<1) What's happening on the African Diving Experience
<2) Shark of the month - Basking Shark
<3) Fish Identification tips - Masked coachman, the normal Coachman and the Moorish idol
<4) Book Review - Small boat diving by Steven M. Barsky
<5) Forth Coming Events
<6) Equipment Specials
<7) Web site of the month
<8) How to stay clear of the panic zone.
1. What's happening on the African Diving Experience
As promised in the July issue of the Loggerhead, we have been adding some information to the contents of the site. The following items have already been added:
The Moray articles by The East Coast Fish-Watch Project, as seen in Divestyle.
Diving Locations: Diving in Umhlanga Rock's with a few more on the way.
We would just like to add a special thanks to the following companies for contributing dive site information to our list of diving locations: Keryn's Dive School in Port Alfred, Dive Nautique in Umhlanga Rocks, Orca Industries in Claremont, The Whaler in Umkomaas and Alpha Dive center in Gordon’s bay. Unfortunately we where not able to have all the new information uploaded to the site but we will have it up soon.
On 29 July 2001 we where invited to attend the launch of Dive Lockers new dive club. The event was in the form of a mid-winters dive at Bass Lake. With water temperature at 14oC it was a bit cold but non the less we had a fantastic day. Thanks to all who made the day possible.
Interested in a banner exchange? Do contact us at the following e-mail firstname.lastname@example.org
2. Shark of the month - Basking Shark / Koesterhaai
Class: Chondrichthyes (Cartilaginous fish)
Sub class: Elasmobranchii (Sharks and rays)
Order: Lamniformes (Mackerel sharks)
Family: Cetorhinidae (Basking sharks)
Genus: Cetorhinus maximus (Basking shark)
The Basking Shark has a very long, cylindrically shaped trunk and a very pointed snout, with a large, sub terminal mouth, with minute hooked teeth and big eyes. Extremely large gill slits that nearly extend ventrally and dorsally around the head helps distinguish this shark from many others. It's first dorsal fin is large, erect and triangular with it's origin, well behind the free ends of the pectoral fins. The second dorsal fin is much smaller than first one. It's body is covered with placoid scales and has a blackish colour. It has a maximum total length of about 1520cm with, an average size, between 900cm and 1000cm. It is rarely
caught under 300cm with the smallest specimen ever caught, sized at 170cm.
Basking sharks live over the continental shelves in pelagic but not oceanic waters. They are highly migratory, with seasonal appearances in certain localities and subsequent disappearances. They can be found alone or in aggregations of up to 100 animals. They are found on the bottom of deep water during winter. Basking sharks are probably the original subject of the 'sea monster' stories since they prefer to swim directly under the water surface, with their dorsal and caudal fin penetrating the surface, and sometimes follow each other.The Basking Shark feeds by filtering copepods, barnacles, decapod larvae, and fish eggs from the water. They are able to filter about 2000 tons of water per hour. Basking sharks are nearly positively buoyant
due to their large livers, up to 25% of their total weight, that are filled with certain oils.
Basking Sharks are aplacental viviparous (ovoviviparous), probably with an uterine cannibalism. Their size at birth and litter sizes are unknown since, pregnant females are hardly ever caught. Males seem to reach sexual maturity between 400 to 500cm The Basking Shark is considered to by very sensitive to over fishing, ascribed to its slow growth rate, lengthy maturation time, long gestation period, low fecundity and probable small size of existing populations. Basking sharks are legally protected in some territorial waters. They are utilised fresh, frozen and dried, or salted and is also valued for its liver (for oil), fins (for soup), hide (for leather) and carcass (for fishmeal).
It is regarded as ordinarily harmless and inoffensive but potentially dangerous if attacked (particularly when harpooned).