August 2002

DEBATE ABOUT WHALESHARKS
IN THE GULF OF AQABA

During the summer months, from June to August, many whalesharks visit the Gulf of Aqaba.

Actually seeing a whaleshark is a spectacular event: this is the largest fish on earth and in many instances can be larger than a whale. The dimensions of a really large whale shark are awe inspiring. The largest specimen ever measured accurately was caught by accident in 1983 off Bombay, in a gill net by a 20 foot boat. For a while the crew were terrified as they were towed around the ocean by the shark which was nearly twice the length of the boat. The 12.18 meter male specimen weighed in at 11 tonnes. The mouth was 1.36 meters wide. The dorsal fin was 1.37 meters (over four foot) high. The pectoral fins were over 2 meters long. An even larger specimen estimated at 18 meters in length was reported from the Gulf of Siam in 1925, but may have been overestimated.

Whereas whale sharks are found in tropical oceans throughout the world, scientists know little about these sharks because they are so rare. A few whale sharks have been kept alive and studied in enormous aquariums in Japan.

Whale sharks are dark gray to reddish-brown with large white spots on the upper side of the body. They are pale white or yellow underneath. They have broad, flat heads with a wide mouth. Adult whale sharks have more than 300 rows of tiny, hooked teeth and a row of replacement teeth behind these. They feed mainly on plankton. Whale sharks lay eggs the size of footballs. Newly hatched young are about 2 to 3 feet (60 to 90 centimeters) long.

There are certain features of the whale shark that distinguish it from other sharks. The most obvious is the very broad head. and its very wide mouth which is right at the front of the head, rather than being slung underneath the head as in other species. The eyes of the shark are small and located behind the angle of the jaw. The shark closes its eye by rotating it and sucking it back into its head.

It has nothing in common with whales except for its size and the fact that it only eats minute plankton by scooping it up whilst its mouth is wide open. It usually feeds on or just below the surface. It has on occasion, been observed eating fish larvae, krill, squid and sardines. Normally the whale shark opens its mouth about 200mm to breathe, but when feeding it is able to open it 2-3 times as wide. Usually, the sharks feed passively, cruising along beneath the surface with their mouth wide open.

It is believed that maturity is reached between twenty five and thirty years of age. This maturity age suggests that they may live well over one hundred years.

They are very docile and gentle and, when approached by snorkellers or divers are quite unworried by the visit. The whale shark is one of the surviving giants of the ocean that has remained a mystery to fisherman, divers, and scientists alike until very recently. It is not known how far whale sharks migrate. Recent studies have shown that whale sharks' migration can take them hundreds and even thousands of miles. One report showed that a single whale shark, equipped with a satellite tag, traveled 14,000 miles in 40 months (Brent S. Stewart, Ph.D. & Hubbs-Sea World Research Institute). At one time it was suggested that they might undertake huge migrations, breeding in the Indian Ocean, and drifting south in the Mozambique current around Cape Horn into the Atlantic, where they might be carried across the Atlantic in the Southern equatorial Current, reaching the Caribbean.

You can perhaps imagine that this sized fish is a challenge for the local boatmen, who consider a whaleshark much as the Bedouin consider the gazelle - but bigger, and hence more interesting! A number of people are becoming concerned about the apparent lack of concern on the part of the authorities for the endangered species which are the targets of these "hunters".

There is also some surprise that no authorization has been granted for organising "whale shark spotting cruises" from Aqaba as is done in many parts of the world. Several such are described in the websites listed below - the first of them has a fascinating description of diving with whalesharks :

www.millhouse.nl/ whalesharkencounters.html
http://www.ningalooreef.com/
http://www.worldwidediving.com/specialtours.htm
http://www.users.bigpond.com/coralbay/index.htm

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