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Shark and Oceanic Conservation in General

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TheunsH
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Shark and Oceanic Conservation in General

Unread postby TheunsH » Tue Apr 14, 2009 9:23 pm

Hi there to all you fellow forumites!

We are all nature lovers and nature conservation is and should be high on our agenda, actions and thoughts.

Part of general nature conservation is the conservation of our great oceans and the magnificent mammals, fish, etc that roam our oceans.

One aspect of the conservation of our oceans is shark conservation which is very dear to me.

Sharks are under threat either as a food source, as a result of sport fishing or due to anti-shark measures. Sharks are caught for their fins and this method results in the live animal being cruelly dumped back into the sea after its fins have been hacked off.

The United Nations estimates that internationally only about ten million sharks are harvested each year. Some conservationists, however, put the number at closer to a hundred million!! These are shocking statistics.

The shark-fin industry, concentrated in a few Asian trading centers, is secretive and wary of any attempts to regulate, or even investigate, its practices. To make matters murkier, most fisheries-management groups give little attention to sharks, because they are often considered by-catch…fish caught by accident given their low value per pound.

South African shark nets, put in place to protect mainly surfers and holiday-makers, capture between 800 and 2200 sharks per annum and catches are highest in those years when the sardines move close inshore during winter along the KwaZulu-Natal coast. More sharks are also caught in these nets during floods due to the fact that the dirty water may prevent sharks from detecting and avoiding the nets.

These nets are basically gill nets, indiscriminately catching harmless species, such as dolphins, skates, rays, whales and whale sharks. Shark nets cause irreparable damage to the eco system and need to be replaced by a more environmentally acceptable method. An electrical repellor (the Pod), may replace the gruesome nets. Due to the harsh nature of our coastline, the technology to supply this device with a reliable power source in the ocean is, unfortunately, still years away.

As far as I know the only shark species that is protected in South Africa is the Great White shark.
Ironically, 20 to 50 of this species are caught in South African shark nets each year, probably more than were killed by trophy fishermen before the ban.

People in general have a lot of misconceptions about sharks. The greatest culprit of them all was the film “JAWS”! Misconceptions such as “sharks are roaming the shore lines to catch humans” and “sharks are attracted by as little as a drop of human blood” are common. It is a highly debated question whether human blood attracts sharks at all. Sharks are attracted by fish blood and fish oil and to a great extend by vibrations and electrical impulses though.

Truth of the matter is that only 10 to 15 humans are killed internationally by sharks annually and about 200 are killed by hippos annually!

I had an awesome shark diving trip on The Protea Banks, KwaZulu -Natal, South Africa from 28 March to 4 April 2009. Herewith a few photos of these magnificent creatures roaming our “deep blue”! These photos were taken by Roland Mauz during dives. I don’t own an underwater camera (yet). Enjoy!

Black-tip shark

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Hammerhead shark

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Tiger shark.

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Zambezi shark. This is my favourite shark capable to survive in fresh water as well! These sharks are most of the time escorted by Remora fish also known as the pilot fish.

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Some info on the Protea Banks: The reef is located 8 kilometers offshore on the KZN South Coast and is not a proclaimed nature conservation and thus is shared by anglers and scuba divers alike. This reef is well-known as a shark diving spot with regular sightings of Zambezi (Bull), Tiger, Hammerhead, Black-tip, Ragged-tooth (Sand-tigers) sharks and many more. Regrettably it is a well-known fact that game fish anglers catch sharks, removing their jaws for trophy purposes, and dumping the carcasses back into the sea! How tragic. I am of the opinion that we need to protect all shark species.
Last edited by TheunsH on Sun May 24, 2009 12:10 pm, edited 1 time in total.

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Re: Shark Conservation

Unread postby Timepilot » Wed Apr 15, 2009 1:11 am

by making shark dives available to pander to people`s craving for (controlled) excitement and thrills, we are acting somewhat irresponsibly by showing people as `bait` in a way,


Interesting thought Scot, but what most divers don't realise is how often they are actually diving with sharks. Most divers look downwards and very rarely look up and so miss sharks that just cruise by overhead. I guess what I'm saying is that whether the dive is done purposefully to view sharks or not, they are there anyway. I'm coming up close to 1000 plus dives and I would have seen sharks on at least half of those.

