Newsletter - 06/07/2001

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The Loggerhead

The Official newsletter for The African Diving Experience
www.africandiving.com
Volume 8 Date: 06/07/2001

We hope you enjoy the July issue of our monthly newsletter.

Index:

<1) What's new on the African Diving Experience
<2) Shark of the month  - Spotted Spiny Dog fish
<3) Shark Feeding on Aliwal Shoal - Recent Developments
<4) Book Review - Marine Shells of South Africa / See Skulpe van Suid-Afrika
<5) Forth Coming Events
<6) Equipment Specials
<7) Website of the month
<8) Does no phone mean no e-mail? Here is a solution.
<9) How to manage Nitrogen narcosis

1. What's new on the African Diving Experience

We would like to thank all of you for your continued support in helping us obtaining information, to help promote diving in Southern Africa. We would also like to thank all who have supported the shark feeding poll by sending us their comments.

June has been a bit of a slow month but we promise that we will make it up to you in July. We are in the process of obtaining interesting information that we will add onto the site as soon as possible. Some things to look out for during July are: The Eel articles as published in Divestyle magazine and some interesting diving locations. Some interesting new features might also pop up. But we will keep you in suspense a bit longer.

If you would like to help us in obtaining any information for the website or even for this newsletter please contact us. Interested in a banner exchange? Do contact us at the following e-mail
willem@dpa-training.co.za

2. Shark of the month - Spotted Spiny Dog fish
Class: Chondrichthyes (Cartilaginous fish)
Sub class: Elasmobranchii (Sharks and rays)
Order: Squaliformes (Dogfish sharks)
Family: Squalidae (Dogfishes)
Genus: Squalus acanthias (Spotted Spiny Dogfish)

This is a common shark in the Cape and thus will be well known to cape divers.  It is a small shark with two dorsal fins with ungrooved large spines and no anal fin. The first dorsal spine origin is behind the pectoral rear tips. It has a grey brown upper body with whitish ventral surface and white spots along the entire body.

This is a well studied specie and is probably the most abundant shark specie of all. It lives preferably close to bottom and is slow swimming. It is found over the continental and insular shelves and upper slopes down to approximately 900m. The Spiny Dogfish can tolerate brackish water and is often found in enclosed bays and estuaries. It is relatively small with an average size of between 80 cm and 110 cm and a maximum length of about 160 cm.

It feeds mainly on fishes, preferably schooling fishes, invertebrates, cephalopods, crustaceans, and even sea cucumbers and jellyfishes.

It may have up to 20 pups per litter with a birth size of about 20 cm. Gestation period lasts about 22 months. Sexual maturity is reached at an age of about 20 years (sometimes even later) or a size of about 60 cm. It's maximum age is estimated to be around 70 years and is threatened in some parts of the world, since it is mainly used for "Fish & Chips."

It is harmless to humans.

Picture

Source http://www.shark.ch and http://www.fishbase.org

3. Shark Feeding on Aliwal Shoal - Recent Developments

Since our previous newsletter, Marine Coastal Management has had an open meeting on the the shark feeding at Aliwal Shoal. The meeting was held on 18 June 2001 and attended by the Natal Shark Board, Kwazulu Wildlife representatives, dive operators, Wildlife Society of SA and other interested parties.

The meeting came to a decision that Tiger shark feeding will be allowed at a location 1 km south of current diving locations and will be regulated via operator permits. The feeding of Ragged tooth sharks will however not be allowed. An appropriate code of conduct will also be set to regulate the feeding activities. Aliwal Shoal will be made into a Marine Protected Area. The northern boundary is the SAICCOR pipe-line and the southern boundary south off Rocky Bay and 7 kms out to sea.

Another open workshop will be held on wednesday, 22 August 2001. For more information on either of these two workshops you can contact Andy Cobb at the following e-mail address
andycobb@iafrica.com or you can contact us at willem@dpa-training.co.za and we will get you the information.

If you would like to air your opinion on this matter go to
http://www.delportdupreez.co.za/diving/form.htm or follow the link from our home page.

