, not ours. So yes it should be illegal, as you say.


theherbivorehippi profile image

theherbivorehippi 5 years ago from Holly, MI

It makes me so furious to hear of any animal endangered. This is their planet, we are guests. Great information here. I shall tweet and share!


IzzyM profile image

IzzyM 5 years ago from UK Author

Thanks :) The hammerhead is only one of the sharks endangered now. They reckon that within 50 years, all sharks may be wiped from the world's oceans thanks to overfishing and finning, if international agreements are not reached.

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