One of the best sightings I ever had was on the Aliwal Shoal - my buddy and I were the last two in the group and a 2.5m scalloped hammerhead cruised past about 2 metres from us. We could'nt even snap it as the camera was fitted with a macro lens for the dive!!

Theuns, lets not stop at sharks though, as recreational divers a much greater concerted effort is required to protect our reefs and oceans! They are being destroyed by the hordes of "untrained" new divers who are entering the waters without a real clue as to how to swin on the beautiful reefs without causing damage - much like the speeders and other idjits that are talked about in the Kruger.
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Re: Shark Conservation

Unread postby Sparks » Wed Apr 15, 2009 1:52 am

DinkyBird wrote:Theuns, is shark cage diving also not causing a lot of harm by affecting the behaviour of sharks?

I am of the opinion that all creatures need to be respected and conserved. The earth is surely reliant on all the creatures, big and tiny, to keep the balance of nature.


To put your mind at rest a short answer.....No. It would be easy to think this possible but the fact of the matter is that the bait used by the shark operators is very expensive, unlike the normal train of thought sharks are fussy feeders (my experience is based on great whites only) and not the trashcan of the ocean as we were led to believe, to have the sharks actually eat the bait would be very expensive not to mention against regulation. The shark diving industry has strict rules that dictate behaviour and treatment of sharks and to get a licence is a major task, to lose it simple.

I am aware of studies that has shown that most sharks don't stay in an area for extended periods, normally about three to four weeks so to be habituated in this time would be difficult.

These massive fish are also quite skittish and do not approach humans willy nilly. They have been known to flee from the air bubbles from scuba tanks. I personally think the cages are there to protect the sharks and not the humans. Having had long discussions with operators one point that has been on the forefront is the passion these guys have for the sharks and the dive trips are based on education and conservation rather than entertainment.

Government regulations in this small sector is pretty strict and there are only a certain amount of licences granted with many more applicants waiting to lay their hands on one. The result of this is that the operators toe the line very carefully and do not even venture to sea in a dirty boat.

As apex predators these fish play a crucial role in our marine eco balance and desperately need to be protected. Education is half the battle won.

And finally NO I am not financially involved in the industry and do not punt any one operator, I am just concerned about the plight of sharks and our marine resources in general.
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Re: Shark Conservation

Unread postby TheunsH » Wed Apr 15, 2009 11:50 am

DinkyBird wrote:Theuns, is shark cage diving also not causing a lot of harm by affecting the behaviour of sharks?


DinkyBird, thanks for your question! I agree with Sparks on this. The answer is no.

In S. A. feeding fish and sharks is against the law, but baiting is permitted. Sharks are not dumb animals, chumming and baiting attracts sharks, the sharks soon learn there is no gain and leave.

Chumming only attracts sharks that are already in the area. Keep in mind that baiting is done a few kilometers offshore and not close to swimming beaches. Protea Banks for instance is 8 kilometers offshore. A very well known shark diving operator in the Western Cape says that "Chumming has got nothing to do with it. We chum with animals that occur naturally. Chum where there are no sharks and you don't get any. We have to show people these animals to ensure their survival. It's no different from viewing leopards and lions."

Shark diving has a vital role to play in re-educating the public and protecting the great white. This is a view shared with those who believe cage diving with sharks can help to improve the animal’s negative public profile.

No compelling evidence to connect shark tourism with an increase in shark attacks exists and in the vast majority of cases, attacks do not take place near shark dive locations.

Shark cage diving is done mostly in the Cape waters and a very popular Great White cage diving spot is Gans-Bay. In the warmer waters of KwaZulu-Natal shark dives are done without cages. Baited dives are done by a baited drum suspended below a surface buoy. The only purpose of baited dives is to get the sharks closer.

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Re: Shark Conservation

Unread postby TheunsH » Wed Apr 15, 2009 12:43 pm

Scot wrote:Sometimes wonder whether, by making shark dives available to pander to people`s craving for (controlled) excitement and thrills, we are acting somewhat irresponsibly by showing people as `bait` in a way, making sharks more accustomed to humans and possibly less likely to veer off instead of investigating.


Thanks for the comment Scot.

I think the advantages to conservation by making shark dives available out weight the potential accustoming of sharks to humans. It has never been proven that sharks see humans as prey or bait.