So far the results are as follows:
Number of votes received = 47
Stop the feeding = 40 (85,1%)
Keep on feeding them = 6 (12,8%)
The other person was not willing to choose a side.

We will send all results and comments on to the relevant parties before the next workshop is held.
Special thanks to 50/50 and Divestyle magazine for mentioning the poll.

4. Book Review - Marine Shells of South Africa/ See Skulpe van Suid-Afrika
                           By Douw Steyn and Markus Lussi

This is book for all those people who love to collect shells and some divers might find it interesting as well. It features full colour photographs of all the shells, which occur along the coast of South Africa. Along with a description of the shell they also give a distribution map and sizes of the shell. Another interesting feature, more to collectors than to divers, is an indication of the rarity of the shell (this is measured in how often a complete shell washes up on the beach). It is a very handy guide for those divers who like to look at shells when diving and don't know their name.

Ekogilde cc publishes this book.

5. Forth Coming Events

Shark Feeding Workshop - 22 August 2001 (See article 3 of this newsletter)

Watersport Africa Show - 31st August 2001 - 2nd September 2001, SuperSport Park, Centurion, South Africa, for further information, please contact Ross Harris - 082 824 7204 or e-mail to
watersport@rai.co.za or visit http://www.rai.co.za/watersport

6. Equipment Specials

We promised that we will inform you of all equipment specials as we become aware of them. Well here is a huge one:

There is a 25% sale on all SCUBAPRO and UWATEC products. To good to be true? The offer is in connection with  Divestyle magazine. Around the July/August edition of Divestyle there is a black band which acts as a voucher for the purchase. The voucher is valid until 24 August 2001 and certain conditions apply. Definitely worth looking into.

Be on the look out for other specials as this is the time of the year that specials seems to pop up the most.

For more information's about specials or any equipment related queries contact Richard at
info@oceandivers.co.za

7. Website of the month
The following site is our choice for website of the month:

http://www.nationalgeographic.com

As the official website for the National Geographic magazine, this site is very informative and a must to visit.

8. E-mail without a phone?

This sounds like it should belong in some kind of technical newsletter and definitely not in a diving newsletter. Well that might be true but lets think for a moment. Have you ever been to Mozambique for a diving vacation and was left without e-mail because there was no phone service available or had to cancel that vacation because you could not be in touch with the office. Well now you can break away from the office and still be in touch to ensure that the company doesn't go under without you. Here is how....

Bushmail is e-mail to and from the African bush via HF radio and the Internet. It provides a downtown office facility in the bush that facilitates data communications to and from anywhere in the world and all in under 10 minutes forwarding time. Stations installed in Botswana, Wilderness Safaris 14 camps, Moremi safaris, Landela safaris and 42 other African countries. You can sit under a tree in the African bush or under a Palm tree on an Island in the Mozambique Channel and send and receive e-mail to and from anywhere in the world. Its much cheaper than satellite communications, and in any case, short wave radio is still the most used means of communication in the remote areas of Africa.

Bushmail is used primarily by tourist operators, hunters, farmers, mining operators, missionaries, security organizations and even for e-mail communications between the world and 4X4 vehicles and houseboats. Also included among Bushmail users are explorers, adventurers, filmmakers and conservationists.

For more information contact: Atlantic / Bushmail Head Office Tel: (012) 342-0622 Fax: (012) 430-7922 or
mailto:skywave@lantic.net

9. How to manage Nitrogen narcosis

Nitrogen narcosis occurs when the partial pressure of the inhaled air is above 2.8 ATA. This usually occurs at 30m and deeper but has been recorded at 10m. It can also occur on a fast decent.

Some of the symptoms to watch out for are a general feeling of well being, changes in senses e.g. tunnel vision, changes in higher mental functions like the math ability of the person. Some other symptoms may also be a change in motor ability with uncoordinated and awkward movements.

Nitrogen narcosis disappears when the person starts to ascend and it leaves no permanent damage.

Updated on: 06/03/2003