|
Index:
<1) What's happening on the African Diving Experience
<2) Shark of the month - Bull Shark (a.k.a. Zambezi)
<3) Tiger Shark Feeding on Aliwal Shoal, good or bad?
<4) Book Review - Reef Fishes and corals: Eastern coast of southern Africa by Dennis king
<5) Tired of the same old dive sites? Dive the unexplored waters of Island Rock. Best of all its local!!!!
<6) Equipment tips -how to maintain your cylinder
<7) Website of the month
1. What's happening on the African Diving Experience
We would just like to remind you that the winter is coming and this is the time of the year when equipment
specials starts to pop up. So if you need some more gear, this is the time of the year you should be looking.
Do keep in mind that even if it is cold in the Gauteng and inland areas, diving is still absolutelly amazing at the Natal Coastline.
We added the following dive sites to our growing list of locations:
Protea Banks - With the help of Roland Mauz from African Dive Adventures
Wondergat - With the help of Micheal Holtzhausen from the Technical Diving Academy
inLichtenburg.
Special thanks to both these people for helping us in supplying all of our visitors with dive site information.
Talking about dive sites, have a look at article 3 of this newsletter about diving in Island Rock. That trully
sounds amazing.
We are still trying to gather information on diving locations in in the Cape province. If anyone can help us get
in touch with such information, please contact us as soon as possible.
Interrested in a banner exchange? Do contact us at the following e-mail willem@dpa-training.co.za
2. Shark of the month - Bull Shark (a.k.a. Zambezi)
Class: Chondrichthyes (Cartilaginous fish)
Sub class: Elasmobranchii (Sharks and rays)
Order: Carcharhiniformes (Ground sharks)
Family: Carcharhinidae (Requiem sharks)
Genus: Carcharhinus leucas (Bull shark)
Bull Shark ( Carcharhinus leucas)
Known in SA as the Zambezi Shark.
The bull shark is known as the Zambezi as it has been found several hundred kilometers up the great Zambezi River and seen in Zambia.
The Zambezi is a large shark (the total length up to 3,2 meters) with a short, broad and blunt snout, small
eyes and triangular, saw-edged upper teeth. This is a Grey shark with a white underside, with no conspicuous markings on the fins. The Southern limit off the East Coast of Africa is Cape St. Francis. The Zambezi is our summer shark and leaves after the sardine run June / July and avoids our August cold water and is seen again early October.
The Zambezi is able to maintain its electrolytic balance whether in the ocean or in fresh water for extended
periods. 40 years ago it was common to see the Zambezi make its way over the sandbank barring the
entrance of the Umkomaas River, so as to hunt grunter and bream up stream. The river is now so silted up
from soil erosion this incredible sight is no longer possible. However Mtunzini, St Lucia estuary and the Kosi
bay estuary are prime areas for the Zambezi to drop her pups, as they provide prime shelter for the Zambezi
pups, with plenty of suitable prey. The St Lucia Estuary when the river is in flood, the Zambezi can still be
seen worming their way over sandbanks to get into the estuary after grunter and bream. The Zambezi is even seen chasing shoaling fish onto the beach and themselves beached, at the estuary mouth, and waits for the next wave return them back to the sea. The female Zambezi is also seen in the St. Lucia estuary or at the estuary mouth, jumping out of the water and spinning in the air to facilitate dropping her pumps.
The Zambezi is well adapted to feeding without the use of its eyes; hence it has small eyes and not handicapped in finding prey in the zero visibility of the Zambezi River, or turbid coastal waters. The
explanation of a shark attack being caused by the similarity of image, was the US Navy’s explanation for a
shark attack, whereby a surfboard was considered similar to a turtle and someone in a wet suit imaging a seal or a dolphin. Current research indicates that a top hunter practices. Hence someone bitten in turbid water on a surfboard or swimming and let go is an unfortunate incident. This is not an attack but an incident, yet the media miss represents the happening, as the drama sells print. Humans are not part of the shark’s food chain and if in clear water and clearly seen by the shark, such a mishap as described is unlikely. For divers there has yet to be an unprovoked attack on a diver by a shark!
The main culprit of the shark attacks / incidents, off the KwaZulu Natal coast, was attributed to be that of the
great white. Re evaluation of the photographed bites indicate that the main culprit is the Zambezi. The
International Shark attack file is also being re-evaluated and many recorded white shark attacks / incidents,
have now been identified as that of the bull shark. The bite profile and upper triangular teeth of large bull
sharks are easily mistaken for the bite of a white.
The Zambezi is a powerful omnivorous predator and feeds on a wide variety of bony fish, sharks, rays,
mantis shrimp, craps, sea snails, squid, mammalian carrion, sea turtles and occasionally garbage.
Environmental accounting is a method of assessing the live value of a natural resource. The tourism money
that the Zambezi's draw to the towns adjacent to the Protea Banks is R50000 per Zambezi seen. A dead
Zambezi is only a fraction of this value and should be protected against indiscriminate killing by fishermen and spear-fishermen. We also have a major problem with unmonitored foreign trawlers in our EEZ long-lining and finning. The present Sea fisheries / Marine Coastal Management act states that these vessels should have satellite tracking and South African observers aboard. Marine Coastal Management banned finning 5 years ago, but so far none of this legislation has been applied or enforced. President Bill Clinton’s last act whilst in power was to ban finning in the American EEZ.
By: Andrew C. R. Cobb, (Andy) Tel/Fax 27 (0)31 9164239
P. O. Box 386, Winklespruit, 4145, South Africa
Email: andycobb@iafrica.com, http://www.adventurescuba.co.za
SATSA Member #: 766 |
|