Humans are not part of a shark’s natural prey. During investigations it was found that sharks don't appear to be especially interested in the blood of mammals as opposed to fish blood. Most sharks prefer to eat certain types of invertebrates, fish and other animals. Some sharks eat mainly fish others eat other sharks or marine mammals. Some sharks are even plankton-eaters.

It has never been proven that sharks see humans as prey or bait during baited or non baited dives. In some very rare cases a shark may takes an exploratory bite and leaves its human victim, as humans are not its natural prey. Unfortunately, sharks are very powerful animals and severe damage may occur from such a bite.

It may be this pandering of our craving for controlled excitement and thrills that contributes to nature conservation after all! :thumbs_up:

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Re: Shark Conservation

Unread postby TheunsH » Wed Apr 15, 2009 1:23 pm

Timepilot wrote: what most divers don't realise is how often they are actually diving with sharks. Most divers look downwards and very rarely look up and so miss sharks that just cruise by overhead. I guess what I'm saying is that whether the dive is done purposefully to view sharks or not, they are there anyway. I'm coming up close to 1000 plus dives and I would have seen sharks on at least half of those.

One of the best sightings I ever had was on the Aliwal Shoal - my buddy and I were the last two in the group and a 2.5m scalloped hammerhead cruised past about 2 metres from us. We could'nt even snap it as the camera was fitted with a macro lens for the dive!!

Theuns, lets not stop at sharks though, as recreational divers a much greater concerted effort is required to protect our reefs and oceans! They are being destroyed by the hordes of "untrained" new divers who are entering the waters without a real clue as to how to swin on the beautiful reefs without causing damage - much like the speeders and other idjits that are talked about in the Kruger.


Great post Timepilot!

I once saw a program where a few Tiger sharks were tagged and traced by satellite on the Aliwal Shoal. At one point a few of them were traced swimming in the close vicinity of about 20 scuba divers. Afterwards the divers were asked if they had seen the sharks….NONE of them had!

My brother and I had a few dives at the Tsitsikamma National Park a few years ago. While diving and viewing a few Smooth Hound sharks on the bottom, other holiday-makers were swimming with their “boogy-boards” on the surface totally unaware of us and the sharks. In any case I don’t think those sharks were any threat to the swimmers though. :lol:

Awesome sighting of the scalloped hammerhead Timepilot. :clap: :clap:

You have an excellent point on the damage caused by divers not knowing how to enjoy the reefs without causing damage. I’ve seen many new divers having problems controlling their buoyancy smashing in and holding on to the reefs causing damage!

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Re: Shark Conservation

Unread postby TheunsH » Wed Apr 15, 2009 2:09 pm

JenB wrote:I would compare free diving with sharks similar to one walking through KNP and cage diving similar to watching lions from your car.

These are not man hunting monsters but rather wild animals, finely tuned for survival and in desperate need of conservation.


Thanks for your comments JenB. :clap:

I agree hundred percent with your comparisons. I haven’t done a cage dive yet and I don’t think I’m interested in doing cage diving. I prefer doing a non-cage shark dive (Scuba) of which I have done 26 the past 5 years on the Protea Banks. Only 2 of those 26 dives were baited dives and 24 were non-baited dives. Furthermore I prefer non-baited dives and during all of those 24 non-baited dives we saw sharks!

One aspect relating to your comparison though…Getting from the boat to view sharks is no problem for me but getting out of my car to go and take a few close-ups of lions is another story. I have a far greater fear (Let me rather calls it respect) for say lions than sharks. :lol: :lol:

You are correct in saying that sharks are not hunting monsters, all shark divers are living proof of that! :thumbs_up:

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Re: Shark Conservation

Unread postby Timepilot » Thu Apr 16, 2009 1:21 am

Theuns, on my first outing as an instructor in Soddies back in '91 we had a the most magnificent conditions over the weekend.

On our first trip out to the reef we "bumped" into a whale shark, so it was masks and fins on and in the water, giving the students an awesome experience. The second trip out we came across a humpback and the performance was duplicated. Third trip was another whale shark - so in we went again.

Vis was close on 50m over the weekend and on our last dive on the Sunday we were drifting along at about 11m. I had one of the students holding the buoy and I was slightly above and behind the group keeping an eye on what was happening when I looked ahead and, just lying there, was a 2m raggie. I gathered the students and arranged them behind the shark along the edge of the gulley and we spent the last 10 minutes of the dive just watching. It was the perfect way to end the weekend (incidentally, all of the students went on to further diving qualifications!)

