Newsletter - 02/02/2001

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The Loggerhead

The Official newsletter for The African Diving Experience
www.africandiving.com
Volume 3 Date: 02/02/2001


First of we are looking for websites with dive site info on them. Anyone aware of any sites containing information on diving and reef info, please contact me at willem@dpa-training.com

We hope you enjoy the 3rd issue of our monthly newsletter.

Index:

<1) What's new on the African Diving Experience
<2) Shark of the month - Leopard Catshark
<3) Coelacanth Project
<4) Book Review - The Divers Handbook
<5) Diving responsibly with sharks
<6) Equipment discussion - Customize your equipment
<7) Websites of the month
<8) Helpful diving hints - Managing Seasickness

1. What's new on The African Diving Experience

Andy Cobb has supplied us with some interesting information on shark human interaction as well as the correct protocol when diving with sharks. Be sure to have a look at the "diving responsibly with sharks" article for more info.

Ever seen the fishwatch articles in Divestyle magazine? Well you will be able to view the complete unedited version of the Triggerfish article, including photo's not published in Divestyle, on the African Diving Experience. As soon as the section is approved by, Phil Heemstra of the JLB Smiths institute, we will activate the link to this section.

We are looking for help updating our equipment section. If anyone would like to make a contribution please contact me.

We will be adding a new part to our website dedicated to the medical problems a diver must face. Some causes are given and in some cases how to relieve the symptoms. These pages will give a brief summary of the problems but a diving physician or doctor should always give a final opinion.

If there is any specific issue or any idea you would like to see on the African Diving Experience please contact me at: willem@dpa-training.com

2. Shark of the month - Leopard catshark
Class: Chondrichthyes (Cartilaginous fish)
Sub class: Elasmobranchii (Sharks and rays)
Order: Squantiniformes
Family: Scyliorhindae (Catsharks)
Genus: Poroderma Pantherinum (Leopard Catshark)

This is a smallish member of the catshark family having a max size of 65 cm and an average size of 50 cm. It is recognized by long nasal barbells and large black spots on the side and back. It is a relatively abundant shark and occurs from the northern part of the Eastern Cape to about St. Lucia and maybe even Sodwana. It lives in relatively shallow water on rocky and sandy bottoms. The female attaches the eggcases to underwater vegetation and the young are produced from these. Dorsal spines (total): 0-0; Anal spines: 0-0.  There are 3 different forms, the typical 'pantherinum' with lines and rosettes of spots, and two extreme forms, 'marleyi' with large dark spots (formally considered a separate species), and 'salt and pepper' with small, densely packed black spots, intermediates between these extremes are extremely common. The leopard catshark feeds on small bony fish, crustaceans, octopus and polychaete worms.

Catshark
Catshark

The two versions of the Leopard catsharks patterns

Source: Smiths' Sea Fishes (1986) p103, Sharks and rays of Southern Africa p8

3. Coelacanth Project

The JLB Smith Institute of Ichthyology are looking for corporate sponsors to help finance the following project. If you are aware of anyone who would like to make a contribution or to find out more about the project, please contact Phil Heemstra at the following e-mail address: P.Heemstra@ru.ac.za

MOTIVATION FOR A JOINT RESEARCH PROJECT OF THE JLB SMITH INSTITUTE OF ICHTHYOLOGY AND MAX PLANCK INSTITUT FÜR VERHALTENSPHYSIOLOGIE ON THE BIOLOGY, ECOLOGY, AND CONSERVATION OF THE COELACANTH (LATIMERIA CHALUMNAE) POPULATION OFF THE COAST OF KWAZULU-NATAL

The recent discovery of six coelacanths in the Jesser Canyon at Sodwana Bay in northern KwaZulu-Natal presents a wonderful opportunity to learn more about this fascinating fish. This discovery also has great potential to stimulate ecotourism and the appreciation of the rich fish diversity of South Africa.  As we learn more about this “living fossil”, we will be better equipped to understand its role in the deep-reef ecosystem and also develop policies that ensure its continued survival.

The discovery of a several Latimeria chalumnae at one of the most popular diving resorts on the coast of KwaZulu-Natal some 62 years after the first living coelacanth was found near East London, and the continuous addition of new records that are produced with the East Coast Fish-Watch Project and our fish survey work of the past 22 years indicates that we still have much to learn about our rich fish diversity.

QUESTIONS TO BE ANSWERED AND INFORMATION TO BE PROVIDED BY THIS RESEARCH PROJECT ARE AS FOLLOWS:

1.What is the size of this population?  Estimation of the population will be facilitated by the unique colour patterns of Latimeria.  The visual catalogue of individual fish compiled by Prof. Fricke and his team has proved of great value in monitoring the local population in the Comoros.

2.Scale sampling of as many individual fish as possible for genetic comparison with the other Latimeria populations in the Western Indian Ocean and to determine the genetic variability within the South African population.  This non-injurious sampling is easily done with the submersible. 

3.Acoustic tagging to assist with tracking movements of individual fish and also to map the occurrence of suitable caves which are important to the lifestyle of Latimeria.  Knowledge of the movements, habits and “lebensraum” of coelacanths is necessary to understanding its role in the deep-reef community.  And this information will also be valuable in determining the optimum  placement of an underwater video camera that can be used to study this fascinating fish and also to share the beauty of its graceful movements and peaceful behaviour with tourists on shore.  A real-time televised picture of live coelacanths in the wild will be of great benefit to ecotourism and the KwaZulu-Natal Nature Conservation Service.

