European Stars and Stripes (Newspaper) - January 12, 1993, Darmstadt, Hesse Hunted for their fins Sharks Are vanishing from oceans we of a. Pc a to Vav us. .v1. Put a if a a a a a a a it a i cd in sgt Abar Irit a ii a pm Rcw ill j4/ a. A a i myth hint.1 in my �5vi� we we. Ritj to a a a a a 0mm a k a a a a it. A Ffilfc-,4v fit i Vav. A Quot vv.v.�?Tv-,2 a. Via by a it a Vvs a it m a a a Ltd a a Ltd. .<_.k. A 4. A re Vav a a Aaby William k. Stevens the new York times t he shark that mythic terror of the deep has been top predator of the seas for nearly 400 million years. But Sharks themselves Are now being wiped out in Masse by the human appetite Tor shark flesh and their disappearance could disrupt the ecology of the worlds oceans. The threat comes just As scientists Are reaching beyond the jaws image of the shark As a primitive mindlessly malevolent eating machine that has Long shrouded the beast s True nature behind the legend researchers Are finding a wondrously sophisticated animal whose biology once understood could also yield important medical benefits. Lured by a shark Fin and shark meat Market that has soared in the. Last decade fishermen Are killing Sharks so fast that scientists fear entire populations Are threatened. If the Pace of the killing continues the decimation of the oceans top predator could throw Marine ecosystems. And food webs severely out of Kilter with possibly catastrophic consequences for other commercial. Fisheries. A a. A. The National Marine fisheries service has been struggling for More than three years to come up with a plan for stemming the Slaughter. The Agency is being criticized As too slow by scientists and conservationists who note that Sharks slow reproduction rate cannot keep up with the depletion of their numbers. With some conservation groups threatening to take Legal action or. Bill Fox director of the fisheries service. Has set an admittedly tentative deadline of this month for producing a regulation Planit. The great White shark a the ultimate Marine predator and knife toothed subject of movies and nightmares alike a a May be one of the most threatened As a species. Great Whites Quot Are in trouble everywhere they go Quot which is almost everywhere in the world said Samuel h. Gruber of the University of Miami a leading authority on Sharks. Quot they re out on an evolutionary limb and it s being sawed off i m shark experts recognize that the Public will never. Come to View Sharks with affection. The great White after. All is Quot not an affable Teddy Bear whose reputation is completely undeserved Quot Richard Ellis and John e. Mccosker wrote in a 1991 Book great White shark Harper Collin but biologists insist that popular myth is wrong in Many respects and that there is much to appreciate about the Are More than 350 species of shark ranging from the tiny pygmy shark to the giant whale shark. Some prey on Large Marine creatures others live by straining Plankton from the water. As a group they Are seen by scientists not As Dull primitive gobblers but As extraordinary biological machines. 1 their sensory system Quot has to be one of the most advanced among vertebrates if not the most advanced Quot says or. Timothy c. Tricas a shark biologist at the Florida Institute of technology in Melbourne. They Are Able to hear the sounds of fish swimming at a distance. A a a a a they can detect the Smeloff As Little As one drop of fish extract in a Quarter acre Lagoon 6vmeet deep. Their eyes which enable them to distinguish colors. Employ a Lens seven times As powerful As a human s and include a sort of. Mirror behind the Retina called the v a a tape Tum that reflects images and Power. Microscopic Nervo and hair cells on Sharks skin. Enable them to feel the presence of moving objects in their Vicinity. J. A a a a a sixth sense seated in Small canals on the. Sharks snout and lower jaw and poetically named the Ampulla of Lorenzini enables it to sense Bio electric Fields radiated by other sea creatures., through these electro receptors a shark can detect for instance the heartbeat of a Flatfish buried in the Sand. The receptors May also allow Sharks to navigate by .1 sensing variations in the Earth s magnetic Field. A the information from this array of sensors made to order for the role of top predator is Analysed integrated and acted upon by a relatively Large and Complex brain comparable in size and function to that of supposedly More advanced animals Tike Marn Mals and Birds. The immune system of Sharks and their close relatives skates and rays appears to make them All but Invulnerable to cancer and infectious diseases. Or Carl Luer a biochemist