Before anyone makes a comment about diving in with the whale sharks, I pretty much kept control of the situation - having done probably 15 dives where we've encountered them previously. The students were swimming about 4 to 5m either side of the whale shark as it was cruising. We got about 5 minutes with each of them without disturbing them before the completely outpaced us.

These have to be one of the most magnificent creatures in the ocean, and their sheer size is breathtaking. I've done the whale shark dives up in Ningaloo here in West Oz which are strictly controlled. A lot of the greenies here were up in arms about these diving trips saying that they would scare the sharks away from their normal migratory routes. This has not proven to be the case with constant numbers coming each year.
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Re: Shark Conservation

Unread postby Sparks » Thu Apr 16, 2009 1:37 am

TheunsH wrote:
One aspect relating to your comparison though…Getting from the boat to view sharks is no problem for me but getting out of my car to go and take a few close-ups of lions is another story. I have a far greater fear (Let me rather calls it respect) for say lions than sharks. :lol: :lol:

You are correct in saying that sharks are not hunting monsters, all shark divers are living proof of that! :thumbs_up:


I think it is a case of having a better understanding of shark behaviour than lion behaviour. :twisted:
It is a pity that this thread has to disappear with all the other frivolous banter in chit chat as this can do wonders to change people's perception of these magic creatures
In the cape it is against the law to free dive with sharks commercially and that prompted my claim of the cages being there to protect the sharks. I must confess that I would think twice before going down with bull sharks and great whites only with someone that knows them well. What worries me is they can sense your heart rate and unlike lions they know my stomach is in my hoodie :lol:.

It is sad that most people only see the sea as a big pool to lie next to and hardly ever take the time to go down to the rocks at low tide at night with a torch to see what they are missing. With a bit of luck and a few more posts like this it could be changed :thumbs_up:
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Re: Shark Conservation

Unread postby TheunsH » Thu Apr 16, 2009 10:57 am

Hi there Elzet and welcome to this thread. :clap: :clap:

Comparing this thread to Gorillas in the Mist is spot on. Gorillas in the Mist was a great movie and contributed greatly to the conservation of gorillas.

Thinking of it, during that movie there were scenes where the only thing you saw was the beautiful dense jungle covered by this blanket of snow-white mist and the next moment, as in appearing silently from nowhere, there they are…the gorillas, wow! :shock:

The same goes for shark diving especially when drifting slowly, silently, your senses straining, in total harmony and peace at 30 meters with perfect buoyancy control in this magnificent big blue column of water with the dark ocean floor silently moving by revealing her secrets. The only audible sound you hear is the peaceful rhythm of the first and second stages of your demand valve opening, closing, opening and closing giving you that so needed breath of life and you realizing again that you are only but a guest in this great vast “big blue”. Out of nowhere there they are…sharks gliding peacefully by, wow and wow again!! :big_eyes:

Diving with sharks is a passion and scuba divers in general are passionate about the conservation of our great oceans. When are you taking the plunge? It seems, from your post and knowledge of the creatures of our oceans, that you may be a good candidate to go scuba…again. :tongue:

Back on a serious note, yes Zambezi (bull) sharks are tolerant of fresh water. In January 2009 a Zambezi was caught, tagged and released 5,5 kilometers upstream in the Breede river, Western Cape. It was a pregnant female and she was 4 meters in length – by far the largest known specimen of the breed to date.

The scorpion fish you have seen while skin diving at a depth of 2 feet is maybe the 3rd or 4th most dangerous creature of our ocean. Scorpion fish come from the family Scorpaenidae, which includes lionfish and stonefish. The fins of these prickly fish carry poisonous venom. A scorpion fish sting causes intense pain and swelling at the site of the sting. Swelling can spread to affect an entire arm or leg within minutes.
Other symptoms can include:
• Blood pressure changes -- may be high or low
• Delirium
• Diarrhea
• Fainting
• Heart rate changes -- may be fast or slow
• Nausea and vomiting
• Paralysis
• Seizures
• Shortness of breath and even death.