4.Extending our studies of the other obligate and facultative members (fish species) of the deep-reef habitat of Latimeria.  Most of the other fishes that co-occur with Latimeria are potential prey, and a few may be competitors or predators of Latimeria.

PRODUCTS OF THIS RESEARCH PROJECT:

1.A video on the South African coelacanths, local fish diversity, St Lucia Marine Reserve, and the J.L.B. Smith / Max Planck research work.

2.Increased appreciation of South African fish diversity and the need to protect it.

3.Popular books and scientific papers on the South African coelacanth and other members of the deep-reef community.

 

4. Book Review - The Divers Handbook

Written by Alan Mountain the Divers Handbook covers all the aspects of diving staring with the history of diving and ending in an overview of diving specialities. The book tells you how to choose your equipment and what basic training courses to attend. Subjects like health, safety and the marine environment are also covered with a section on some of the different diving specialities like, underwater photography, ice and wreck diving. Those of us who like pictures will enjoy the more than 300 high quality photographs and illustrations.

5. Diving responsibly with sharks

Diving with sharks is a magical experience that leaves a new found respect for these amazing creatures. Being up close to the predator of the oceans is an experience I will never forget. However if we are not careful in the manner we approach these amazing creatures they will not be sticking around on our reefs for much longer. By following a few simple rules we can increase the amount of enjoyment in such a shark encounters and preserve it for future generations to enjoy as well.

Remember we are not part of the shark's food chain. When a shark bites and lets go it is a case of mistaken identity.

Here is a couple of things to keep in mind when diving with sharks:

  • Keep out of the caves, gullies, caverns, sandy patches and overhangs, where the sharks are resting.
  • Don't block the shark's exits or wedge the shark towards the reef.
  • Respect the shark's space and approach cone limitations to be accepted for a memorable encounter.
  • The sharks are often inquisitive. Should a shark approach, breathe slow and easy, keep still, do not use hands to maintain buoyancy and Enjoy the privilege.
  • A fast moving shark can be an agitated shark. Stay together and move with slow and steady rhythm, keep relaxed and move away if necessary.
  • Respect and enjoy the shark, view so that they are undisturbed for the next group to enjoy.
  • Sharks are masters of their marine environment, we are not in their food chain. Respect means understanding the marine rhythm and blend in with the shark's environment.

 Find out more about shark diving protocol by visiting http://www.delportdupreez.co.za/diving/html/shark_protocol.html
or by contacting Andy Cobb at the following e-mail:
andycobb@iafrica.com
 Information on shark diving protocol was supplied by Andy Cobb.

6. Equipment discussion - Customize your equipment

This month we will give you some tips on how to modify your kit to make it more functional and personal. All the tips are from www.scubadiving.com where more can be found.

Regulators
Trim the mouthpiece. If some part of the flange that fit between your teeth and your lips bother you, trim if off. Your local dive shop will even be able to give you the name of a dealer who makes personalized mouthpieces for you.

Instruments
Attach your console to a retractor cord. This keeps your console close to you and off the reef. Just check and let go!

BC’s
Organize all your gadgets. As all these toys have to attach to the BC it is more comfortable to arrange it in a position which suits you and minimizes drag. Some toys are better off lower on the BC than others.

Masks
Seal leaks in your mask skirt by smearing it with a little silicone grease. This will help especially with leaks caused by facial hair. NEVER use petroleum products or solvents as these will eat away at silicone and damage your mask.

Exposure suits

  • Making a small hole in the bottom of your bootie with a hot nail will help it drain quicker after the dive, especially while still on the boat.
  • Trim your hoodie face. They come intentionally smaller so you can trim them to fit you. This will also cause less claustrophobia.

7. Websites of the month
The following site was our choice for websites of the month:

www.gulftel.com/~scubadoc
This is website with detailed information on all of the medical problems a diver might encounter. Some treatments are also given as well as symptoms.

Woodville Karst Plain Project (www.wkpp.org)
This is a site for cave divers. There is however interesting articles on customizing your scuba gear that can also be used by casual divers. Well worth a visit.

8. Helpful diving hints - Managing seasickness

Cause: Seasickness is caused by a disruption of orientating sensory information to the brain.

 Predisposing factors: Alcohol, Overeating, Age (younger people), Females (probably due to less boat exposure), Sensory confusion of inner ear sensors, Psychological factors

 Prevention:

  • Eat lightly and do not drink alcohol the night before diving.
  • Ensure that all your equipment is placed in a logical and orderly fashion next to you on the dive boat.
  • Concentrate on factors that will assist the brain in orientating acceptably. The eyes and body should actively fix on steady bearings :
  • Keep the head upright and steady
  • Stare at the horizon
  • do not look down at the deck or water
  • do not try to read. This removes eye reference and makes things worse.
  • Anti seasickness drugs act by preventing seasickness rather then treating it, so it is logic that they are taken before seasickness starts.

 Adapted from How to manage diving problems by Allan Kayle

Preserve our oceans for future generations to share in it's splendour.
Willem du Preez and Tjaart de Beer
Web masters for the African Diving Experience

This newsletter was sponsored by:
+ Dpa Training - Computer training at your fingertips.
Special Thanks to the following people and company's for helping us obtain information for our website.
 +
Mseni Lodge and Amoray diving - Sodwana Bay
 +
Reefteach - Sodwana Bay
 +
Andy Cobb Eco Diving
 +
The East Coast Fishwatch Project

If you would like us to remove your name from the mailing list for this newsletter, please send an e-mail to willem@dpa-training.com with the subject unsubscribe.

Updated on: 06/03/2003