and shark biologist at the Mote Marino Laboratory in Sarasota fla., injected Many nurse Sharks with potent chemicals known to cause cancer in other Laboratory animals Over an eight year period. Quot we were not Able to produce even Early changes that would indicate a tumor was being formed Quot Luer said. If scientists can find out what is responsible for this resistance and for Sharks resistance to infection generally it could open the Way to vast medical benefits. To that end Luer and others Are investigating the immune cells of Sharks to determine whether they Are More efficient than those of humans and if so Why. Quot if we can describe the differences and similarities we might be Able to pinpoint what s responsible for Sharks Success Quot Luer said. Quot but we be got a Long Way to . Some Sharks including the great White the make and the Thresher Are War blooded. And contrary to the myth Sharks Are not eating machines constantly on the Lookout for a victim Gruber working with Lemon Sharks in the Bahamas has found that they feed Only about every second or third Day. Lemon Sharks can be studied in Captivity because unlike Many other Sharks they do not have to swim constantly to Force water Over their Gills Gruber found that a Sharks digestive tract works very slowly it May take four Days to digest a meal. This May be Why Sharks take 15 years or longer to grow to maturity and Why they grow even More slowly during the rest of a life Span that can reach 100 years in some species Quot i think this has an important evolutionary meaning Quot says Gruber. Quot it allows the shark a kind of luxury that we see in Many predators. It is not forced to eat All the time to keep up with demands for growth and activity. It can go on a feast or famine regime Quot As the availability of prey allows or requires. Shark reproduction can be a somewhat violent affair since the male typically holds the female with his Teeth. Females have consequently evolved thicker skin. In most species the fetus is nourished through a Placenta just like a human fetus and the Young Are born fully developed. But some species Lay eggs. In others some eggs Are fertilized inside the Mother. But others remain unfertilized and Whon the unborn baby Sharks develop Teeth they eat the unfertilized ones. In one species the Sand Tiger shark several fertilized continued on Page 20 the shark family thera i no Quot typical Quot shark. Tha species in this order include giants like the whale shark midgets like the cookie Cutter and an assortment of colourful oddballs like the Hammerhead. Approximately 70 percent of living Sharks belong to one family the and Thea example car Charnus Ambler honchos the Grey reef shark is one of them. Eyes that Shine like cats Sharks eyes shins because of the presence of a special membrane behind the Retina called a tape Al plans which reflects Light Back to the Lens. Again Ilka cats some Sharks also have a dictating eyelid to protect the Eye. The fascinating fearful a swimming computer with More sensory inputs than any other animal and a Large complicated brain for integrating the information the shark has been called a Quot swimming despite its Superb biological endowment however scientists fear that continuation of its nearly 400-Milllon-year existence May be in question. The decimation of shark species might disrupt the entire ecology of the world s oceans. The better to hear you with with two acoustic systems Sharks have a capacity Lor tensing underwater vibrations so acute it Haa been called a touch at a vibrations tens of feet away can guide them to prey or to other Sharks. The sensors Are in tiny openings on the top of the head with another set along the lateral line and la pm organs. Smell taste temperature Mouths nasal passages and skin surfaces especially the snout Art lined with exquisitely sensitive receptors not surprisingly these Hunters can sense the chemicals in blood and meat in tiny concentrations. Chemical cues May also help test the salinity of water end sense events like volcanic eruptions and chemical spills. Electro reception. Sharks can sense electrical Fields in the sea produced by the Earth s magnetic Field by oceanic currents like the Gulf Stream by animals and by shipwrecks. Along the lateral line and particularly on the snout and Cheeks Are patterns of pores leading to the electro receptors Jelly tilled canals called the Ampulla of Lorenzini. Sharks May employ this electrical sense to Orient themselves during Long distance migration is Well As using it to investigate prey and metallic 18 the stars and stripes tuesday january 12, 1993 the stars and stripes Page 19 or a