Elzet, shark netting to protect swimmers are a highly debatable issue and there are no easy answers. In 1986 a very well-known conservationist and his team assessed the risk of “Shark attack’ off the KZN coast and their conclusion was there was none and the shark nets should be removed. :hmz:

Baited hooks suspended from an anchored buoy and referred to as drum lines are also used. The drum lines have subsequently created their own horror story and are nothing more than a feeding and killing station for sharks.

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Re: Shark Conservation

Unread postby TheunsH » Thu Apr 16, 2009 12:07 pm

Sparks wrote:What worries me is they can sense your heart rate and unlike lions they know my stomach is in my hoodie :lol:.


:lol: :lol:

Sparks, I agree with you on the issue having a better understanding of shark behaviour than lion behaviour! :thumbs_up:

Many moons ago we went on one of the walking safaris in KNP (close to Letaba). We didn’t see any lions though but I think maybe I should go on another safari or one of the day-walks with the possibility of spotting a few lions close-by. I think seeing a lion on foot and the guidance of a Ranger may teach me something about lion behaviour.

Great point as to what this thread can do to change people's perception of these magic creatures (sharks). Maybe we should change this thread’s name to something else like “Oceanic Conservation” to broaden the scope to ocean conservation in general. Such a thread can then include all sea life like dolphins, etc. What do you think? :hmz:

I wasn’t aware of the fact that it is against the law to free dive with sharks commercially down in the Cape!

Diving on the Protea Banks is done professionally by the local dive operator. All dive masters there are experts when it comes to shark diving and divers are always accompanied by the dive operator’s dive masters. They have vast experience and the dive operator has been operating on the Banks since 1994 without any major shark dive related incident. You will be in good hands.

I also agree with you on your point about people seeing the sea as a big pool to lie next to. I think in many cases it’s a situation of “out of sight out of mind” and people doesn’t care about ocean conservation because they don’t know what is going on underneath the waves.

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Re: Shark Conservation

Unread postby TheunsH » Thu Apr 16, 2009 12:51 pm

Timepilot, it sounds like you had many great dives here in South Africa. I’m feeling :mrgreen: :mrgreen: of your great Whale shark sighting.

I’ve never had the privilege seeing a Whale shark while diving and I hope to see one soon! I’m like some visitors going to the KNP for 20 years and never had the privilege of spotting a leopard or a pack of wild dogs…I think after 20 years it would became a bit of an obsession though. :x

Your dive and description about the Ragged-Tooth shark and the visibility sounds awesome! Winter is now on it’s way and it’s time for some Raggie diving on the Aliwal Shoal and Protea Banks where on a good day, divers can encounter up to 200 sharks in an area smaller than half a rugby field.

One day I will visit Ningaloo for some excellent diving. :thumbs_up:

Herewith a photo or 2 about Spotted-Ragged-Tooth sharks also known as Sand Tigers (USA) and Grey Nurse sharks (Aus). These pictures were taken by Roland Mauz:

Image

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Re: Shark Conservation

Unread postby TheunsH » Fri Apr 17, 2009 5:40 pm

Timepilot wrote:Theuns, I dived and snorkelled Natal and Cape from the mid 70's until I left in '92.

Spent a few of my holidays in Umzumbe in the late 80's / early 90's and used to go up to Aliwal every second day for a couple of dives. Loved Raggie Cave with it's amazing sight of 30 or 40 raggies swimming in a circle.


:thumbs_up: :thumbs_up:

Are you still an instructor Timepilot?

Elzet wrote:
Poetic, to say the least. :popcorn:
And the conservation info contained in all posts - terrrrrific! :thumbs_up:

:yaya:


Thanks Elzet, diving can urge one to get a bit poetic! :lol: :lol:

Getting back to the fear of sharks....and I think a good point to address as a starting point of understanding sharks in general!

Many people are afraid of sharks and the main fear is the fear of a shark attack while swimming in the surf.

Analysis of shark attack records shows that a high proportion of attacks took place under conditions that were considered unwise for safe swimming in the first place.

Such unsafe conditions include the following:

Swimming at dawn, night and sunset. Many shark species are very active during these times.

Swimming in dirty water. Sharks are attracted to river mouths due to refuse and waste from rivers. Some of our beaches have a problem with the lack of toilet facilities and sewage flowing into the ocean. Human waste attracts sharks. Sharks are curious and will investigate.

Swimming with bleeding fish on a spear. Sharks are attracted to fish blood as well as the vibrations made by injured fish.

