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07/06/2007: "SHARK STORIES ............ the most interesting points"
Background
The grey nurse is found in many parts of the world. In the U.S. they are called sand tiger sharks. In South Africa ragged tooth sharks. Average length today is six to eight feet with rare adults to 12-13 feet.
Grey nurse prefer rocky reef gutters, usually but not always on the northern side of islands where theyrest by day and feed by night upon mulloway, yellowtail kingfish and other delicious pelagic fish.
East coast Australian shallow water sightings by scuba divers is throughout NSW. Too deep for compressed air divers are sharks on deep reef such as The Peaks off Sydney and elsewhere further south.
It should be assumed grey nurse live anywhere on the continental shelf and possibly travel while following pelagic fish for their food.
Seen elsewhere: Nine Mile Reef, Flat Rock, Flinders Reef and other reefs east of Brisbane, Queensland.
Wolf Rock near Double Island Point. Northern migration to New Guinea waters off the eastern tip – other sightings, Lady Musgrave Island off Gladstone, Broome W.A. and possibly Christmas Island in the Indian Ocean.
Recent history of swimming with sharks
Until about 1961, young divers were scared stiff of all sharks and especially the words grey nurse shark. The older divers were obviously on an adrenalin high simply risking their lives, others considered, by swimming in the sea. Something only very brave men or fools did. Yet few sharks were being seen around Sydney. Even less was being speared. Where were they?
Early underwater documentaries
The first documentary cameramen easily obtained what was then in international terms very sensational film. The location was Brush Island NSW South Coast. The B&W 16mm footage showing a grey nurse being speared with a new type barbless spear. The cameraman swimming down and alongside these monsters to show the first ever seen close-ups of their numerous long and pointed teeth exposed.
Technical cinematography details
A 10mm wide angle lens on a hand wound Bolex camera allowed auto focus to within about 18 inches of the lens and about 20 seconds of film to be exposed at a time before winding was required. Perfect for breath hold diver photography. Scuba was still an unnecessary inconvenience for these experts in top physical condition.
Film production
A television station later edited and sound tracked the footage with a newsreel type narration into the famous award winning documentary titled The Shark Hunters. The first shark film underwater in Australia. It was a sensation. Australia was keen for information on these, the most feared of sea creatures.
First anti-shark weapon
Two years later an American diver with the uncanny name Scott G. Slaughter publicized his invention and experiences with sharks using a shotgun cartridge fitted to a handspear device he called The Powerhead
.
Ignorance of the sea
Meanwhile in Australia the word grey nurse was still associated with killer sharks. Almost all shark bites on every diver, swimmer or fisherman was credited to a grey nurse. It was not mistaken identity – few people including divers knew how to identify any shark. Sharks were sharks. Sharks were therefore grey nurse.
Australian device against shark attack
Pioneer underwater explorers (Dave Rowlings, Ted Louis, John Sumner, Ron Taylor) were experimenting in association with Shane Watson M.D. to perfect a poison when injected that was capable of killing a shark. Most effective was strychnine nitrate; it took about 30 seconds to paralyze a small shark when injected from a heavy duty hypodermic syringe fitted to a spear. The invention of explosive heads in USA and the subsequent copying by backyard mechanics made the injection technique obsolete.
Confidence booster
What had been shown while filming grey nurse was a considerable morale boost to skin divers all over the world. It showed for the first time that sharks in a school would not instantly tear a person to pieces as we had come to believe especially following the horror stories of World War II shipwreck survivors who saw terrible and real things that shark schools were capable of when hundreds of injured men were grouped together in the sea.
A fisherman’s book helps divers
The knowledge change began with a little book Sharks and Other Predatory Fish by Peter Goadby, a specialist with big game fishing. It showed with diagrams and text how to distinguish the species of whaler, tiger, pointer and grey nurse shark from each other.
Step one: The number of dorsal fins (grey nurse has two of equal size).
Step two: Note the upper and lower tail lobe lengths, (only white and blue pointer sharks have tail lobes of equal size). Tigers have vertical stripes more prominent in younger sharks than the older ones. All the whaler sharks, (now called bull sharks) were grouped into a single species as in those days few scientists studied shark. Hammerhead sharks had the obvious head that distinguished them from all others.
Labradores of the Sea?
To call any shark "harmless" would be a mistake. The grey nurse is capable of killing a person just as a stingray is, although remote this can happen. Rare circumstances occur, use the stingray's response to a close swimming snorkeler last year at Batt Reef, Queensland as one example.
An ancient Chinese saying: Repeat a lie one thousand times and it will become a truth.
Example
Environmentalists honestly believe just 500 grey nurse (Labrador's of the Sea)are left. Yes maybe this was so at the one dozen or so popular common dive sites - not everywhere.
The sea is vast.. The well-intending folk do not go everywhere. Their concerns are reported by short sentences in the media.
Deep water is unexplored. Spear fishermen visit countless reefs ignored by dive shops running tour dives. Paying divers want action not surveys
.
Shark attack myth
Another common myth concerning shark bites has almost become a truth.
Myth. "A shark mistakes a diver in a black wet suit for seal when it attacks".
This is ridiculous theory to those with practical knowledge.
It assumes sharks are stupid. All fast swimming sharks are predators. Some, like the tiger, eat anything. Why occasionally one will spit out a diver it has bitten and rip another to pieces that are never recovered is a puzzle. It is certainly not the shark thinking "oops, a human, I don't eat them".
Sharks would have better eyesight than we underwater plus many advanced sensors to help hunting and navigation. If we swim amongst seals that are possibly being stalked by a large shark then expect trouble. It’s no mistake, just something to be expected.
There’s another factor with sharks that use a nictitating membrane to protect their eyes. When a white pointer decides to bite while swimming at speed it may not be able to change this program at the last moment when close to the prey.
There are still a lot of interesting and fascinating unanswered questions.
Future scientists (AKA marine biologists)
May consider this research project. It's been noted that rocky reefs touching the east coast especially those between Bermagui and Eden on the NSW south coast have good and bad seasons underwater, as per the varying seasons on land linked to rainfall.
These poor undersea seasons have not been well documented yet would be common knowledge to professional abalone divers. The seasonal changes must have some affect on the marine food chain all the way through to possible variations with fish and shark populations.
(A simple observation noted and told to me by a farmer turned abalone diver from Tathra on the NSW south coast, Eddie Koellner).