It is said that if high risk situations are avoided, incidence of shark attacks would drop effectively to insignificant levels.

Experts say that shark attacks are usually “random attacks”.

Furthermore it is said that an indication of potential shark activity close to the beach may be large amounts of bait-fish near shore, for instance sardines; congregated, excited diving birds, such as seagulls, swarming a given area of ocean nearby and dead or injured marine mammals on or near the beach. Notwithstanding popular belief, dolphins do not necessarily indicate an absence of sharks nearby.

I hope these facts will ease your fears a bit. And one last fact, do not urinate in the water if in Great White shark territory (white sharks are thought to follow the scent of mammalian urine to hunt). :wink: :wink:

Great Whites do not tolerate "water-toilets"! :lol: :lol:

My questions to all of you:
What do you think of sharks?
Are you afraid of sharks? And if so, why?
Have you ever seen a shark in the ocean?
Did you perhaps had a close call with a shark or perhaps know somebody who did? If so, what happened?

Theuns.

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Re: Shark Conservation

Unread postby Elzet » Sat Apr 18, 2009 6:38 pm

I think I answered one of your questions incorrectly. In fact, I've seen stingrays 'down under' - and they are classified as part of the sharks species. I'll never forget that 'silent' motion - soft sweeping of the wings - or that one that was partially buried in the sand, looking like a sleeper from a railway line - as this was the only indication that something was buried in the seabed... his back protruding through the sand. And no, I'm not afraid of them... So no and yes to your question.

Here are some information on them:

Stingrays are commonly found in the shallow coastal waters of temperate seas. They spend the majority of their time inactive, partially buried in sand, often moving only with the sway of the tide. The stingray's coloration commonly reflects the seafloor's shading, camouflaging it from predatory sharks and larger rays. Their flattened bodies are composed of pectoral fins joined to their head and trunk with an infamous tail trailing behind.

While the stingray's eyes peer out from its dorsal side, its mouth, nostrils, and gill slits are situated on its underbelly. Its eyes are therefore not thought by scientists to play a considerable role in hunting. Like its shark relatives, the stingray is outfitted with electrical sensors called ampullae of Lorenzini. Located around the stingray's mouth, these organs sense the natural electrical charges of potential prey. Many rays have jaw teeth to enable them to crush mollusks such as clams, oysters, and mussels.

When they are inclined to move, most stingrays swim by undulating their bodies like a wave; others flap their sides like wings. The tail may also be used to maneuver in the water, but its primary purpose is protection.

The stingray's spine, or barb, can be ominously fashioned with serrated edges and a sharp point. The underside may produce venom, which can be fatal to humans, and which can remain deadly even after the stingray's death. In Greek mythology, Odysseus, the great king of Ithaca, was killed when his son, Telegonus, struck him using a spear tipped with the spine of a stingray.

Some other interesting information on shark conservation, in particular stingrays (can you believe that people are that stupid?, i.e. possibly 'taking revenge' on stingrays?):

The natural injustice of the death of Steve Irwin, the daredevil conservationist who wrestled with crocodiles and dangled cobras, but was killed by a relatively docile fish, has apparently motivated some of his most ardent supporters to wreak revenge.

Eight days after the documentary maker was killed in a freak encounter with a stingray while snorkeling off the north Queensland coast, and while his native Australians continue to mourn him, the authorities are investigating the possibility that the species that took Irwin's life is being targeted in acts of retribution.

Up to 10 apparently mutilated stingrays have washed up in coastal waters since his death, prompting Queensland state officials to call on fans of the self-styled "wildlife warrior Australian bloke" not to retaliate against the species that killed their hero.

Two stingrays - typically placid creatures - were found dead yesterday with their tails sliced off at Deception Bay, north of Brisbane, adding to the toll of eight already discovered since Irwin's death in waters further north.

The actual stingray which delivered the fatal blow to Irwin as he swam in shallow waters with a cameraman to film "stuff on the reef and little animals" for a programme featuring his eight-year-old daughter could, of course, still be alive.

"We do find dead stingrays with their tails cut off from time to time. People usually do it if they are worried about getting stung by a stingray, or they just do it maliciously, but it is pretty rare," said Wayne Sumpton, a senior biologist in Queensland's fisheries department.

"We do not know if these incidents are motivated by Steve Irwin's death. At the moment that is just speculation."

Conservationists who worked with the documentary maker have been swift to condemn any form of retaliation against the animal kingdom for his death, pointing out that cutting the tails off normally placid fish conflicts with Irwin's conservationist beliefs.

Killing stingrays, said Michael Hornby, executive director of Irwin's conservation group Wildlife Warriors, is "not what Steve was about".

"We are disgusted and disappointed that people would take this sort of action to hurt wildlife," he said. "It may be some sort of retribution, or it may be fear from certain individuals, or it just may be yet another callous act toward wildlife."

Irwin died after the serrated barb of a stringray penetrated his heart. Although the venom embedded in the tail spines of stingrays can kill small creatures and cause acute pain to humans, it is extremely rare for the shy fish to kill humans.

It is thought the stingray that killed Irwin struck its tail with a reflex powerful enough to puncture a hole in the 44-year-old's chest in what is said to have been only the third recorded fatal stingray attack in Australia.
“Life is too short to wake up with regrets. So love the people who treat you right. Forget about those who don’t.” - Harvey MacKay

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TheunsH
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Re: Shark Conservation

Unread postby TheunsH » Sat Apr 18, 2009 11:18 pm

I just saw this amazing program called Sharkman featuring Michael (Mike) Rutzen from SA free diving and scuba diving with Great White sharks.

To get some terminology right here…free diving is the sport of diving without the aid of breathing apparatus and is normally done wearing a wetsuit, flippers, diving goggles, snorkel and a weight belt. Scuba diving is done by wearing the same gear and scuba gear. The abbreviation, SCUBA, means "self-contained underwater breathing apparatus"

The program is dealing with tonic immobility which was discovered by a Dr Samuel Gruber in the Bahamas on Lemon and Caribbean Reef sharks.

Tonic immobility is the trans-like or sleep-like state occurring with some species of sharks. Many other animals like beetles, snakes, etc, are capable of appearing to be dead to an observer, while otherwise alive. This could either be a reflex action, as in tonic immobility, or a defense mechanism for avoiding predators.

The program features Mike toughing Great White sharks, swimming with them and even holding onto their dorsal (on the back) and upper caudal (tail) fins hitching a ride! He states that he is hunting for knowledge and I think he is one of the great pioneers in the field of shark conservation and tonic immobility.

When looking at the program it becomes clear that Great White sharks are not this killing monsters of the deep. Mike first ascertains the “mood” of the Great White, when the shark is a “player”, as he puts it, he feels comfortable to enter the water. He states that Great Whites have different personalities…some are "super curious" and others are "super friendly".

It is crystal clear that he and Dr Samuel Gruber is passionate about sharks and the conservation of sharks where they passionately speak about facts like 100 million sharks are caught annually…50% of those by accident in long-lines dragged behind huge fishing ships, shark fins are hacked off and the bodies are dumped back in the ocean, sharks don’t deserve their bad reputation, and shark attacks are blown out of proportion due to factors such as the media, etc.

The program demonstrates how tonic immobility is done on sharks. It shows how by tickling or rubbing a sharks nose or snout such shark goes into tonic and by turning a shark around onto it’s back the shark becomes totally sleep-like.

Notwithstanding popular belief all sharks needn’t keep on swimming to breath. Aquatic respiration is the Biological process whereby an aquatic animal obtains oxygen from water. While moving, water passes through the mouth of the shark and over the gills — this process is known as "ram ventilation". While at rest, most sharks pump water over their gills to ensure a constant supply of oxygenated water. Some shark species had lost the ability to pump water through their gills and are spending their life constantly swimming. These species are obligate ram ventilators and would presumably asphyxiate if unable to stay in motion.

The Spotted Ragged-Tooth sharks are able to pump water over their gills to ensure a constant supply of oxygenated water. Tonic immobility occurs naturally during the mating process of Ragged-Tooth sharks. Mating here isn’t a very loving affair. The mail bites the female and most females carry scars from these mating bites.

Thinking of it…maybe the males are a bit too passionate! :lol:

After mating the male pushes the female on her back putting her in tonic immobility. Tonic immobility may last for 15 minutes and the purpose is to have her eggs fertilized. Something very interesting is the fact that only 2 pups are born (70 cm long) as a result of intrauterine cannibalism! :shock:

Well, I hope you have enjoyed it. :thumbs_up:


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